commit 37b6adb6dee2dffa1e4b125ac8b55cd3ca0cb6c1
Author: DullJZ <79080562+DullJZ@users.noreply.github.com>
Date:   Fri Aug 22 21:15:56 2025 +0800

    first

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a35a948
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,48 @@
+# Binaries
+*.exe
+*.dll
+*.so
+*.dylib
+
+# Test binary
+*.test
+
+# Output of the go coverage tool
+*.out
+
+# Dependency directories
+vendor/
+
+# Configuration files (keep examples)
+config/*.yaml
+!config/*.example.yaml
+
+# Database files
+data/
+*.db
+*.db-shm
+*.db-wal
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# OS generated files
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+
+# Logs
+*.log
+logs/
+
+# Environment variables
+.env
+.env.local
diff --git a/cmd/s3-balance/main.go b/cmd/s3-balance/main.go
new file mode 100644
index 0000000..e888730
--- /dev/null
+++ b/cmd/s3-balance/main.go
@@ -0,0 +1,182 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/DullJZ/s3-balance/internal/api"
+	"github.com/DullJZ/s3-balance/internal/balancer"
+	"github.com/DullJZ/s3-balance/internal/bucket"
+	"github.com/DullJZ/s3-balance/internal/config"
+	"github.com/DullJZ/s3-balance/internal/database"
+	"github.com/DullJZ/s3-balance/internal/storage"
+	"github.com/DullJZ/s3-balance/pkg/presigner"
+	"github.com/gorilla/mux"
+)
+
+func main() {
+	// 解析命令行参数
+	var configFile string
+	flag.StringVar(&configFile, "config", "config/config.yaml", "Path to configuration file")
+	flag.Parse()
+
+	// 加载配置
+	cfg, err := config.Load(configFile)
+	if err != nil {
+		log.Fatalf("Failed to load configuration: %v", err)
+	}
+
+	// 初始化数据库
+	if err := database.Initialize(&cfg.Database); err != nil {
+		log.Fatalf("Failed to initialize database: %v", err)
+	}
+	defer database.Close()
+
+	// 创建存储桶管理器
+	bucketManager, err := bucket.NewManager(cfg)
+	if err != nil {
+		log.Fatalf("Failed to create bucket manager: %v", err)
+	}
+
+	// 启动存储桶管理器（健康检查和统计更新）
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	bucketManager.Start(ctx)
+
+	// 创建负载均衡器
+	lb, err := balancer.NewBalancer(bucketManager, &cfg.Balancer)
+	if err != nil {
+		log.Fatalf("Failed to create balancer: %v", err)
+	}
+
+	// 创建预签名URL生成器
+	signer := presigner.NewPresigner(
+		15*time.Minute,  // 上传URL有效期
+		60*time.Minute,  // 下载URL有效期
+	)
+
+	// 创建存储服务
+	storageService := storage.NewService(database.GetDB())
+
+	// 创建S3兼容API处理器
+	s3Handler := api.NewS3Handler(
+		bucketManager,
+		lb,
+		signer,
+		storageService,
+		cfg.S3API.AccessKey,
+		cfg.S3API.SecretKey,
+	)
+
+	// 设置路由
+	router := mux.NewRouter()
+	
+	// 运行在S3兼容模式
+	log.Println("Running in S3-compatible mode")
+	s3Handler.RegisterS3Routes(router)
+
+	// 添加CORS中间件
+	router.Use(corsMiddleware)
+
+	// 添加日志中间件
+	router.Use(loggingMiddleware)
+
+	// 创建HTTP服务器
+	srv := &http.Server{
+		Addr:         fmt.Sprintf("%s:%d", cfg.Server.Host, cfg.Server.Port),
+		Handler:      router,
+		ReadTimeout:  cfg.Server.ReadTimeout,
+		WriteTimeout: cfg.Server.WriteTimeout,
+		IdleTimeout:  cfg.Server.IdleTimeout,
+	}
+
+	// 启动服务器
+	go func() {
+		log.Printf("Starting S3 Balance Service on %s", srv.Addr)
+		log.Printf("Load balancing strategy: %s", cfg.Balancer.Strategy)
+		log.Printf("Managed buckets: %d", len(cfg.Buckets))
+		
+		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			log.Fatalf("Failed to start server: %v", err)
+		}
+	}()
+
+	// 等待中断信号
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM)
+	<-sigChan
+
+	// 优雅关闭
+	log.Println("Shutting down server...")
+	
+	shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer shutdownCancel()
+
+	if err := srv.Shutdown(shutdownCtx); err != nil {
+		log.Printf("Server shutdown error: %v", err)
+	}
+
+	// 停止存储桶管理器
+	bucketManager.Stop()
+	cancel()
+
+	log.Println("Server stopped")
+}
+
+// CORS中间件
+func corsMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "*")
+		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
+		w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization")
+		
+		if r.Method == "OPTIONS" {
+			w.WriteHeader(http.StatusOK)
+			return
+		}
+		
+		next.ServeHTTP(w, r)
+	})
+}
+
+// 日志中间件
+func loggingMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		start := time.Now()
+		
+		// 包装ResponseWriter以捕获状态码
+		wrapped := &responseWriter{
+			ResponseWriter: w,
+			statusCode:     http.StatusOK,
+		}
+		
+		next.ServeHTTP(wrapped, r)
+		
+		log.Printf(
+			"[%s] %s %s %d %v",
+			r.RemoteAddr,
+			r.Method,
+			r.RequestURI,
+			wrapped.statusCode,
+			time.Since(start),
+		)
+	})
+}
+
+// responseWriter 包装器用于捕获状态码
+type responseWriter struct {
+	http.ResponseWriter
+	statusCode int
+}
+
+func (rw *responseWriter) WriteHeader(code int) {
+	rw.statusCode = code
+	rw.ResponseWriter.WriteHeader(code)
+}
diff --git a/config/config.example.yaml b/config/config.example.yaml
new file mode 100644
index 0000000..b1c5484
--- /dev/null
+++ b/config/config.example.yaml
@@ -0,0 +1,129 @@
+# S3 Balance Service Configuration Example
+
+# 服务器配置
+server:
+  host: "0.0.0.0"
+  port: 8080
+  read_timeout: 30s
+  write_timeout: 30s
+  idle_timeout: 60s
+
+# 数据库配置
+database:
+  # 数据库类型: sqlite, mysql, postgres
+  type: "sqlite"
+  
+  # 数据源名称 (DSN)
+  # SQLite 示例:
+  dsn: "data/s3-balance.db"
+  
+  # MySQL 示例:
+  # dsn: "user:password@tcp(localhost:3306)/s3balance?charset=utf8mb4&parseTime=True&loc=Local"
+  
+  # PostgreSQL 示例:
+  # dsn: "host=localhost user=postgres password=password dbname=s3balance port=5432 sslmode=disable TimeZone=Asia/Shanghai"
+  
+  # 连接池配置
+  max_open_conns: 25      # 最大打开连接数
+  max_idle_conns: 5       # 最大空闲连接数
+  conn_max_lifetime: 300  # 连接最大生命周期（秒）
+  
+  # 日志级别: silent, error, warn, info
+  log_level: "warn"
+  
+  # 是否自动迁移数据库表
+  auto_migrate: true
+
+# S3存储桶配置
+buckets:
+  # 第一个存储桶 - AWS S3
+  - name: "my-bucket-1"
+    endpoint: ""  # 留空使用默认AWS端点
+    region: "us-east-1"
+    access_key_id: "YOUR_AWS_ACCESS_KEY_ID"
+    secret_access_key: "YOUR_AWS_SECRET_ACCESS_KEY"
+    max_size: "10GB"  # 最大容量限制
+    weight: 10  # 权重（用于加权负载均衡）
+    enabled: true
+    use_ssl: true
+    path_style: false  # AWS S3使用虚拟主机风格
+
+  # 第二个存储桶 - MinIO
+  - name: "my-bucket-2"
+    endpoint: "http://localhost:9000"
+    region: "us-east-1"
+    access_key_id: "minioadmin"
+    secret_access_key: "minioadmin"
+    max_size: "5GB"
+    weight: 5
+    enabled: true
+    use_ssl: false
+    path_style: true  # MinIO通常使用路径风格
+
+  # 第三个存储桶 - 阿里云OSS（兼容S3）
+  - name: "my-bucket-3"
+    endpoint: "https://oss-cn-hangzhou.aliyuncs.com"
+    region: "cn-hangzhou"
+    access_key_id: "YOUR_ALIYUN_ACCESS_KEY_ID"
+    secret_access_key: "YOUR_ALIYUN_SECRET_ACCESS_KEY"
+    max_size: "20GB"
+    weight: 15
+    enabled: true
+    use_ssl: true
+    path_style: false
+
+  # 备用存储桶（可以禁用）
+  - name: "backup-bucket"
+    endpoint: "http://backup-s3.example.com"
+    region: "us-west-2"
+    access_key_id: "BACKUP_ACCESS_KEY"
+    secret_access_key: "BACKUP_SECRET_KEY"
+    max_size: "100GB"
+    weight: 1
+    enabled: false  # 当前禁用
+    use_ssl: false
+    path_style: true
+
+# 负载均衡配置
+balancer:
+  # 负载均衡策略，可选值：
+  # - "round-robin": 轮询
+  # - "least-space": 选择剩余空间最多的存储桶
+  # - "weighted": 基于权重的随机选择
+  # - "consistent-hash": 一致性哈希（相同的key总是选择相同的存储桶）
+  strategy: "least-space"
+  
+  # 健康检查周期
+  health_check_period: 30s
+  
+  # 统计信息更新周期
+  update_stats_period: 60s
+  
+  # 重试配置
+  retry_attempts: 3
+  retry_delay: 1s
+
+# 监控指标配置
+metrics:
+  enabled: true
+  path: "/metrics"
+  port: 9090
+
+# S3兼容API配置
+s3api:
+  # 客户端连接用的Access Key
+  access_key: "AKIAIOSFODNN7EXAMPLE"
+  
+  # 客户端连接用的Secret Key
+  secret_key: "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"
+  
+  # 是否使用虚拟主机模式
+  virtual_host: false
+  
+  # 工作模式：
+  # false (默认)：预签名重定向模式，客户端直接与后端存储交互
+  # true：代理模式，数据通过S3 Balance服务器传输
+  proxy_mode: false
+  
+  # 是否需要认证（开发环境可设为false）
+  auth_required: false
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..234d852
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,45 @@
+module github.com/DullJZ/s3-balance
+
+go 1.24.5
+
+require (
+	github.com/aws/aws-sdk-go-v2 v1.38.0
+	github.com/aws/aws-sdk-go-v2/config v1.31.1
+	github.com/aws/aws-sdk-go-v2/credentials v1.18.5
+	github.com/aws/aws-sdk-go-v2/service/s3 v1.87.0
+	github.com/gorilla/mux v1.8.1
+	gopkg.in/yaml.v3 v3.0.1
+)
+
+require (
+	filippo.io/edwards25519 v1.1.0 // indirect
+	github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.7.0 // indirect
+	github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.18.3 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/configsources v1.4.3 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.7.3 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/ini v1.8.3 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/v4a v1.4.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.13.0 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/checksum v1.8.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.13.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/s3shared v1.19.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sso v1.28.1 // indirect
+	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.33.1 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sts v1.37.1 // indirect
+	github.com/aws/smithy-go v1.22.5 // indirect
+	github.com/go-sql-driver/mysql v1.8.1 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/pgx/v5 v5.6.0 // indirect
+	github.com/jackc/puddle/v2 v2.2.2 // indirect
+	github.com/jinzhu/inflection v1.0.0 // indirect
+	github.com/jinzhu/now v1.1.5 // indirect
+	github.com/mattn/go-sqlite3 v1.14.22 // indirect
+	golang.org/x/crypto v0.31.0 // indirect
+	golang.org/x/sync v0.10.0 // indirect
+	golang.org/x/text v0.21.0 // indirect
+	gorm.io/driver/mysql v1.6.0 // indirect
+	gorm.io/driver/postgres v1.6.0 // indirect
+	gorm.io/driver/sqlite v1.6.0 // indirect
+	gorm.io/gorm v1.30.1 // indirect
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..9d986a4
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,80 @@
+filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
+filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
+github.com/aws/aws-sdk-go-v2 v1.38.0 h1:UCRQ5mlqcFk9HJDIqENSLR3wiG1VTWlyUfLDEvY7RxU=
+github.com/aws/aws-sdk-go-v2 v1.38.0/go.mod h1:9Q0OoGQoboYIAJyslFyF1f5K1Ryddop8gqMhWx/n4Wg=
+github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.7.0 h1:6GMWV6CNpA/6fbFHnoAjrv4+LGfyTqZz2LtCHnspgDg=
+github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.7.0/go.mod h1:/mXlTIVG9jbxkqDnr5UQNQxW1HRYxeGklkM9vAFeabg=
+github.com/aws/aws-sdk-go-v2/config v1.31.1 h1:PSQn4ObaQLaHl6qjs+XYH2pkxyHzZlk1GgQDrKlRJ7I=
+github.com/aws/aws-sdk-go-v2/config v1.31.1/go.mod h1:3UA8Gj+2nzpV8WBUF0b19onBfz0YMXDQyGEW0Ru1ntI=
+github.com/aws/aws-sdk-go-v2/credentials v1.18.5 h1:DATc1xnpHUV8VgvtnVQul+zuCwK6vz7gtkbKEUZcuNI=
+github.com/aws/aws-sdk-go-v2/credentials v1.18.5/go.mod h1:y7aigZzjm1jUZuCgOrlBng+VJrKkknY2Cl0JWxG7vHU=
+github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.18.3 h1:GicIdnekoJsjq9wqnvyi2elW6CGMSYKhdozE7/Svh78=
+github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.18.3/go.mod h1:R7BIi6WNC5mc1kfRM7XM/VHC3uRWkjc396sfabq4iOo=
+github.com/aws/aws-sdk-go-v2/internal/configsources v1.4.3 h1:o9RnO+YZ4X+kt5Z7Nvcishlz0nksIt2PIzDglLMP0vA=
+github.com/aws/aws-sdk-go-v2/internal/configsources v1.4.3/go.mod h1:+6aLJzOG1fvMOyzIySYjOFjcguGvVRL68R+uoRencN4=
+github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.7.3 h1:joyyUFhiTQQmVK6ImzNU9TQSNRNeD9kOklqTzyk5v6s=
+github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.7.3/go.mod h1:+vNIyZQP3b3B1tSLI0lxvrU9cfM7gpdRXMFfm67ZcPc=
+github.com/aws/aws-sdk-go-v2/internal/ini v1.8.3 h1:bIqFDwgGXXN1Kpp99pDOdKMTTb5d2KyU5X/BZxjOkRo=
+github.com/aws/aws-sdk-go-v2/internal/ini v1.8.3/go.mod h1:H5O/EsxDWyU+LP/V8i5sm8cxoZgc2fdNR9bxlOFrQTo=
+github.com/aws/aws-sdk-go-v2/internal/v4a v1.4.3 h1:ZV2XK2L3HBq9sCKQiQ/MdhZJppH/rH0vddEAamsHUIs=
+github.com/aws/aws-sdk-go-v2/internal/v4a v1.4.3/go.mod h1:b9F9tk2HdHpbf3xbN7rUZcfmJI26N6NcJu/8OsBFI/0=
+github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.13.0 h1:6+lZi2JeGKtCraAj1rpoZfKqnQ9SptseRZioejfUOLM=
+github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.13.0/go.mod h1:eb3gfbVIxIoGgJsi9pGne19dhCBpK6opTYpQqAmdy44=
+github.com/aws/aws-sdk-go-v2/service/internal/checksum v1.8.3 h1:3ZKmesYBaFX33czDl6mbrcHb6jeheg6LqjJhQdefhsY=
+github.com/aws/aws-sdk-go-v2/service/internal/checksum v1.8.3/go.mod h1:7ryVb78GLCnjq7cw45N6oUb9REl7/vNUwjvIqC5UgdY=
+github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.13.3 h1:ieRzyHXypu5ByllM7Sp4hC5f/1Fy5wqxqY0yB85hC7s=
+github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.13.3/go.mod h1:O5ROz8jHiOAKAwx179v+7sHMhfobFVi6nZt8DEyiYoM=
+github.com/aws/aws-sdk-go-v2/service/internal/s3shared v1.19.3 h1:SE/e52dq9a05RuxzLcjT+S5ZpQobj3ie3UTaSf2NnZc=
+github.com/aws/aws-sdk-go-v2/service/internal/s3shared v1.19.3/go.mod h1:zkpvBTsR020VVr8TOrwK2TrUW9pOir28sH5ECHpnAfo=
+github.com/aws/aws-sdk-go-v2/service/s3 v1.87.0 h1:egoDf+Geuuntmw79Mz6mk9gGmELCPzg5PFEABOHB+6Y=
+github.com/aws/aws-sdk-go-v2/service/s3 v1.87.0/go.mod h1:t9MDi29H+HDbkolTSQtbI0HP9DemAWQzUjmWC7LGMnE=
+github.com/aws/aws-sdk-go-v2/service/sso v1.28.1 h1:YfsU8hHGvVT+c6Q8MUs8haDbFQajAImrB7yZ9XnPcBY=
+github.com/aws/aws-sdk-go-v2/service/sso v1.28.1/go.mod h1:iS5OmxEcN4QIPXARGhavH7S8kETNL11kym6jhoS7IUQ=
+github.com/aws/aws-sdk-go-v2/service/ssooidc v1.33.1 h1:b4REsk5C0hooowAPmV8fS2haHb+HCyb5FKSKOZRBBfU=
+github.com/aws/aws-sdk-go-v2/service/ssooidc v1.33.1/go.mod h1:59qHWaY5B+Rs7HGTuVGaC32m0rdpQ68N8QCN3khYiqs=
+github.com/aws/aws-sdk-go-v2/service/sts v1.37.1 h1:ssCHKyNJqTnqRH4Vlf+jI0brtGQYBvzWwnATsOMk1mk=
+github.com/aws/aws-sdk-go-v2/service/sts v1.37.1/go.mod h1:JdeBDPgpJfuS6rU/hNglmOigKhyEZtBmbraLE4GK1J8=
+github.com/aws/smithy-go v1.22.5 h1:P9ATCXPMb2mPjYBgueqJNCA5S9UfktsW0tTxi+a7eqw=
+github.com/aws/smithy-go v1.22.5/go.mod h1:t1ufH5HMublsJYulve2RKmHDC15xu1f26kHCp/HgceI=
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diff --git a/internal/api/handler.go b/internal/api/handler.go
new file mode 100644
index 0000000..c1448e6
--- /dev/null
+++ b/internal/api/handler.go
@@ -0,0 +1,392 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"log"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/DullJZ/s3-balance/internal/balancer"
+	"github.com/DullJZ/s3-balance/internal/bucket"
+	"github.com/DullJZ/s3-balance/internal/storage"
+	"github.com/DullJZ/s3-balance/pkg/presigner"
+	"github.com/gorilla/mux"
+)
+
+// Handler API处理器
+type Handler struct {
+	bucketManager *bucket.Manager
+	balancer      *balancer.Balancer
+	presigner     *presigner.Presigner
+	storage       *storage.Service
+}
+
+// NewHandler 创建新的API处理器
+func NewHandler(
+	bucketManager *bucket.Manager,
+	balancer *balancer.Balancer,
+	presigner *presigner.Presigner,
+	storage *storage.Service,
+) *Handler {
+	return &Handler{
+		bucketManager: bucketManager,
+		balancer:      balancer,
+		presigner:     presigner,
+		storage:       storage,
+	}
+}
+
+// RegisterRoutes 注册路由
+func (h *Handler) RegisterRoutes(router *mux.Router) {
+	// 健康检查
+	router.HandleFunc("/health", h.handleHealth).Methods("GET")
+	
+	// 存储桶状态
+	router.HandleFunc("/api/v1/buckets", h.handleListBuckets).Methods("GET")
+	router.HandleFunc("/api/v1/buckets/{bucket}/stats", h.handleBucketStats).Methods("GET")
+	
+	// 预签名URL生成
+	router.HandleFunc("/api/v1/presign/upload", h.handlePresignUpload).Methods("POST")
+	router.HandleFunc("/api/v1/presign/download", h.handlePresignDownload).Methods("POST")
+	router.HandleFunc("/api/v1/presign/delete", h.handlePresignDelete).Methods("POST")
+	router.HandleFunc("/api/v1/presign/multipart", h.handlePresignMultipart).Methods("POST")
+	
+	// 对象操作（记录元数据）
+	router.HandleFunc("/api/v1/objects", h.handleListObjects).Methods("GET")
+	router.HandleFunc("/api/v1/objects/{key:.*}", h.handleGetObjectInfo).Methods("GET")
+	router.HandleFunc("/api/v1/objects/{key:.*}", h.handleDeleteObject).Methods("DELETE")
+}
+
+// 健康检查
+func (h *Handler) handleHealth(w http.ResponseWriter, r *http.Request) {
+	response := map[string]interface{}{
+		"status": "healthy",
+		"time":   time.Now().Unix(),
+	}
+	h.sendJSON(w, http.StatusOK, response)
+}
+
+// 列出所有存储桶状态
+func (h *Handler) handleListBuckets(w http.ResponseWriter, r *http.Request) {
+	buckets := h.bucketManager.GetAllBuckets()
+	
+	var bucketList []map[string]interface{}
+	for _, b := range buckets {
+		bucketList = append(bucketList, map[string]interface{}{
+			"name":           b.Config.Name,
+			"endpoint":       b.Config.Endpoint,
+			"region":         b.Config.Region,
+			"max_size":       b.Config.MaxSize,
+			"max_size_bytes": b.Config.MaxSizeBytes,
+			"used_size":      b.GetUsedSize(),
+			"available":      b.IsAvailable(),
+			"weight":         b.Config.Weight,
+			"enabled":        b.Config.Enabled,
+		})
+	}
+	
+	h.sendJSON(w, http.StatusOK, map[string]interface{}{
+		"buckets":  bucketList,
+		"strategy": h.balancer.GetStrategy(),
+	})
+}
+
+// 获取单个存储桶统计
+func (h *Handler) handleBucketStats(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	bucketName := vars["bucket"]
+	
+	bucket, ok := h.bucketManager.GetBucket(bucketName)
+	if !ok {
+		h.sendError(w, http.StatusNotFound, "bucket not found")
+		return
+	}
+	
+	stats := map[string]interface{}{
+		"name":            bucket.Config.Name,
+		"max_size_bytes":  bucket.Config.MaxSizeBytes,
+		"used_size":       bucket.GetUsedSize(),
+		"available_space": bucket.GetAvailableSpace(),
+		"available":       bucket.IsAvailable(),
+		"last_checked":    bucket.LastChecked,
+	}
+	
+	h.sendJSON(w, http.StatusOK, stats)
+}
+
+// PresignUploadRequest 上传预签名请求
+type PresignUploadRequest struct {
+	Key         string            `json:"key"`
+	Size        int64            `json:"size"`
+	ContentType string            `json:"content_type,omitempty"`
+	Metadata    map[string]string `json:"metadata,omitempty"`
+}
+
+// 生成上传预签名URL
+func (h *Handler) handlePresignUpload(w http.ResponseWriter, r *http.Request) {
+	var req PresignUploadRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		h.sendError(w, http.StatusBadRequest, "invalid request body")
+		return
+	}
+	
+	if req.Key == "" {
+		h.sendError(w, http.StatusBadRequest, "key is required")
+		return
+	}
+	
+	// 选择存储桶
+	bucket, err := h.balancer.SelectBucket(req.Key, req.Size)
+	if err != nil {
+		h.sendError(w, http.StatusServiceUnavailable, err.Error())
+		return
+	}
+	
+	// 生成预签名URL
+	uploadURL, err := h.presigner.GenerateUploadURL(
+		context.Background(),
+		bucket,
+		req.Key,
+		req.ContentType,
+		req.Metadata,
+	)
+	if err != nil {
+		h.sendError(w, http.StatusInternalServerError, "failed to generate upload URL")
+		return
+	}
+	
+	// 记录对象元数据
+	if err := h.storage.RecordObject(req.Key, bucket.Config.Name, req.Size, req.Metadata); err != nil {
+		log.Printf("Failed to record object metadata: %v", err)
+	}
+	
+	// 更新存储桶使用量（预估）
+	bucket.UpdateUsedSize(req.Size)
+	
+	h.sendJSON(w, http.StatusOK, uploadURL)
+}
+
+// PresignDownloadRequest 下载预签名请求
+type PresignDownloadRequest struct {
+	Key string `json:"key"`
+}
+
+// 生成下载预签名URL
+func (h *Handler) handlePresignDownload(w http.ResponseWriter, r *http.Request) {
+	var req PresignDownloadRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		h.sendError(w, http.StatusBadRequest, "invalid request body")
+		return
+	}
+	
+	if req.Key == "" {
+		h.sendError(w, http.StatusBadRequest, "key is required")
+		return
+	}
+	
+	// 查找对象所在的存储桶
+	bucketName, err := h.storage.FindObjectBucket(req.Key)
+	if err != nil {
+		h.sendError(w, http.StatusNotFound, "object not found")
+		return
+	}
+	
+	bucket, ok := h.bucketManager.GetBucket(bucketName)
+	if !ok {
+		h.sendError(w, http.StatusNotFound, "bucket not found")
+		return
+	}
+	
+	// 生成预签名URL
+	downloadURL, err := h.presigner.GenerateDownloadURL(
+		context.Background(),
+		bucket,
+		req.Key,
+	)
+	if err != nil {
+		h.sendError(w, http.StatusInternalServerError, "failed to generate download URL")
+		return
+	}
+	
+	h.sendJSON(w, http.StatusOK, downloadURL)
+}
+
+// PresignDeleteRequest 删除预签名请求
+type PresignDeleteRequest struct {
+	Key string `json:"key"`
+}
+
+// 生成删除预签名URL
+func (h *Handler) handlePresignDelete(w http.ResponseWriter, r *http.Request) {
+	var req PresignDeleteRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		h.sendError(w, http.StatusBadRequest, "invalid request body")
+		return
+	}
+	
+	if req.Key == "" {
+		h.sendError(w, http.StatusBadRequest, "key is required")
+		return
+	}
+	
+	// 查找对象所在的存储桶
+	bucketName, err := h.storage.FindObjectBucket(req.Key)
+	if err != nil {
+		h.sendError(w, http.StatusNotFound, "object not found")
+		return
+	}
+	
+	bucket, ok := h.bucketManager.GetBucket(bucketName)
+	if !ok {
+		h.sendError(w, http.StatusNotFound, "bucket not found")
+		return
+	}
+	
+	// 生成预签名URL
+	deleteURL, err := h.presigner.GenerateDeleteURL(
+		context.Background(),
+		bucket,
+		req.Key,
+	)
+	if err != nil {
+		h.sendError(w, http.StatusInternalServerError, "failed to generate delete URL")
+		return
+	}
+	
+	h.sendJSON(w, http.StatusOK, deleteURL)
+}
+
+// PresignMultipartRequest 分片上传预签名请求
+type PresignMultipartRequest struct {
+	Key       string `json:"key"`
+	PartCount int    `json:"part_count"`
+	Size      int64  `json:"size"`
+}
+
+// 生成分片上传预签名URLs
+func (h *Handler) handlePresignMultipart(w http.ResponseWriter, r *http.Request) {
+	var req PresignMultipartRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		h.sendError(w, http.StatusBadRequest, "invalid request body")
+		return
+	}
+	
+	if req.Key == "" || req.PartCount <= 0 {
+		h.sendError(w, http.StatusBadRequest, "invalid parameters")
+		return
+	}
+	
+	// 选择存储桶
+	bucket, err := h.balancer.SelectBucket(req.Key, req.Size)
+	if err != nil {
+		h.sendError(w, http.StatusServiceUnavailable, err.Error())
+		return
+	}
+	
+	// 生成预签名URLs
+	multipartURLs, err := h.presigner.GenerateMultipartUploadURLs(
+		context.Background(),
+		bucket,
+		req.Key,
+		req.PartCount,
+	)
+	if err != nil {
+		h.sendError(w, http.StatusInternalServerError, "failed to generate multipart URLs")
+		return
+	}
+	
+	// 记录对象元数据
+	if err := h.storage.RecordObject(req.Key, bucket.Config.Name, req.Size, nil); err != nil {
+		log.Printf("Failed to record object metadata: %v", err)
+	}
+	
+	// 更新存储桶使用量（预估）
+	bucket.UpdateUsedSize(req.Size)
+	
+	h.sendJSON(w, http.StatusOK, multipartURLs)
+}
+
+// 列出对象
+func (h *Handler) handleListObjects(w http.ResponseWriter, r *http.Request) {
+	prefix := r.URL.Query().Get("prefix")
+	bucketName := r.URL.Query().Get("bucket")
+	marker := r.URL.Query().Get("marker")
+	limitStr := r.URL.Query().Get("limit")
+	
+	limit := 100
+	if limitStr != "" {
+		if l, err := strconv.Atoi(limitStr); err == nil && l > 0 {
+			limit = l
+		}
+	}
+	
+	// 调用更新后的ListObjects方法，传入所有必需的参数
+	objects, err := h.storage.ListObjects(bucketName, prefix, marker, limit)
+	if err != nil {
+		h.sendError(w, http.StatusInternalServerError, "failed to list objects")
+		return
+	}
+	
+	h.sendJSON(w, http.StatusOK, map[string]interface{}{
+		"objects": objects,
+		"count":   len(objects),
+	})
+}
+
+// 获取对象信息
+func (h *Handler) handleGetObjectInfo(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	key := vars["key"]
+	
+	info, err := h.storage.GetObjectInfo(key)
+	if err != nil {
+		h.sendError(w, http.StatusNotFound, "object not found")
+		return
+	}
+	
+	h.sendJSON(w, http.StatusOK, info)
+}
+
+// 删除对象（只删除元数据记录）
+func (h *Handler) handleDeleteObject(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	key := vars["key"]
+	
+	// 获取对象信息以更新存储桶使用量
+	info, err := h.storage.GetObjectInfo(key)
+	if err != nil {
+		h.sendError(w, http.StatusNotFound, "object not found")
+		return
+	}
+	
+	// 更新存储桶使用量
+	if bucket, ok := h.bucketManager.GetBucket(info.BucketName); ok {
+		bucket.UpdateUsedSize(-info.Size)
+	}
+	
+	// 删除元数据记录
+	if err := h.storage.DeleteObject(key); err != nil {
+		h.sendError(w, http.StatusInternalServerError, "failed to delete object")
+		return
+	}
+	
+	h.sendJSON(w, http.StatusOK, map[string]string{
+		"message": "object deleted successfully",
+	})
+}
+
+// 发送JSON响应
+func (h *Handler) sendJSON(w http.ResponseWriter, status int, data interface{}) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(data)
+}
+
+// 发送错误响应
+func (h *Handler) sendError(w http.ResponseWriter, status int, message string) {
+	h.sendJSON(w, status, map[string]string{
+		"error": message,
+	})
+}
diff --git a/internal/api/s3_handler.go b/internal/api/s3_handler.go
new file mode 100644
index 0000000..c50ec49
--- /dev/null
+++ b/internal/api/s3_handler.go
@@ -0,0 +1,780 @@
+package api
+
+import (
+	"context"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/DullJZ/s3-balance/internal/balancer"
+	"github.com/DullJZ/s3-balance/internal/bucket"
+	"github.com/DullJZ/s3-balance/internal/storage"
+	"github.com/DullJZ/s3-balance/pkg/presigner"
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+	"github.com/aws/aws-sdk-go-v2/service/s3/types"
+	"github.com/gorilla/mux"
+)
+
+// S3Handler S3兼容的API处理器
+type S3Handler struct {
+	bucketManager *bucket.Manager
+	balancer      *balancer.Balancer
+	presigner     *presigner.Presigner
+	storage       *storage.Service
+	accessKey     string
+	secretKey     string
+}
+
+// NewS3Handler 创建新的S3兼容API处理器
+func NewS3Handler(
+	bucketManager *bucket.Manager,
+	balancer *balancer.Balancer,
+	presigner *presigner.Presigner,
+	storage *storage.Service,
+	accessKey string,
+	secretKey string,
+) *S3Handler {
+	return &S3Handler{
+		bucketManager: bucketManager,
+		balancer:      balancer,
+		presigner:     presigner,
+		storage:       storage,
+		accessKey:     accessKey,
+		secretKey:     secretKey,
+	}
+}
+
+// RegisterS3Routes 注册S3兼容的路由
+func (h *S3Handler) RegisterS3Routes(router *mux.Router) {
+	// Service operations
+	router.HandleFunc("/", h.handleListBuckets).Methods("GET")
+	
+	// Bucket operations
+	router.HandleFunc("/{bucket}", h.handleBucketOperations).Methods("GET", "HEAD", "PUT", "DELETE")
+	
+	// Object operations
+	router.HandleFunc("/{bucket}/{key:.*}", h.handleObjectOperations).Methods("GET", "HEAD", "PUT", "DELETE")
+	
+	// Multipart upload operations
+	router.HandleFunc("/{bucket}/{key:.*}", h.handleMultipartUpload).Methods("POST").Queries("uploads", "")
+	router.HandleFunc("/{bucket}/{key:.*}", h.handleListMultipartUploads).Methods("GET").Queries("uploads", "")
+	router.HandleFunc("/{bucket}/{key:.*}", h.handleListMultipartParts).Methods("GET").Queries("uploadId", "")
+	router.HandleFunc("/{bucket}/{key:.*}", h.handleCompleteMultipartUpload).Methods("POST").Queries("uploadId", "")
+	router.HandleFunc("/{bucket}/{key:.*}", h.handleAbortMultipartUpload).Methods("DELETE").Queries("uploadId", "")
+	
+	// 添加认证中间件
+	router.Use(h.s3AuthMiddleware)
+}
+
+// S3 XML响应结构体定义
+type ListBucketsResult struct {
+	XMLName xml.Name `xml:"ListAllMyBucketsResult"`
+	Xmlns   string   `xml:"xmlns,attr"`
+	Owner   Owner    `xml:"Owner"`
+	Buckets Buckets  `xml:"Buckets"`
+}
+
+type Owner struct {
+	ID          string `xml:"ID"`
+	DisplayName string `xml:"DisplayName"`
+}
+
+type Buckets struct {
+	Bucket []BucketInfo `xml:"Bucket"`
+}
+
+type BucketInfo struct {
+	Name         string    `xml:"Name"`
+	CreationDate time.Time `xml:"CreationDate"`
+}
+
+type ListBucketResult struct {
+	XMLName        xml.Name       `xml:"ListBucketResult"`
+	Xmlns          string         `xml:"xmlns,attr"`
+	Name           string         `xml:"Name"`
+	Prefix         string         `xml:"Prefix"`
+	Marker         string         `xml:"Marker"`
+	MaxKeys        int            `xml:"MaxKeys"`
+	IsTruncated    bool           `xml:"IsTruncated"`
+	Contents       []ObjectInfo   `xml:"Contents"`
+	CommonPrefixes []CommonPrefix `xml:"CommonPrefixes,omitempty"`
+}
+
+type ObjectInfo struct {
+	Key          string    `xml:"Key"`
+	LastModified time.Time `xml:"LastModified"`
+	ETag         string    `xml:"ETag"`
+	Size         int64     `xml:"Size"`
+	StorageClass string    `xml:"StorageClass"`
+	Owner        Owner     `xml:"Owner"`
+}
+
+type CommonPrefix struct {
+	Prefix string `xml:"Prefix"`
+}
+
+type InitiateMultipartUploadResult struct {
+	XMLName   xml.Name `xml:"InitiateMultipartUploadResult"`
+	Xmlns     string   `xml:"xmlns,attr"`
+	Bucket    string   `xml:"Bucket"`
+	Key       string   `xml:"Key"`
+	UploadID  string   `xml:"UploadId"`
+}
+
+type ListMultipartUploadsResult struct {
+	XMLName          xml.Name              `xml:"ListMultipartUploadsResult"`
+	Xmlns            string                `xml:"xmlns,attr"`
+	Bucket           string                `xml:"Bucket"`
+	KeyMarker        string                `xml:"KeyMarker"`
+	UploadIdMarker   string                `xml:"UploadIdMarker"`
+	NextKeyMarker    string                `xml:"NextKeyMarker"`
+	NextUploadIdMarker string              `xml:"NextUploadIdMarker"`
+	MaxUploads      int                   `xml:"MaxUploads"`
+	IsTruncated     bool                  `xml:"IsTruncated"`
+	Uploads         []Upload              `xml:"Upload"`
+	CommonPrefixes   []CommonPrefix        `xml:"CommonPrefixes,omitempty"`
+}
+
+type Upload struct {
+	Key       string    `xml:"Key"`
+	UploadID  string    `xml:"UploadId"`
+	Initiator Owner      `xml:"Initiator"`
+	Owner     Owner      `xml:"Owner"`
+	StorageClass string   `xml:"StorageClass"`
+	Initiated time.Time `xml:"Initiated"`
+}
+
+type ListPartsResult struct {
+	XMLName          xml.Name `xml:"ListPartsResult"`
+	Xmlns            string   `xml:"xmlns,attr"`
+	Bucket           string   `xml:"Bucket"`
+	Key              string   `xml:"Key"`
+	UploadID         string   `xml:"UploadId"`
+	PartNumberMarker int      `xml:"PartNumberMarker"`
+	NextPartNumberMarker int   `xml:"NextPartNumberMarker"`
+	MaxParts         int      `xml:"MaxParts"`
+	IsTruncated      bool     `xml:"IsTruncated"`
+	Parts            []Part   `xml:"Part"`
+}
+
+type Part struct {
+	PartNumber   int       `xml:"PartNumber"`
+	LastModified time.Time `xml:"LastModified"`
+	ETag        string    `xml:"ETag"`
+	Size        int64     `xml:"Size"`
+}
+
+type CompleteMultipartUpload struct {
+	XMLName xml.Name `xml:"CompleteMultipartUpload"`
+	Parts   []Part   `xml:"Part"`
+}
+
+type CompleteMultipartUploadResult struct {
+	XMLName  xml.Name `xml:"CompleteMultipartUploadResult"`
+	Xmlns    string   `xml:"xmlns,attr"`
+	Location string   `xml:"Location"`
+	Bucket   string   `xml:"Bucket"`
+	Key      string   `xml:"Key"`
+	ETag     string   `xml:"ETag"`
+}
+
+type ErrorResponse struct {
+	XMLName   xml.Name `xml:"Error"`
+	Code      string   `xml:"Code"`
+	Message   string   `xml:"Message"`
+	Resource  string   `xml:"Resource"`
+	RequestID string   `xml:"RequestId"`
+}
+
+// s3AuthMiddleware S3认证中间件（简化版）
+func (h *S3Handler) s3AuthMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// 简化的认证实现，实际应该验证AWS Signature
+		// 这里只做基本的header检查
+		authHeader := r.Header.Get("Authorization")
+		if authHeader == "" {
+			// 允许匿名访问（用于测试）
+			// 在生产环境中应该要求认证
+		}
+		
+		next.ServeHTTP(w, r)
+	})
+}
+
+// handleListBuckets 处理列出所有存储桶请求
+func (h *S3Handler) handleListBuckets(w http.ResponseWriter, r *http.Request) {
+	buckets := h.bucketManager.GetAllBuckets()
+	
+	result := ListBucketsResult{
+		Xmlns: "http://s3.amazonaws.com/doc/2006-03-01/",
+		Owner: Owner{
+			ID:          "s3-balance",
+			DisplayName: "S3 Balance Service",
+		},
+		Buckets: Buckets{
+			Bucket: make([]BucketInfo, 0, len(buckets)),
+		},
+	}
+	
+	for _, b := range buckets {
+		if b.IsAvailable() {
+			result.Buckets.Bucket = append(result.Buckets.Bucket, BucketInfo{
+				Name:         b.Config.Name,
+				CreationDate: time.Now().Add(-24 * time.Hour), // 模拟创建时间
+			})
+		}
+	}
+	
+	h.sendXMLResponse(w, http.StatusOK, result)
+}
+
+// handleBucketOperations 处理存储桶相关操作
+func (h *S3Handler) handleBucketOperations(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	bucketName := vars["bucket"]
+	
+	switch r.Method {
+	case "GET":
+		h.handleListObjects(w, r, bucketName)
+	case "HEAD":
+		h.handleHeadBucket(w, r, bucketName)
+	case "PUT":
+		h.handleCreateBucket(w, r, bucketName)
+	case "DELETE":
+		h.handleDeleteBucket(w, r, bucketName)
+	}
+}
+
+// handleListObjects 列出存储桶中的对象
+func (h *S3Handler) handleListObjects(w http.ResponseWriter, r *http.Request, bucketName string) {
+	// 检查bucket是否存在
+	if _, ok := h.bucketManager.GetBucket(bucketName); !ok {
+		h.sendS3Error(w, "NoSuchBucket", "The specified bucket does not exist", bucketName)
+		return
+	}
+	
+	// 解析查询参数
+	prefix := r.URL.Query().Get("prefix")
+	marker := r.URL.Query().Get("marker")
+	maxKeysStr := r.URL.Query().Get("max-keys")
+	delimiter := r.URL.Query().Get("delimiter")
+	
+	maxKeys := 1000
+	if maxKeysStr != "" {
+		if mk, err := strconv.Atoi(maxKeysStr); err == nil {
+			maxKeys = mk
+		}
+	}
+	
+	// 从存储中获取对象列表
+	objects, err := h.storage.ListObjects(bucketName, prefix, marker, maxKeys)
+	if err != nil {
+		h.sendS3Error(w, "InternalError", "Internal server error", bucketName)
+		return
+	}
+	
+	result := ListBucketResult{
+		Xmlns:       "http://s3.amazonaws.com/doc/2006-03-01/",
+		Name:        bucketName,
+		Prefix:      prefix,
+		Marker:      marker,
+		MaxKeys:     maxKeys,
+		IsTruncated: false, // 简化实现
+		Contents:    make([]ObjectInfo, 0),
+	}
+	
+	// 处理分隔符逻辑
+	if delimiter != "" {
+		// 简化的分隔符处理
+		result.CommonPrefixes = make([]CommonPrefix, 0)
+	}
+	
+	for _, obj := range objects {
+		result.Contents = append(result.Contents, ObjectInfo{
+			Key:          obj.Key,
+			LastModified: obj.UpdatedAt,
+			ETag:         fmt.Sprintf("\"%x\"", obj.ID), // 简化的ETag
+			Size:         obj.Size,
+			StorageClass: "STANDARD",
+			Owner: Owner{
+				ID:          "s3-balance",
+				DisplayName: "S3 Balance Service",
+			},
+		})
+	}
+	
+	h.sendXMLResponse(w, http.StatusOK, result)
+}
+
+// handleHeadBucket 检查存储桶是否存在
+func (h *S3Handler) handleHeadBucket(w http.ResponseWriter, r *http.Request, bucketName string) {
+	if _, ok := h.bucketManager.GetBucket(bucketName); !ok {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+	
+	w.WriteHeader(http.StatusOK)
+}
+
+// handleCreateBucket 创建存储桶（虚拟实现）
+func (h *S3Handler) handleCreateBucket(w http.ResponseWriter, r *http.Request, bucketName string) {
+	// 在负载均衡场景下，不真正创建bucket，只返回成功
+	// 实际的bucket应该在配置中预先定义
+	w.Header().Set("Location", "/" + bucketName)
+	w.WriteHeader(http.StatusOK)
+}
+
+// handleDeleteBucket 删除存储桶（虚拟实现）
+func (h *S3Handler) handleDeleteBucket(w http.ResponseWriter, r *http.Request, bucketName string) {
+	// 在负载均衡场景下，不真正删除bucket
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// handleObjectOperations 处理对象相关操作
+func (h *S3Handler) handleObjectOperations(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	bucketName := vars["bucket"]
+	key := vars["key"]
+	
+	switch r.Method {
+	case "GET":
+		h.handleGetObject(w, r, bucketName, key)
+	case "HEAD":
+		h.handleHeadObject(w, r, bucketName, key)
+	case "PUT":
+		h.handlePutObject(w, r, bucketName, key)
+	case "DELETE":
+		h.handleDeleteObject(w, r, bucketName, key)
+	}
+}
+
+// handleGetObject 获取对象（默认使用预签名URL重定向）
+func (h *S3Handler) handleGetObject(w http.ResponseWriter, r *http.Request, bucketName string, key string) {
+	// 查找对象所在的实际存储桶
+	actualBucketName, err := h.storage.FindObjectBucket(key)
+	if err != nil {
+		h.sendS3Error(w, "NoSuchKey", "The specified key does not exist", key)
+		return
+	}
+	
+	bucket, ok := h.bucketManager.GetBucket(actualBucketName)
+	if !ok {
+		h.sendS3Error(w, "InternalError", "Internal server error", bucketName)
+		return
+	}
+	
+	// 生成预签名下载URL
+	downloadInfo, err := h.presigner.GenerateDownloadURL(
+		context.Background(),
+		bucket,
+		key,
+	)
+	if err != nil {
+		h.sendS3Error(w, "InternalError", "Failed to generate download URL", key)
+		return
+	}
+	
+	// 默认使用预签名重定向模式，只有明确指定时才使用代理模式
+	if r.URL.Query().Get("proxy") == "true" {
+		// 代理模式：服务器下载内容并返回给客户端
+		resp, err := http.Get(downloadInfo.URL)
+		if err != nil {
+			h.sendS3Error(w, "InternalError", "Failed to fetch object", key)
+			return
+		}
+		defer resp.Body.Close()
+		
+		// 复制响应头
+		for k, v := range resp.Header {
+			w.Header()[k] = v
+		}
+		
+		// 复制响应体
+		io.Copy(w, resp.Body)
+	} else {
+		// 重定向模式：返回302重定向到预签名URL（默认）
+		http.Redirect(w, r, downloadInfo.URL, http.StatusFound)
+	}
+}
+
+// handleHeadObject 获取对象元数据
+func (h *S3Handler) handleHeadObject(w http.ResponseWriter, r *http.Request, bucketName string, key string) {
+	// 从存储中获取对象信息
+	obj, err := h.storage.GetObjectInfo(key)
+	if err != nil {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+	
+	w.Header().Set("Content-Length", strconv.FormatInt(obj.Size, 10))
+	w.Header().Set("Last-Modified", obj.UpdatedAt.Format(http.TimeFormat))
+	w.Header().Set("ETag", fmt.Sprintf("\"%x\"", obj.ID))
+	w.Header().Set("Content-Type", "application/octet-stream")
+	w.WriteHeader(http.StatusOK)
+}
+
+// handlePutObject 上传对象（默认使用预签名URL重定向）
+func (h *S3Handler) handlePutObject(w http.ResponseWriter, r *http.Request, bucketName string, key string) {
+	// 获取内容长度
+	contentLength := r.ContentLength
+	if contentLength < 0 {
+		h.sendS3Error(w, "MissingContentLength", "Content-Length header is required", key)
+		return
+	}
+	
+	// 选择目标存储桶
+	targetBucket, err := h.balancer.SelectBucket(key, contentLength)
+	if err != nil {
+		h.sendS3Error(w, "InsufficientStorage", "No bucket has enough space", key)
+		return
+	}
+	
+	// 生成预签名上传URL
+	uploadInfo, err := h.presigner.GenerateUploadURL(
+		context.Background(),
+		targetBucket,
+		key,
+		r.Header.Get("Content-Type"),
+		nil, // metadata
+	)
+	if err != nil {
+		h.sendS3Error(w, "InternalError", "Failed to generate upload URL", key)
+		return
+	}
+	
+	// 默认使用预签名重定向模式，只有明确指定时才使用代理模式
+	if r.URL.Query().Get("proxy") == "true" {
+		// 代理模式：读取请求体并上传到预签名URL
+		// 创建新的请求
+		req, err := http.NewRequest(uploadInfo.Method, uploadInfo.URL, r.Body)
+		if err != nil {
+			h.sendS3Error(w, "InternalError", "Failed to create upload request", key)
+			return
+		}
+		
+		// 设置必要的头
+		req.ContentLength = contentLength
+		if ct := r.Header.Get("Content-Type"); ct != "" {
+			req.Header.Set("Content-Type", ct)
+		}
+		
+		// 添加预签名URL所需的额外头
+		for k, v := range uploadInfo.Headers {
+			req.Header.Set(k, v)
+		}
+		
+		// 执行上传
+		client := &http.Client{Timeout: 30 * time.Minute}
+		resp, err := client.Do(req)
+		if err != nil {
+			h.sendS3Error(w, "InternalError", "Failed to upload object", key)
+			return
+		}
+		defer resp.Body.Close()
+		
+		if resp.StatusCode >= 200 && resp.StatusCode < 300 {
+			// 记录对象元数据
+			h.storage.RecordObject(key, targetBucket.Config.Name, contentLength, nil)
+			targetBucket.UpdateUsedSize(contentLength)
+			
+			// 返回成功响应
+			w.Header().Set("ETag", fmt.Sprintf("\"%x\"", time.Now().UnixNano()))
+			w.WriteHeader(http.StatusOK)
+		} else {
+			h.sendS3Error(w, "InternalError", "Upload failed", key)
+		}
+	} else {
+		// 重定向模式：返回307临时重定向让客户端直接上传（默认）
+		w.Header().Set("Location", uploadInfo.URL)
+		w.WriteHeader(http.StatusTemporaryRedirect)
+	}
+}
+
+// handleDeleteObject 删除对象
+func (h *S3Handler) handleDeleteObject(w http.ResponseWriter, r *http.Request, bucketName string, key string) {
+	// 查找对象所在的实际存储桶
+	actualBucketName, err := h.storage.FindObjectBucket(key)
+	if err != nil {
+		// 对象不存在，S3规范要求返回204
+		w.WriteHeader(http.StatusNoContent)
+		return
+	}
+	
+	bucket, ok := h.bucketManager.GetBucket(actualBucketName)
+	if !ok {
+		h.sendS3Error(w, "InternalError", "Internal server error", bucketName)
+		return
+	}
+	
+	// 生成预签名删除URL
+	deleteInfo, err := h.presigner.GenerateDeleteURL(
+		context.Background(),
+		bucket,
+		key,
+	)
+	if err != nil {
+		h.sendS3Error(w, "InternalError", "Failed to generate delete URL", key)
+		return
+	}
+	
+	// 执行删除
+	req, _ := http.NewRequest("DELETE", deleteInfo.URL, nil)
+	client := &http.Client{Timeout: 30 * time.Second}
+	resp, err := client.Do(req)
+	if err != nil {
+		h.sendS3Error(w, "InternalError", "Failed to delete object", key)
+		return
+	}
+	defer resp.Body.Close()
+	
+	// 从数据库中删除对象记录
+	h.storage.DeleteObject(key)
+	
+	// S3规范要求删除操作总是返回204
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// handleMultipartUpload 初始化分片上传
+func (h *S3Handler) handleMultipartUpload(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	key := vars["key"]
+	
+	// 选择目标存储桶
+	targetBucket, err := h.balancer.SelectBucket(key, 0) // 分片上传时不检查空间
+	if err != nil {
+		h.sendS3Error(w, "InternalError", "Failed to select bucket for upload", key)
+		return
+	}
+	
+	// 初始化分片上传
+	ctx := context.Background()
+	createResp, err := targetBucket.Client.CreateMultipartUpload(ctx, &s3.CreateMultipartUploadInput{
+		Bucket: aws.String(targetBucket.Config.Name),
+		Key:    aws.String(key),
+	})
+	if err != nil {
+		h.sendS3Error(w, "InternalError", "Failed to initiate multipart upload", key)
+		return
+	}
+	
+	result := InitiateMultipartUploadResult{
+		Xmlns:    "http://s3.amazonaws.com/doc/2006-03-01/",
+		Bucket:   targetBucket.Config.Name,
+		Key:      key,
+		UploadID: *createResp.UploadId,
+	}
+	
+	h.sendXMLResponse(w, http.StatusOK, result)
+}
+
+// handleListMultipartUploads 列出分片上传
+func (h *S3Handler) handleListMultipartUploads(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	bucketName := vars["bucket"]
+	key := vars["key"]
+	
+	// 检查bucket是否存在
+	if _, ok := h.bucketManager.GetBucket(bucketName); !ok {
+		h.sendS3Error(w, "NoSuchBucket", "The specified bucket does not exist", bucketName)
+		return
+	}
+	
+	// 简化实现：返回空列表
+	result := ListMultipartUploadsResult{
+		Xmlns:       "http://s3.amazonaws.com/doc/2006-03-01/",
+		Bucket:      bucketName,
+		KeyMarker:   key,
+		MaxUploads:  1000,
+		IsTruncated: false,
+		Uploads:     make([]Upload, 0),
+	}
+	
+	h.sendXMLResponse(w, http.StatusOK, result)
+}
+
+// handleListMultipartParts 列出分片上传的分片
+func (h *S3Handler) handleListMultipartParts(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	bucketName := vars["bucket"]
+	key := vars["key"]
+	uploadID := r.URL.Query().Get("uploadId")
+	
+	// 检查bucket是否存在
+	if _, ok := h.bucketManager.GetBucket(bucketName); !ok {
+		h.sendS3Error(w, "NoSuchBucket", "The specified bucket does not exist", bucketName)
+		return
+	}
+	
+	// 简化实现：返回空列表
+	result := ListPartsResult{
+		Xmlns:             "http://s3.amazonaws.com/doc/2006-03-01/",
+		Bucket:            bucketName,
+		Key:               key,
+		UploadID:          uploadID,
+		PartNumberMarker:  0,
+		MaxParts:          1000,
+		IsTruncated:       false,
+		Parts:             make([]Part, 0),
+	}
+	
+	h.sendXMLResponse(w, http.StatusOK, result)
+}
+
+// handleCompleteMultipartUpload 完成分片上传
+func (h *S3Handler) handleCompleteMultipartUpload(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	bucketName := vars["bucket"]
+	key := vars["key"]
+	uploadID := r.URL.Query().Get("uploadId")
+	
+	// 查找对象所在的实际存储桶（简化实现，使用配置的bucket）
+	bucket, ok := h.bucketManager.GetBucket(bucketName)
+	if !ok {
+		h.sendS3Error(w, "NoSuchBucket", "The specified bucket does not exist", bucketName)
+		return
+	}
+	
+	// 解析请求体以获取分片列表
+	var completeReq CompleteMultipartUpload
+	body, _ := io.ReadAll(r.Body)
+	xml.Unmarshal(body, &completeReq)
+	
+	// 完成分片上传
+	ctx := context.Background()
+	var parts []types.CompletedPart
+	for _, part := range completeReq.Parts {
+		parts = append(parts, types.CompletedPart{
+			ETag:       aws.String(part.ETag),
+			PartNumber: aws.Int32(int32(part.PartNumber)),
+		})
+	}
+	
+	completeResp, err := bucket.Client.CompleteMultipartUpload(ctx, &s3.CompleteMultipartUploadInput{
+		Bucket:   aws.String(bucket.Config.Name),
+		Key:      aws.String(key),
+		UploadId: aws.String(uploadID),
+		MultipartUpload: &types.CompletedMultipartUpload{
+			Parts: parts,
+		},
+	})
+	if err != nil {
+		h.sendS3Error(w, "InternalError", "Failed to complete multipart upload", key)
+		return
+	}
+	
+	result := CompleteMultipartUploadResult{
+		Xmlns:    "http://s3.amazonaws.com/doc/2006-03-01/",
+		Location:  "/" + bucket.Config.Name + "/" + key,
+		Bucket:   bucket.Config.Name,
+		Key:      key,
+		ETag:     *completeResp.ETag,
+	}
+	
+	// 记录对象元数据（简化：假设总大小）
+	h.storage.RecordObject(key, bucket.Config.Name, 0, nil)
+	
+	h.sendXMLResponse(w, http.StatusOK, result)
+}
+
+// handleAbortMultipartUpload 中止分片上传
+func (h *S3Handler) handleAbortMultipartUpload(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	bucketName := vars["bucket"]
+	key := vars["key"]
+	uploadID := r.URL.Query().Get("uploadId")
+	
+	// 查找对象所在的实际存储桶（简化实现，使用配置的bucket）
+	bucket, ok := h.bucketManager.GetBucket(bucketName)
+	if !ok {
+		h.sendS3Error(w, "NoSuchBucket", "The specified bucket does not exist", bucketName)
+		return
+	}
+	
+	// 中止分片上传
+	ctx := context.Background()
+	_, err := bucket.Client.AbortMultipartUpload(ctx, &s3.AbortMultipartUploadInput{
+		Bucket:   aws.String(bucket.Config.Name),
+		Key:      aws.String(key),
+		UploadId: aws.String(uploadID),
+	})
+	if err != nil {
+		h.sendS3Error(w, "InternalError", "Failed to abort multipart upload", key)
+		return
+	}
+	
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// sendXMLResponse 发送XML响应
+func (h *S3Handler) sendXMLResponse(w http.ResponseWriter, statusCode int, data interface{}) {
+	w.Header().Set("Content-Type", "application/xml")
+	w.WriteHeader(statusCode)
+	
+	encoder := xml.NewEncoder(w)
+	encoder.Indent("", "  ")
+	
+	// 写入XML声明
+	w.Write([]byte(xml.Header))
+	
+	if err := encoder.Encode(data); err != nil {
+		// 如果编码失败，记录错误
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+	}
+}
+
+// sendS3Error 发送S3错误响应
+func (h *S3Handler) sendS3Error(w http.ResponseWriter, code string, message string, resource string) {
+	errorResp := ErrorResponse{
+		Code:      code,
+		Message:   message,
+		Resource:  resource,
+		RequestID: fmt.Sprintf("%d", time.Now().UnixNano()),
+	}
+	
+	statusCode := http.StatusBadRequest
+	switch code {
+	case "NoSuchBucket", "NoSuchKey":
+		statusCode = http.StatusNotFound
+	case "BucketAlreadyExists":
+		statusCode = http.StatusConflict
+	case "InvalidAccessKeyId", "SignatureDoesNotMatch":
+		statusCode = http.StatusForbidden
+	case "InternalError":
+		statusCode = http.StatusInternalServerError
+	case "InsufficientStorage":
+		statusCode = http.StatusInsufficientStorage
+	}
+	
+	h.sendXMLResponse(w, statusCode, errorResp)
+}
+
+// 辅助函数：解析S3路径
+func parseS3Path(requestPath string) (bucket string, key string) {
+	requestPath = strings.TrimPrefix(requestPath, "/")
+	parts := strings.SplitN(requestPath, "/", 2)
+	
+	if len(parts) > 0 {
+		bucket = parts[0]
+	}
+	if len(parts) > 1 {
+		key = parts[1]
+	}
+	
+	return bucket, key
+}
+
+// 辅助函数：URL编码/解码
+func urlEncodePath(p string) string {
+	return strings.ReplaceAll(url.QueryEscape(p), "+", "%20")
+}
+
+func urlDecodePath(p string) string {
+	decoded, _ := url.QueryUnescape(p)
+	return decoded
+}
diff --git a/internal/balancer/balancer.go b/internal/balancer/balancer.go
new file mode 100644
index 0000000..8b3d508
--- /dev/null
+++ b/internal/balancer/balancer.go
@@ -0,0 +1,264 @@
+package balancer
+
+import (
+	"crypto/md5"
+	"encoding/binary"
+	"fmt"
+	"math/rand"
+	"sort"
+	"sync"
+	"sync/atomic"
+
+	"github.com/DullJZ/s3-balance/internal/bucket"
+	"github.com/DullJZ/s3-balance/internal/config"
+)
+
+// Strategy 负载均衡策略接口
+type Strategy interface {
+	SelectBucket(buckets []*bucket.BucketInfo, key string, size int64) (*bucket.BucketInfo, error)
+	Name() string
+}
+
+// Balancer 负载均衡器
+type Balancer struct {
+	manager  *bucket.Manager
+	strategy Strategy
+	config   *config.BalancerConfig
+}
+
+// NewBalancer 创建新的负载均衡器
+func NewBalancer(manager *bucket.Manager, cfg *config.BalancerConfig) (*Balancer, error) {
+	var strategy Strategy
+	
+	switch cfg.Strategy {
+	case "round-robin":
+		strategy = NewRoundRobinStrategy()
+	case "least-space":
+		strategy = NewLeastSpaceStrategy()
+	case "weighted":
+		strategy = NewWeightedStrategy()
+	case "consistent-hash":
+		strategy = NewConsistentHashStrategy()
+	default:
+		return nil, fmt.Errorf("unknown balancer strategy: %s", cfg.Strategy)
+	}
+
+	return &Balancer{
+		manager:  manager,
+		strategy: strategy,
+		config:   cfg,
+	}, nil
+}
+
+// SelectBucket 选择一个存储桶
+func (b *Balancer) SelectBucket(key string, size int64) (*bucket.BucketInfo, error) {
+	// 获取所有可用的存储桶
+	buckets := b.manager.GetAvailableBuckets()
+	if len(buckets) == 0 {
+		return nil, fmt.Errorf("no available buckets")
+	}
+
+	// 过滤出有足够空间的存储桶
+	var availableBuckets []*bucket.BucketInfo
+	for _, bucket := range buckets {
+		if bucket.GetAvailableSpace() >= size {
+			availableBuckets = append(availableBuckets, bucket)
+		}
+	}
+
+	if len(availableBuckets) == 0 {
+		return nil, fmt.Errorf("no bucket has enough space for %d bytes", size)
+	}
+
+	// 使用策略选择存储桶
+	selected, err := b.strategy.SelectBucket(availableBuckets, key, size)
+	if err != nil {
+		return nil, err
+	}
+
+	return selected, nil
+}
+
+// GetStrategy 获取当前策略名称
+func (b *Balancer) GetStrategy() string {
+	return b.strategy.Name()
+}
+
+// RoundRobinStrategy 轮询策略
+type RoundRobinStrategy struct {
+	counter uint64
+}
+
+// NewRoundRobinStrategy 创建轮询策略
+func NewRoundRobinStrategy() *RoundRobinStrategy {
+	return &RoundRobinStrategy{}
+}
+
+// SelectBucket 选择存储桶（轮询）
+func (s *RoundRobinStrategy) SelectBucket(buckets []*bucket.BucketInfo, key string, size int64) (*bucket.BucketInfo, error) {
+	if len(buckets) == 0 {
+		return nil, fmt.Errorf("no buckets available")
+	}
+	
+	index := atomic.AddUint64(&s.counter, 1) % uint64(len(buckets))
+	return buckets[index], nil
+}
+
+// Name 返回策略名称
+func (s *RoundRobinStrategy) Name() string {
+	return "round-robin"
+}
+
+// LeastSpaceStrategy 最少使用空间策略
+type LeastSpaceStrategy struct{}
+
+// NewLeastSpaceStrategy 创建最少使用空间策略
+func NewLeastSpaceStrategy() *LeastSpaceStrategy {
+	return &LeastSpaceStrategy{}
+}
+
+// SelectBucket 选择存储桶（选择使用空间最少的）
+func (s *LeastSpaceStrategy) SelectBucket(buckets []*bucket.BucketInfo, key string, size int64) (*bucket.BucketInfo, error) {
+	if len(buckets) == 0 {
+		return nil, fmt.Errorf("no buckets available")
+	}
+
+	// 按可用空间排序（从大到小）
+	sort.Slice(buckets, func(i, j int) bool {
+		return buckets[i].GetAvailableSpace() > buckets[j].GetAvailableSpace()
+	})
+
+	return buckets[0], nil
+}
+
+// Name 返回策略名称
+func (s *LeastSpaceStrategy) Name() string {
+	return "least-space"
+}
+
+// WeightedStrategy 加权策略
+type WeightedStrategy struct {
+	mu sync.RWMutex
+}
+
+// NewWeightedStrategy 创建加权策略
+func NewWeightedStrategy() *WeightedStrategy {
+	return &WeightedStrategy{}
+}
+
+// SelectBucket 选择存储桶（基于权重）
+func (s *WeightedStrategy) SelectBucket(buckets []*bucket.BucketInfo, key string, size int64) (*bucket.BucketInfo, error) {
+	if len(buckets) == 0 {
+		return nil, fmt.Errorf("no buckets available")
+	}
+
+	// 计算总权重
+	totalWeight := 0
+	for _, b := range buckets {
+		totalWeight += b.Config.Weight
+	}
+
+	if totalWeight == 0 {
+		// 如果所有权重都是0，则随机选择
+		return buckets[rand.Intn(len(buckets))], nil
+	}
+
+	// 根据权重随机选择
+	randomWeight := rand.Intn(totalWeight)
+	currentWeight := 0
+
+	for _, b := range buckets {
+		currentWeight += b.Config.Weight
+		if randomWeight < currentWeight {
+			return b, nil
+		}
+	}
+
+	// 不应该到达这里，但为了安全返回最后一个
+	return buckets[len(buckets)-1], nil
+}
+
+// Name 返回策略名称
+func (s *WeightedStrategy) Name() string {
+	return "weighted"
+}
+
+// ConsistentHashStrategy 一致性哈希策略
+type ConsistentHashStrategy struct {
+	replicas int
+	ring     map[uint32]*bucket.BucketInfo
+	nodes    []uint32
+	mu       sync.RWMutex
+}
+
+// NewConsistentHashStrategy 创建一致性哈希策略
+func NewConsistentHashStrategy() *ConsistentHashStrategy {
+	return &ConsistentHashStrategy{
+		replicas: 100, // 每个节点的虚拟节点数
+		ring:     make(map[uint32]*bucket.BucketInfo),
+	}
+}
+
+// SelectBucket 选择存储桶（基于一致性哈希）
+func (s *ConsistentHashStrategy) SelectBucket(buckets []*bucket.BucketInfo, key string, size int64) (*bucket.BucketInfo, error) {
+	if len(buckets) == 0 {
+		return nil, fmt.Errorf("no buckets available")
+	}
+
+	// 更新哈希环
+	s.updateRing(buckets)
+
+	// 计算key的哈希值
+	hash := s.hash(key)
+
+	// 在环上找到第一个大于等于hash的节点
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	idx := sort.Search(len(s.nodes), func(i int) bool {
+		return s.nodes[i] >= hash
+	})
+
+	// 如果没找到，返回第一个节点（环形结构）
+	if idx == len(s.nodes) {
+		idx = 0
+	}
+
+	return s.ring[s.nodes[idx]], nil
+}
+
+// updateRing 更新哈希环
+func (s *ConsistentHashStrategy) updateRing(buckets []*bucket.BucketInfo) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	// 清空现有环
+	s.ring = make(map[uint32]*bucket.BucketInfo)
+	s.nodes = nil
+
+	// 为每个存储桶添加虚拟节点
+	for _, b := range buckets {
+		for i := 0; i < s.replicas; i++ {
+			virtualKey := fmt.Sprintf("%s-%d", b.Config.Name, i)
+			hash := s.hash(virtualKey)
+			s.ring[hash] = b
+			s.nodes = append(s.nodes, hash)
+		}
+	}
+
+	// 排序节点
+	sort.Slice(s.nodes, func(i, j int) bool {
+		return s.nodes[i] < s.nodes[j]
+	})
+}
+
+// hash 计算哈希值
+func (s *ConsistentHashStrategy) hash(key string) uint32 {
+	h := md5.Sum([]byte(key))
+	return binary.BigEndian.Uint32(h[:4])
+}
+
+// Name 返回策略名称
+func (s *ConsistentHashStrategy) Name() string {
+	return "consistent-hash"
+}
diff --git a/internal/bucket/manager.go b/internal/bucket/manager.go
new file mode 100644
index 0000000..c40cff0
--- /dev/null
+++ b/internal/bucket/manager.go
@@ -0,0 +1,310 @@
+package bucket
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/DullJZ/s3-balance/internal/config"
+	"github.com/aws/aws-sdk-go-v2/aws"
+	awsconfig "github.com/aws/aws-sdk-go-v2/config"
+	"github.com/aws/aws-sdk-go-v2/credentials"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+)
+
+// BucketInfo 存储桶信息
+type BucketInfo struct {
+	Config      config.BucketConfig
+	Client      *s3.Client
+	UsedSize    int64     // 已使用容量（字节）
+	Available   bool      // 是否可用
+	LastChecked time.Time // 最后检查时间
+	mu          sync.RWMutex
+}
+
+// Manager 存储桶管理器
+type Manager struct {
+	buckets  map[string]*BucketInfo
+	mu       sync.RWMutex
+	config   *config.Config
+	stopChan chan struct{}
+}
+
+// NewManager 创建新的存储桶管理器
+func NewManager(cfg *config.Config) (*Manager, error) {
+	m := &Manager{
+		buckets:  make(map[string]*BucketInfo),
+		config:   cfg,
+		stopChan: make(chan struct{}),
+	}
+
+	// 初始化所有存储桶客户端
+	for _, bucketCfg := range cfg.Buckets {
+		if !bucketCfg.Enabled {
+			continue
+		}
+
+		client, err := createS3Client(bucketCfg)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create S3 client for bucket %s: %w", bucketCfg.Name, err)
+		}
+
+		info := &BucketInfo{
+			Config:      bucketCfg,
+			Client:      client,
+			Available:   true,
+			LastChecked: time.Now(),
+		}
+
+		m.buckets[bucketCfg.Name] = info
+	}
+
+	return m, nil
+}
+
+// createS3Client 创建S3客户端
+func createS3Client(bucketCfg config.BucketConfig) (*s3.Client, error) {
+	// 创建自定义端点解析器
+	customResolver := aws.EndpointResolverWithOptionsFunc(func(service, region string, options ...interface{}) (aws.Endpoint, error) {
+		if bucketCfg.Endpoint != "" {
+			return aws.Endpoint{
+				URL:               bucketCfg.Endpoint,
+				SigningRegion:     bucketCfg.Region,
+				HostnameImmutable: true,
+			}, nil
+		}
+		// 返回错误以使用默认解析器
+		return aws.Endpoint{}, &aws.EndpointNotFoundError{}
+	})
+
+	// 配置AWS SDK
+	cfg, err := awsconfig.LoadDefaultConfig(context.TODO(),
+		awsconfig.WithRegion(bucketCfg.Region),
+		awsconfig.WithEndpointResolverWithOptions(customResolver),
+		awsconfig.WithCredentialsProvider(
+			credentials.NewStaticCredentialsProvider(
+				bucketCfg.AccessKeyID,
+				bucketCfg.SecretAccessKey,
+				"",
+			),
+		),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	// 创建S3客户端
+	client := s3.NewFromConfig(cfg, func(o *s3.Options) {
+		o.UsePathStyle = bucketCfg.PathStyle
+	})
+
+	return client, nil
+}
+
+// Start 启动管理器（健康检查和统计更新）
+func (m *Manager) Start(ctx context.Context) {
+	// 启动健康检查
+	go m.healthCheckLoop(ctx)
+	
+	// 启动统计更新
+	go m.statsUpdateLoop(ctx)
+}
+
+// Stop 停止管理器
+func (m *Manager) Stop() {
+	close(m.stopChan)
+}
+
+// healthCheckLoop 健康检查循环
+func (m *Manager) healthCheckLoop(ctx context.Context) {
+	ticker := time.NewTicker(m.config.Balancer.HealthCheckPeriod)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-m.stopChan:
+			return
+		case <-ticker.C:
+			m.checkAllBuckets(ctx)
+		}
+	}
+}
+
+// statsUpdateLoop 统计更新循环
+func (m *Manager) statsUpdateLoop(ctx context.Context) {
+	ticker := time.NewTicker(m.config.Balancer.UpdateStatsPeriod)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-m.stopChan:
+			return
+		case <-ticker.C:
+			m.updateAllStats(ctx)
+		}
+	}
+}
+
+// checkAllBuckets 检查所有存储桶的健康状态
+func (m *Manager) checkAllBuckets(ctx context.Context) {
+	m.mu.RLock()
+	buckets := make([]*BucketInfo, 0, len(m.buckets))
+	for _, b := range m.buckets {
+		buckets = append(buckets, b)
+	}
+	m.mu.RUnlock()
+
+	var wg sync.WaitGroup
+	for _, bucket := range buckets {
+		wg.Add(1)
+		go func(b *BucketInfo) {
+			defer wg.Done()
+			m.checkBucket(ctx, b)
+		}(bucket)
+	}
+	wg.Wait()
+}
+
+// checkBucket 检查单个存储桶
+func (m *Manager) checkBucket(ctx context.Context, bucket *BucketInfo) {
+	ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
+	defer cancel()
+
+	// 尝试列出存储桶（用于健康检查）
+	_, err := bucket.Client.ListObjectsV2(ctx, &s3.ListObjectsV2Input{
+		Bucket:  aws.String(bucket.Config.Name),
+		MaxKeys: aws.Int32(1),
+	})
+
+	bucket.mu.Lock()
+	bucket.Available = err == nil
+	bucket.LastChecked = time.Now()
+	bucket.mu.Unlock()
+}
+
+// updateAllStats 更新所有存储桶的统计信息
+func (m *Manager) updateAllStats(ctx context.Context) {
+	m.mu.RLock()
+	buckets := make([]*BucketInfo, 0, len(m.buckets))
+	for _, b := range m.buckets {
+		buckets = append(buckets, b)
+	}
+	m.mu.RUnlock()
+
+	var wg sync.WaitGroup
+	for _, bucket := range buckets {
+		wg.Add(1)
+		go func(b *BucketInfo) {
+			defer wg.Done()
+			m.updateBucketStats(ctx, b)
+		}(bucket)
+	}
+	wg.Wait()
+}
+
+// updateBucketStats 更新单个存储桶的统计信息
+func (m *Manager) updateBucketStats(ctx context.Context, bucket *BucketInfo) {
+	ctx, cancel := context.WithTimeout(ctx, 30*time.Second)
+	defer cancel()
+
+	var totalSize int64
+	var continuationToken *string
+
+	for {
+		output, err := bucket.Client.ListObjectsV2(ctx, &s3.ListObjectsV2Input{
+			Bucket:            aws.String(bucket.Config.Name),
+			ContinuationToken: continuationToken,
+		})
+		if err != nil {
+			break
+		}
+
+		for _, obj := range output.Contents {
+			if obj.Size != nil {
+				totalSize += *obj.Size
+			}
+		}
+
+		if output.IsTruncated == nil || !*output.IsTruncated {
+			break
+		}
+		continuationToken = output.NextContinuationToken
+	}
+
+	bucket.mu.Lock()
+	bucket.UsedSize = totalSize
+	bucket.mu.Unlock()
+}
+
+// GetBucket 获取指定名称的存储桶
+func (m *Manager) GetBucket(name string) (*BucketInfo, bool) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	bucket, ok := m.buckets[name]
+	return bucket, ok
+}
+
+// GetAllBuckets 获取所有存储桶
+func (m *Manager) GetAllBuckets() []*BucketInfo {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	
+	buckets := make([]*BucketInfo, 0, len(m.buckets))
+	for _, b := range m.buckets {
+		buckets = append(buckets, b)
+	}
+	return buckets
+}
+
+// GetAvailableBuckets 获取所有可用的存储桶
+func (m *Manager) GetAvailableBuckets() []*BucketInfo {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	
+	var available []*BucketInfo
+	for _, b := range m.buckets {
+		b.mu.RLock()
+		if b.Available && (b.Config.MaxSizeBytes == 0 || b.UsedSize < b.Config.MaxSizeBytes) {
+			available = append(available, b)
+		}
+		b.mu.RUnlock()
+	}
+	return available
+}
+
+// GetAvailableSpace 获取存储桶的可用空间
+func (b *BucketInfo) GetAvailableSpace() int64 {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	
+	if b.Config.MaxSizeBytes == 0 {
+		return 1 << 62 // 返回一个很大的数表示无限制
+	}
+	return b.Config.MaxSizeBytes - b.UsedSize
+}
+
+// IsAvailable 检查存储桶是否可用
+func (b *BucketInfo) IsAvailable() bool {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return b.Available
+}
+
+// GetUsedSize 获取已使用容量
+func (b *BucketInfo) GetUsedSize() int64 {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return b.UsedSize
+}
+
+// UpdateUsedSize 更新已使用容量
+func (b *BucketInfo) UpdateUsedSize(delta int64) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	b.UsedSize += delta
+}
diff --git a/internal/config/config.go b/internal/config/config.go
new file mode 100644
index 0000000..2fc76a3
--- /dev/null
+++ b/internal/config/config.go
@@ -0,0 +1,212 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"gopkg.in/yaml.v3"
+)
+
+// Config 全局配置结构
+type Config struct {
+	Server   ServerConfig   `yaml:"server"`
+	Database DatabaseConfig `yaml:"database"`
+	Buckets  []BucketConfig `yaml:"buckets"`
+	Balancer BalancerConfig `yaml:"balancer"`
+	Metrics  MetricsConfig  `yaml:"metrics"`
+	S3API    S3APIConfig    `yaml:"s3api"`
+}
+
+// ServerConfig 服务器配置
+type ServerConfig struct {
+	Host         string        `yaml:"host"`
+	Port         int           `yaml:"port"`
+	ReadTimeout  time.Duration `yaml:"read_timeout"`
+	WriteTimeout time.Duration `yaml:"write_timeout"`
+	IdleTimeout  time.Duration `yaml:"idle_timeout"`
+}
+
+// BucketConfig S3存储桶配置
+type BucketConfig struct {
+	Name            string  `yaml:"name"`              // 桶名称
+	Endpoint        string  `yaml:"endpoint"`          // S3端点
+	Region          string  `yaml:"region"`            // 区域
+	AccessKeyID     string  `yaml:"access_key_id"`     // 访问密钥ID
+	SecretAccessKey string  `yaml:"secret_access_key"` // 访问密钥
+	MaxSize         string  `yaml:"max_size"`          // 最大容量 (例如: "10GB")
+	MaxSizeBytes    int64   `yaml:"-"`                 // 内部使用，字节为单位
+	Weight          int     `yaml:"weight"`            // 权重 (用于负载均衡)
+	Enabled         bool    `yaml:"enabled"`           // 是否启用
+	UseSSL          bool    `yaml:"use_ssl"`           // 是否使用SSL
+	PathStyle       bool    `yaml:"path_style"`        // 是否使用路径风格访问
+}
+
+// BalancerConfig 负载均衡配置
+type BalancerConfig struct {
+	Strategy          string        `yaml:"strategy"`           // 负载均衡策略: "round-robin", "least-space", "weighted", "consistent-hash"
+	HealthCheckPeriod time.Duration `yaml:"health_check_period"` // 健康检查周期
+	UpdateStatsPeriod time.Duration `yaml:"update_stats_period"` // 统计更新周期
+	RetryAttempts     int           `yaml:"retry_attempts"`      // 重试次数
+	RetryDelay        time.Duration `yaml:"retry_delay"`         // 重试延迟
+}
+
+// MetricsConfig 监控指标配置
+type MetricsConfig struct {
+	Enabled bool   `yaml:"enabled"`
+	Path    string `yaml:"path"`
+	Port    int    `yaml:"port"`
+}
+
+// S3APIConfig S3兼容API配置
+type S3APIConfig struct {
+	AccessKey      string `yaml:"access_key"`       // S3访问密钥ID
+	SecretKey      string `yaml:"secret_key"`       // S3秘密访问密钥
+	VirtualHost    bool   `yaml:"virtual_host"`     // 是否使用虚拟主机模式
+	ProxyMode      bool   `yaml:"proxy_mode"`       // 是否使用代理模式（而非重定向）
+	AuthRequired   bool   `yaml:"auth_required"`    // 是否需要认证
+}
+
+// DatabaseConfig 数据库配置
+type DatabaseConfig struct {
+	Type            string `yaml:"type"`             // 数据库类型: sqlite, mysql, postgres
+	DSN             string `yaml:"dsn"`              // 数据源名称
+	MaxOpenConns    int    `yaml:"max_open_conns"`   // 最大打开连接数
+	MaxIdleConns    int    `yaml:"max_idle_conns"`   // 最大空闲连接数
+	ConnMaxLifetime int    `yaml:"conn_max_lifetime"` // 连接最大生命周期（秒）
+	LogLevel        string `yaml:"log_level"`        // 日志级别: silent, error, warn, info
+	AutoMigrate     bool   `yaml:"auto_migrate"`     // 是否自动迁移
+}
+
+// Load 从文件加载配置
+func Load(configPath string) (*Config, error) {
+	file, err := os.Open(configPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open config file: %w", err)
+	}
+	defer file.Close()
+
+	var config Config
+	decoder := yaml.NewDecoder(file)
+	if err := decoder.Decode(&config); err != nil {
+		return nil, fmt.Errorf("failed to decode config: %w", err)
+	}
+
+	// 解析容量大小
+	for i := range config.Buckets {
+		if err := config.Buckets[i].ParseMaxSize(); err != nil {
+			return nil, fmt.Errorf("failed to parse max size for bucket %s: %w", 
+				config.Buckets[i].Name, err)
+		}
+	}
+
+	// 设置默认值
+	config.SetDefaults()
+
+	return &config, nil
+}
+
+// SetDefaults 设置默认配置值
+func (c *Config) SetDefaults() {
+	if c.Server.Host == "" {
+		c.Server.Host = "0.0.0.0"
+	}
+	if c.Server.Port == 0 {
+		c.Server.Port = 8080
+	}
+	if c.Server.ReadTimeout == 0 {
+		c.Server.ReadTimeout = 30 * time.Second
+	}
+	if c.Server.WriteTimeout == 0 {
+		c.Server.WriteTimeout = 30 * time.Second
+	}
+	if c.Server.IdleTimeout == 0 {
+		c.Server.IdleTimeout = 60 * time.Second
+	}
+
+	if c.Balancer.Strategy == "" {
+		c.Balancer.Strategy = "least-space"
+	}
+	if c.Balancer.HealthCheckPeriod == 0 {
+		c.Balancer.HealthCheckPeriod = 30 * time.Second
+	}
+	if c.Balancer.UpdateStatsPeriod == 0 {
+		c.Balancer.UpdateStatsPeriod = 60 * time.Second
+	}
+	if c.Balancer.RetryAttempts == 0 {
+		c.Balancer.RetryAttempts = 3
+	}
+	if c.Balancer.RetryDelay == 0 {
+		c.Balancer.RetryDelay = time.Second
+	}
+
+	if c.Metrics.Path == "" {
+		c.Metrics.Path = "/metrics"
+	}
+	if c.Metrics.Port == 0 {
+		c.Metrics.Port = 9090
+	}
+
+	// 数据库默认值
+	if c.Database.Type == "" {
+		c.Database.Type = "sqlite"
+	}
+	if c.Database.Type == "sqlite" && c.Database.DSN == "" {
+		c.Database.DSN = "data/s3-balance.db"
+	}
+	if c.Database.MaxOpenConns == 0 {
+		c.Database.MaxOpenConns = 25
+	}
+	if c.Database.MaxIdleConns == 0 {
+		c.Database.MaxIdleConns = 5
+	}
+	if c.Database.ConnMaxLifetime == 0 {
+		c.Database.ConnMaxLifetime = 300
+	}
+	if c.Database.LogLevel == "" {
+		c.Database.LogLevel = "warn"
+	}
+
+	// S3 API默认值
+	if c.S3API.AccessKey == "" {
+		c.S3API.AccessKey = "AKIAIOSFODNN7EXAMPLE"
+	}
+	if c.S3API.SecretKey == "" {
+		c.S3API.SecretKey = "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"
+	}
+	// 默认使用预签名模式（非代理模式）
+	c.S3API.ProxyMode = false
+	c.S3API.AuthRequired = false
+}
+
+// ParseMaxSize 解析最大容量字符串为字节
+func (bc *BucketConfig) ParseMaxSize() error {
+	if bc.MaxSize == "" {
+		bc.MaxSizeBytes = 0 // 无限制
+		return nil
+	}
+
+	var size int64
+	var unit string
+	_, err := fmt.Sscanf(bc.MaxSize, "%d%s", &size, &unit)
+	if err != nil {
+		return fmt.Errorf("invalid size format: %s", bc.MaxSize)
+	}
+
+	switch unit {
+	case "B", "b":
+		bc.MaxSizeBytes = size
+	case "KB", "kb", "K", "k":
+		bc.MaxSizeBytes = size * 1024
+	case "MB", "mb", "M", "m":
+		bc.MaxSizeBytes = size * 1024 * 1024
+	case "GB", "gb", "G", "g":
+		bc.MaxSizeBytes = size * 1024 * 1024 * 1024
+	case "TB", "tb", "T", "t":
+		bc.MaxSizeBytes = size * 1024 * 1024 * 1024 * 1024
+	default:
+		return fmt.Errorf("unsupported unit: %s", unit)
+	}
+
+	return nil
+}
diff --git a/internal/database/database.go b/internal/database/database.go
new file mode 100644
index 0000000..5436e6f
--- /dev/null
+++ b/internal/database/database.go
@@ -0,0 +1,230 @@
+package database
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/DullJZ/s3-balance/internal/config"
+	"github.com/DullJZ/s3-balance/internal/storage"
+	"gorm.io/driver/mysql"
+	"gorm.io/driver/postgres"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+// DB 全局数据库连接
+var DB *gorm.DB
+
+// Initialize 初始化数据库连接
+func Initialize(cfg *config.DatabaseConfig) error {
+	var err error
+	
+	// 设置日志级别
+	logLevel := getLogLevel(cfg.LogLevel)
+	
+	// GORM配置
+	gormConfig := &gorm.Config{
+		Logger: logger.Default.LogMode(logLevel),
+		NowFunc: func() time.Time {
+			return time.Now().Local()
+		},
+		QueryFields: true,
+	}
+	
+	// 根据数据库类型创建连接
+	switch cfg.Type {
+	case "sqlite":
+		DB, err = connectSQLite(cfg.DSN, gormConfig)
+	case "mysql":
+		DB, err = connectMySQL(cfg.DSN, gormConfig)
+	case "postgres", "postgresql":
+		DB, err = connectPostgreSQL(cfg.DSN, gormConfig)
+	default:
+		return fmt.Errorf("unsupported database type: %s", cfg.Type)
+	}
+	
+	if err != nil {
+		return fmt.Errorf("failed to connect to database: %w", err)
+	}
+	
+	// 获取底层SQL数据库连接
+	sqlDB, err := DB.DB()
+	if err != nil {
+		return fmt.Errorf("failed to get sql.DB: %w", err)
+	}
+	
+	// 设置连接池参数
+	sqlDB.SetMaxOpenConns(cfg.MaxOpenConns)
+	sqlDB.SetMaxIdleConns(cfg.MaxIdleConns)
+	sqlDB.SetConnMaxLifetime(time.Duration(cfg.ConnMaxLifetime) * time.Second)
+	
+	// 测试连接
+	if err := sqlDB.Ping(); err != nil {
+		return fmt.Errorf("failed to ping database: %w", err)
+	}
+	
+	// 自动迁移
+	if cfg.AutoMigrate {
+		if err := AutoMigrate(); err != nil {
+			return fmt.Errorf("failed to auto migrate: %w", err)
+		}
+	}
+	
+	log.Printf("Successfully connected to %s database", cfg.Type)
+	return nil
+}
+
+// connectSQLite 连接SQLite数据库
+func connectSQLite(dsn string, gormConfig *gorm.Config) (*gorm.DB, error) {
+	// 创建数据目录（如果不存在）
+	dir := filepath.Dir(dsn)
+	if dir != "" && dir != "." {
+		if err := os.MkdirAll(dir, 0755); err != nil {
+			return nil, fmt.Errorf("failed to create database directory: %w", err)
+		}
+	}
+	
+	// 添加SQLite特定参数
+	if dsn != ":memory:" {
+		dsn = fmt.Sprintf("%s?_journal_mode=WAL&_timeout=5000&_synchronous=NORMAL&_cache_size=10000", dsn)
+	}
+	
+	return gorm.Open(sqlite.Open(dsn), gormConfig)
+}
+
+// connectMySQL 连接MySQL数据库
+func connectMySQL(dsn string, gormConfig *gorm.Config) (*gorm.DB, error) {
+	// MySQL DSN示例: user:password@tcp(localhost:3306)/dbname?charset=utf8mb4&parseTime=True&loc=Local
+	
+	// 如果DSN中没有指定字符集，添加默认字符集
+	if dsn != "" {
+		dsn = ensureMySQLParams(dsn)
+	}
+	
+	return gorm.Open(mysql.Open(dsn), gormConfig)
+}
+
+// connectPostgreSQL 连接PostgreSQL数据库
+func connectPostgreSQL(dsn string, gormConfig *gorm.Config) (*gorm.DB, error) {
+	// PostgreSQL DSN示例: host=localhost user=user password=password dbname=mydb port=5432 sslmode=disable TimeZone=Asia/Shanghai
+	
+	return gorm.Open(postgres.Open(dsn), gormConfig)
+}
+
+// ensureMySQLParams 确保MySQL DSN包含必要的参数
+func ensureMySQLParams(dsn string) string {
+	params := map[string]string{
+		"charset":   "utf8mb4",
+		"parseTime": "True",
+		"loc":       "Local",
+	}
+	
+	separator := "?"
+	if len(dsn) > 0 && dsn[len(dsn)-1] == '?' {
+		separator = ""
+	} else if contains(dsn, "?") {
+		separator = "&"
+	}
+	
+	for key, value := range params {
+		if !contains(dsn, key+"=") {
+			dsn = fmt.Sprintf("%s%s%s=%s", dsn, separator, key, value)
+			separator = "&"
+		}
+	}
+	
+	return dsn
+}
+
+// contains 检查字符串是否包含子串
+func contains(s, substr string) bool {
+	return len(s) >= len(substr) && (s == substr || len(s) > 0 && containsHelper(s, substr))
+}
+
+func containsHelper(s, substr string) bool {
+	for i := 0; i <= len(s)-len(substr); i++ {
+		if s[i:i+len(substr)] == substr {
+			return true
+		}
+	}
+	return false
+}
+
+// getLogLevel 获取GORM日志级别
+func getLogLevel(level string) logger.LogLevel {
+	switch level {
+	case "silent":
+		return logger.Silent
+	case "error":
+		return logger.Error
+	case "warn", "warning":
+		return logger.Warn
+	case "info":
+		return logger.Info
+	default:
+		return logger.Warn
+	}
+}
+
+// AutoMigrate 自动迁移数据库表
+func AutoMigrate() error {
+	models := []interface{}{
+		&storage.Object{},
+		&storage.BucketStats{},
+		&storage.UploadSession{},
+		&storage.AccessLog{},
+	}
+	
+	for _, model := range models {
+		if err := DB.AutoMigrate(model); err != nil {
+			return fmt.Errorf("failed to migrate %T: %w", model, err)
+		}
+	}
+	
+	log.Println("Database migration completed successfully")
+	return nil
+}
+
+// Close 关闭数据库连接
+func Close() error {
+	if DB != nil {
+		sqlDB, err := DB.DB()
+		if err != nil {
+			return err
+		}
+		return sqlDB.Close()
+	}
+	return nil
+}
+
+// HealthCheck 健康检查
+func HealthCheck() error {
+	if DB == nil {
+		return fmt.Errorf("database not initialized")
+	}
+	
+	sqlDB, err := DB.DB()
+	if err != nil {
+		return err
+	}
+	
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	
+	return sqlDB.PingContext(ctx)
+}
+
+// Transaction 执行事务
+func Transaction(fn func(*gorm.DB) error) error {
+	return DB.Transaction(fn)
+}
+
+// GetDB 获取数据库连接
+func GetDB() *gorm.DB {
+	return DB
+}
diff --git a/internal/storage/models.go b/internal/storage/models.go
new file mode 100644
index 0000000..cf89c68
--- /dev/null
+++ b/internal/storage/models.go
@@ -0,0 +1,163 @@
+package storage
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"time"
+
+	"gorm.io/gorm"
+)
+
+// Object 对象信息模型
+type Object struct {
+	ID         uint           `gorm:"primaryKey" json:"id"`
+	Key        string         `gorm:"uniqueIndex;size:512;not null" json:"key"`
+	BucketName string         `gorm:"index;size:255;not null" json:"bucket_name"`
+	Size       int64          `gorm:"not null;default:0" json:"size"`
+	Metadata   JSON           `gorm:"type:json" json:"metadata,omitempty"`
+	ContentType string        `gorm:"size:128" json:"content_type,omitempty"`
+	ETag       string         `gorm:"size:128" json:"etag,omitempty"`
+	CreatedAt  time.Time      `json:"created_at"`
+	UpdatedAt  time.Time      `json:"updated_at"`
+	DeletedAt  gorm.DeletedAt `gorm:"index" json:"-"`
+}
+
+// TableName 指定表名
+func (Object) TableName() string {
+	return "objects"
+}
+
+// BucketStats 存储桶统计信息模型
+type BucketStats struct {
+	ID            uint      `gorm:"primaryKey" json:"id"`
+	BucketName    string    `gorm:"uniqueIndex;size:255;not null" json:"bucket_name"`
+	ObjectCount   int64     `gorm:"not null;default:0" json:"object_count"`
+	TotalSize     int64     `gorm:"not null;default:0" json:"total_size"`
+	LastCheckedAt time.Time `json:"last_checked_at"`
+	CreatedAt     time.Time `json:"created_at"`
+	UpdatedAt     time.Time `json:"updated_at"`
+}
+
+// TableName 指定表名
+func (BucketStats) TableName() string {
+	return "bucket_stats"
+}
+
+// UploadSession 上传会话模型（用于跟踪分片上传）
+type UploadSession struct {
+	ID             uint           `gorm:"primaryKey" json:"id"`
+	UploadID       string         `gorm:"uniqueIndex;size:255;not null" json:"upload_id"`
+	Key            string         `gorm:"index;size:512;not null" json:"key"`
+	BucketName     string         `gorm:"index;size:255;not null" json:"bucket_name"`
+	TotalParts     int            `gorm:"not null;default:0" json:"total_parts"`
+	CompletedParts int            `gorm:"not null;default:0" json:"completed_parts"`
+	Size           int64          `gorm:"not null;default:0" json:"size"`
+	Status         string         `gorm:"size:32;not null;default:'pending'" json:"status"` // pending, completed, aborted
+	ExpiresAt      time.Time      `gorm:"index" json:"expires_at"`
+	CreatedAt      time.Time      `json:"created_at"`
+	UpdatedAt      time.Time      `json:"updated_at"`
+	DeletedAt      gorm.DeletedAt `gorm:"index" json:"-"`
+}
+
+// TableName 指定表名
+func (UploadSession) TableName() string {
+	return "upload_sessions"
+}
+
+// AccessLog 访问日志模型
+type AccessLog struct {
+	ID          uint      `gorm:"primaryKey" json:"id"`
+	Action      string    `gorm:"index;size:32;not null" json:"action"` // upload, download, delete
+	Key         string    `gorm:"index;size:512;not null" json:"key"`
+	BucketName  string    `gorm:"index;size:255" json:"bucket_name"`
+	Size        int64     `gorm:"default:0" json:"size"`
+	ClientIP    string    `gorm:"size:64" json:"client_ip"`
+	UserAgent   string    `gorm:"size:512" json:"user_agent"`
+	Success     bool      `gorm:"default:true" json:"success"`
+	ErrorMsg    string    `gorm:"type:text" json:"error_msg,omitempty"`
+	ResponseTime int64    `gorm:"default:0" json:"response_time"` // 响应时间（毫秒）
+	CreatedAt   time.Time `gorm:"index" json:"created_at"`
+}
+
+// TableName 指定表名
+func (AccessLog) TableName() string {
+	return "access_logs"
+}
+
+// JSON 自定义JSON类型，用于存储元数据
+type JSON map[string]interface{}
+
+// Value 实现driver.Valuer接口
+func (j JSON) Value() (driver.Value, error) {
+	if j == nil {
+		return nil, nil
+	}
+	return json.Marshal(j)
+}
+
+// Scan 实现sql.Scanner接口
+func (j *JSON) Scan(value interface{}) error {
+	if value == nil {
+		*j = make(map[string]interface{})
+		return nil
+	}
+	
+	var data []byte
+	switch v := value.(type) {
+	case []byte:
+		data = v
+	case string:
+		data = []byte(v)
+	default:
+		data = []byte("{}")
+	}
+	
+	return json.Unmarshal(data, j)
+}
+
+// BeforeCreate GORM钩子 - 创建前
+func (o *Object) BeforeCreate(tx *gorm.DB) error {
+	if o.Metadata == nil {
+		o.Metadata = make(JSON)
+	}
+	return nil
+}
+
+// BeforeCreate GORM钩子 - 创建前设置过期时间
+func (u *UploadSession) BeforeCreate(tx *gorm.DB) error {
+	if u.ExpiresAt.IsZero() {
+		u.ExpiresAt = time.Now().Add(24 * time.Hour) // 默认24小时过期
+	}
+	return nil
+}
+
+// IsExpired 检查上传会话是否过期
+func (u *UploadSession) IsExpired() bool {
+	return time.Now().After(u.ExpiresAt)
+}
+
+// ObjectFilter 对象查询过滤器
+type ObjectFilter struct {
+	Key        string
+	BucketName string
+	Prefix     string
+	MinSize    int64
+	MaxSize    int64
+	StartTime  time.Time
+	EndTime    time.Time
+	Limit      int
+	Offset     int
+}
+
+// AccessLogFilter 访问日志查询过滤器
+type AccessLogFilter struct {
+	Action     string
+	Key        string
+	BucketName string
+	ClientIP   string
+	Success    *bool
+	StartTime  time.Time
+	EndTime    time.Time
+	Limit      int
+	Offset     int
+}
diff --git a/internal/storage/service.go b/internal/storage/service.go
new file mode 100644
index 0000000..d6c2b22
--- /dev/null
+++ b/internal/storage/service.go
@@ -0,0 +1,350 @@
+package storage
+
+import (
+	"fmt"
+	"time"
+
+	"gorm.io/gorm"
+)
+
+// Service 存储服务（管理对象元数据）
+type Service struct {
+	db *gorm.DB
+}
+
+// NewService 创建新的存储服务
+func NewService(db *gorm.DB) *Service {
+	return &Service{
+		db: db,
+	}
+}
+
+// RecordObject 记录对象信息
+func (s *Service) RecordObject(key, bucketName string, size int64, metadata map[string]string) error {
+	obj := &Object{
+		Key:        key,
+		BucketName: bucketName,
+		Size:       size,
+	}
+	
+	if len(metadata) > 0 {
+		obj.Metadata = make(JSON)
+		for k, v := range metadata {
+			obj.Metadata[k] = v
+		}
+	} else {
+		obj.Metadata = make(JSON)
+	}
+	
+	// 使用 Upsert（更新或插入）
+	result := s.db.Where("key = ?", key).FirstOrCreate(&obj)
+	if result.Error != nil {
+		return fmt.Errorf("failed to record object: %w", result.Error)
+	}
+	
+	if result.RowsAffected == 0 {
+		// 对象已存在，更新它
+		updates := map[string]interface{}{
+			"bucket_name": bucketName,
+			"size":        size,
+			"metadata":    obj.Metadata,
+			"updated_at":  time.Now(),
+		}
+		if err := s.db.Model(&Object{}).Where("key = ?", key).Updates(updates).Error; err != nil {
+			return fmt.Errorf("failed to update object: %w", err)
+		}
+	}
+	
+	// 更新存储桶统计
+	s.updateBucketStats(bucketName)
+	
+	return nil
+}
+
+// FindObjectBucket 查找对象所在的存储桶
+func (s *Service) FindObjectBucket(key string) (string, error) {
+	var obj Object
+	if err := s.db.Where("key = ?", key).First(&obj).Error; err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return "", fmt.Errorf("object not found: %s", key)
+		}
+		return "", fmt.Errorf("failed to find object: %w", err)
+	}
+	return obj.BucketName, nil
+}
+
+// GetObjectInfo 获取对象信息
+func (s *Service) GetObjectInfo(key string) (*Object, error) {
+	var obj Object
+	if err := s.db.Where("key = ?", key).First(&obj).Error; err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return nil, fmt.Errorf("object not found: %s", key)
+		}
+		return nil, fmt.Errorf("failed to get object info: %w", err)
+	}
+	return &obj, nil
+}
+
+// DeleteObject 删除对象记录（软删除）
+func (s *Service) DeleteObject(key string) error {
+	var obj Object
+	if err := s.db.Where("key = ?", key).First(&obj).Error; err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return fmt.Errorf("object not found: %s", key)
+		}
+		return fmt.Errorf("failed to find object: %w", err)
+	}
+	
+	bucketName := obj.BucketName
+	
+	// 软删除
+	if err := s.db.Delete(&obj).Error; err != nil {
+		return fmt.Errorf("failed to delete object: %w", err)
+	}
+	
+	// 更新存储桶统计
+	s.updateBucketStats(bucketName)
+	
+	return nil
+}
+
+// ListObjects 列出对象（支持S3兼容的参数）
+func (s *Service) ListObjects(bucketName, prefix, marker string, maxKeys int) ([]*Object, error) {
+	var objects []*Object
+	query := s.db.Model(&Object{})
+	
+	// 按bucket过滤
+	if bucketName != "" {
+		query = query.Where("bucket_name = ?", bucketName)
+	}
+	
+	// 前缀过滤
+	if prefix != "" {
+		query = query.Where("key LIKE ?", prefix+"%")
+	}
+	
+	// Marker分页
+	if marker != "" {
+		query = query.Where("key > ?", marker)
+	}
+	
+	// 限制返回数量
+	if maxKeys > 0 {
+		query = query.Limit(maxKeys)
+	}
+	
+	// 按key字母顺序排序（S3标准）
+	if err := query.Order("key ASC").Find(&objects).Error; err != nil {
+		return nil, fmt.Errorf("failed to list objects: %w", err)
+	}
+	
+	return objects, nil
+}
+
+// GetBucketObjects 获取特定存储桶的所有对象
+func (s *Service) GetBucketObjects(bucketName string) ([]*Object, error) {
+	var objects []*Object
+	if err := s.db.Where("bucket_name = ?", bucketName).Find(&objects).Error; err != nil {
+		return nil, fmt.Errorf("failed to get bucket objects: %w", err)
+	}
+	return objects, nil
+}
+
+// GetTotalSize 获取所有对象的总大小
+func (s *Service) GetTotalSize() (int64, error) {
+	var total int64
+	if err := s.db.Model(&Object{}).Select("COALESCE(SUM(size), 0)").Scan(&total).Error; err != nil {
+		return 0, fmt.Errorf("failed to get total size: %w", err)
+	}
+	return total, nil
+}
+
+// GetBucketSize 获取特定存储桶的总大小
+func (s *Service) GetBucketSize(bucketName string) (int64, error) {
+	var total int64
+	if err := s.db.Model(&Object{}).
+		Where("bucket_name = ?", bucketName).
+		Select("COALESCE(SUM(size), 0)").
+		Scan(&total).Error; err != nil {
+		return 0, fmt.Errorf("failed to get bucket size: %w", err)
+	}
+	return total, nil
+}
+
+// GetObjectCount 获取对象总数
+func (s *Service) GetObjectCount() (int64, error) {
+	var count int64
+	if err := s.db.Model(&Object{}).Count(&count).Error; err != nil {
+		return 0, fmt.Errorf("failed to get object count: %w", err)
+	}
+	return count, nil
+}
+
+// GetBucketObjectCount 获取特定存储桶的对象数
+func (s *Service) GetBucketObjectCount(bucketName string) (int64, error) {
+	var count int64
+	if err := s.db.Model(&Object{}).
+		Where("bucket_name = ?", bucketName).
+		Count(&count).Error; err != nil {
+		return 0, fmt.Errorf("failed to get bucket object count: %w", err)
+	}
+	return count, nil
+}
+
+// updateBucketStats 更新存储桶统计信息
+func (s *Service) updateBucketStats(bucketName string) error {
+	var stats BucketStats
+	
+	// 获取或创建统计记录
+	result := s.db.Where("bucket_name = ?", bucketName).FirstOrCreate(&stats, BucketStats{
+		BucketName: bucketName,
+	})
+	if result.Error != nil {
+		return fmt.Errorf("failed to get bucket stats: %w", result.Error)
+	}
+	
+	// 计算新的统计数据
+	var count int64
+	var totalSize int64
+	
+	s.db.Model(&Object{}).
+		Where("bucket_name = ?", bucketName).
+		Count(&count)
+	
+	s.db.Model(&Object{}).
+		Where("bucket_name = ?", bucketName).
+		Select("COALESCE(SUM(size), 0)").
+		Scan(&totalSize)
+	
+	// 更新统计数据
+	updates := map[string]interface{}{
+		"object_count":    count,
+		"total_size":      totalSize,
+		"last_checked_at": time.Now(),
+	}
+	
+	if err := s.db.Model(&stats).Updates(updates).Error; err != nil {
+		return fmt.Errorf("failed to update bucket stats: %w", err)
+	}
+	
+	return nil
+}
+
+// RecordUploadSession 记录上传会话
+func (s *Service) RecordUploadSession(uploadID, key, bucketName string, totalParts int, size int64) error {
+	session := &UploadSession{
+		UploadID:   uploadID,
+		Key:        key,
+		BucketName: bucketName,
+		TotalParts: totalParts,
+		Size:       size,
+		Status:     "pending",
+	}
+	
+	if err := s.db.Create(session).Error; err != nil {
+		return fmt.Errorf("failed to record upload session: %w", err)
+	}
+	
+	return nil
+}
+
+// GetUploadSession 获取上传会话
+func (s *Service) GetUploadSession(uploadID string) (*UploadSession, error) {
+	var session UploadSession
+	if err := s.db.Where("upload_id = ?", uploadID).First(&session).Error; err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return nil, fmt.Errorf("upload session not found: %s", uploadID)
+		}
+		return nil, fmt.Errorf("failed to get upload session: %w", err)
+	}
+	return &session, nil
+}
+
+// UpdateUploadSession 更新上传会话
+func (s *Service) UpdateUploadSession(uploadID string, completedParts int, status string) error {
+	updates := map[string]interface{}{
+		"completed_parts": completedParts,
+		"status":          status,
+		"updated_at":      time.Now(),
+	}
+	
+	if err := s.db.Model(&UploadSession{}).
+		Where("upload_id = ?", uploadID).
+		Updates(updates).Error; err != nil {
+		return fmt.Errorf("failed to update upload session: %w", err)
+	}
+	
+	return nil
+}
+
+// CleanExpiredSessions 清理过期的上传会话
+func (s *Service) CleanExpiredSessions() error {
+	if err := s.db.Where("expires_at < ? AND status = ?", time.Now(), "pending").
+		Delete(&UploadSession{}).Error; err != nil {
+		return fmt.Errorf("failed to clean expired sessions: %w", err)
+	}
+	return nil
+}
+
+// RecordAccessLog 记录访问日志
+func (s *Service) RecordAccessLog(action, key, bucketName, clientIP, userAgent string, size int64, success bool, errorMsg string, responseTime int64) error {
+	log := &AccessLog{
+		Action:       action,
+		Key:          key,
+		BucketName:   bucketName,
+		ClientIP:     clientIP,
+		UserAgent:    userAgent,
+		Size:         size,
+		Success:      success,
+		ErrorMsg:     errorMsg,
+		ResponseTime: responseTime,
+	}
+	
+	if err := s.db.Create(log).Error; err != nil {
+		return fmt.Errorf("failed to record access log: %w", err)
+	}
+	
+	return nil
+}
+
+// GetAccessLogs 获取访问日志
+func (s *Service) GetAccessLogs(filter *AccessLogFilter) ([]*AccessLog, error) {
+	query := s.db.Model(&AccessLog{})
+	
+	if filter != nil {
+		if filter.Action != "" {
+			query = query.Where("action = ?", filter.Action)
+		}
+		if filter.Key != "" {
+			query = query.Where("key = ?", filter.Key)
+		}
+		if filter.BucketName != "" {
+			query = query.Where("bucket_name = ?", filter.BucketName)
+		}
+		if filter.ClientIP != "" {
+			query = query.Where("client_ip = ?", filter.ClientIP)
+		}
+		if filter.Success != nil {
+			query = query.Where("success = ?", *filter.Success)
+		}
+		if !filter.StartTime.IsZero() {
+			query = query.Where("created_at >= ?", filter.StartTime)
+		}
+		if !filter.EndTime.IsZero() {
+			query = query.Where("created_at <= ?", filter.EndTime)
+		}
+		if filter.Limit > 0 {
+			query = query.Limit(filter.Limit)
+		}
+		if filter.Offset > 0 {
+			query = query.Offset(filter.Offset)
+		}
+	}
+	
+	var logs []*AccessLog
+	if err := query.Order("created_at DESC").Find(&logs).Error; err != nil {
+		return nil, fmt.Errorf("failed to get access logs: %w", err)
+	}
+	
+	return logs, nil
+}
diff --git a/pkg/presigner/multipart.go b/pkg/presigner/multipart.go
new file mode 100644
index 0000000..e87e800
--- /dev/null
+++ b/pkg/presigner/multipart.go
@@ -0,0 +1,85 @@
+package presigner
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/DullJZ/s3-balance/internal/bucket"
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+	"github.com/aws/aws-sdk-go-v2/service/s3/types"
+)
+
+// CompletedPart 已完成的分片信息
+type CompletedPart struct {
+	PartNumber int32  `json:"part_number"`
+	ETag       string `json:"etag"`
+}
+
+// CompleteMultipartUpload 完成分片上传
+func CompleteMultipartUpload(ctx context.Context, bucket *bucket.BucketInfo, key, uploadID string, parts []CompletedPart) error {
+	// 转换为AWS SDK格式
+	var completedParts []types.CompletedPart
+	for _, part := range parts {
+		completedParts = append(completedParts, types.CompletedPart{
+			PartNumber: aws.Int32(part.PartNumber),
+			ETag:       aws.String(part.ETag),
+		})
+	}
+
+	// 完成分片上传
+	_, err := bucket.Client.CompleteMultipartUpload(ctx, &s3.CompleteMultipartUploadInput{
+		Bucket:   aws.String(bucket.Config.Name),
+		Key:      aws.String(key),
+		UploadId: aws.String(uploadID),
+		MultipartUpload: &types.CompletedMultipartUpload{
+			Parts: completedParts,
+		},
+	})
+	if err != nil {
+		return fmt.Errorf("failed to complete multipart upload: %w", err)
+	}
+
+	return nil
+}
+
+// AbortMultipartUpload 中止分片上传
+func AbortMultipartUpload(ctx context.Context, bucket *bucket.BucketInfo, key, uploadID string) error {
+	_, err := bucket.Client.AbortMultipartUpload(ctx, &s3.AbortMultipartUploadInput{
+		Bucket:   aws.String(bucket.Config.Name),
+		Key:      aws.String(key),
+		UploadId: aws.String(uploadID),
+	})
+	if err != nil {
+		return fmt.Errorf("failed to abort multipart upload: %w", err)
+	}
+
+	return nil
+}
+
+// ListParts 列出已上传的分片
+func ListParts(ctx context.Context, bucket *bucket.BucketInfo, key, uploadID string) ([]types.Part, error) {
+	var allParts []types.Part
+	var nextPartNumberMarker *string
+
+	for {
+		output, err := bucket.Client.ListParts(ctx, &s3.ListPartsInput{
+			Bucket:           aws.String(bucket.Config.Name),
+			Key:              aws.String(key),
+			UploadId:         aws.String(uploadID),
+			PartNumberMarker: nextPartNumberMarker,
+		})
+		if err != nil {
+			return nil, fmt.Errorf("failed to list parts: %w", err)
+		}
+
+		allParts = append(allParts, output.Parts...)
+
+		if output.IsTruncated == nil || !*output.IsTruncated {
+			break
+		}
+		nextPartNumberMarker = output.NextPartNumberMarker
+	}
+
+	return allParts, nil
+}
diff --git a/pkg/presigner/presigner.go b/pkg/presigner/presigner.go
new file mode 100644
index 0000000..0819f24
--- /dev/null
+++ b/pkg/presigner/presigner.go
@@ -0,0 +1,221 @@
+package presigner
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/DullJZ/s3-balance/internal/bucket"
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+)
+
+// Presigner 预签名URL生成器
+type Presigner struct {
+	uploadExpiry   time.Duration
+	downloadExpiry time.Duration
+}
+
+// NewPresigner 创建新的预签名URL生成器
+func NewPresigner(uploadExpiry, downloadExpiry time.Duration) *Presigner {
+	// 设置默认值
+	if uploadExpiry == 0 {
+		uploadExpiry = 15 * time.Minute
+	}
+	if downloadExpiry == 0 {
+		downloadExpiry = 60 * time.Minute
+	}
+
+	return &Presigner{
+		uploadExpiry:   uploadExpiry,
+		downloadExpiry: downloadExpiry,
+	}
+}
+
+// UploadURL 生成上传预签名URL
+type UploadURL struct {
+	URL        string            `json:"url"`
+	Method     string            `json:"method"`
+	Headers    map[string]string `json:"headers,omitempty"`
+	Expiry     time.Time        `json:"expiry"`
+	BucketName string           `json:"bucket_name"`
+	Key        string           `json:"key"`
+}
+
+// GenerateUploadURL 生成上传预签名URL
+func (p *Presigner) GenerateUploadURL(ctx context.Context, bucket *bucket.BucketInfo, key string, contentType string, metadata map[string]string) (*UploadURL, error) {
+	presignClient := s3.NewPresignClient(bucket.Client)
+
+	// 构建PutObject请求
+	putObjectInput := &s3.PutObjectInput{
+		Bucket: aws.String(bucket.Config.Name),
+		Key:    aws.String(key),
+	}
+
+	// 设置Content-Type
+	if contentType != "" {
+		putObjectInput.ContentType = aws.String(contentType)
+	}
+
+	// 设置元数据
+	if len(metadata) > 0 {
+		putObjectInput.Metadata = metadata
+	}
+
+	// 生成预签名URL
+	presignRequest, err := presignClient.PresignPutObject(ctx, putObjectInput, func(opts *s3.PresignOptions) {
+		opts.Expires = p.uploadExpiry
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate upload presigned URL: %w", err)
+	}
+
+	// 转换Headers为map[string]string
+	headers := make(map[string]string)
+	for k, v := range presignRequest.SignedHeader {
+		if len(v) > 0 {
+			headers[k] = v[0]
+		}
+	}
+	
+	return &UploadURL{
+		URL:        presignRequest.URL,
+		Method:     presignRequest.Method,
+		Headers:    headers,
+		Expiry:     time.Now().Add(p.uploadExpiry),
+		BucketName: bucket.Config.Name,
+		Key:        key,
+	}, nil
+}
+
+// DownloadURL 生成下载预签名URL
+type DownloadURL struct {
+	URL        string    `json:"url"`
+	Method     string    `json:"method"`
+	Expiry     time.Time `json:"expiry"`
+	BucketName string    `json:"bucket_name"`
+	Key        string    `json:"key"`
+}
+
+// GenerateDownloadURL 生成下载预签名URL
+func (p *Presigner) GenerateDownloadURL(ctx context.Context, bucket *bucket.BucketInfo, key string) (*DownloadURL, error) {
+	presignClient := s3.NewPresignClient(bucket.Client)
+
+	// 构建GetObject请求
+	getObjectInput := &s3.GetObjectInput{
+		Bucket: aws.String(bucket.Config.Name),
+		Key:    aws.String(key),
+	}
+
+	// 生成预签名URL
+	presignRequest, err := presignClient.PresignGetObject(ctx, getObjectInput, func(opts *s3.PresignOptions) {
+		opts.Expires = p.downloadExpiry
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate download presigned URL: %w", err)
+	}
+
+	return &DownloadURL{
+		URL:        presignRequest.URL,
+		Method:     presignRequest.Method,
+		Expiry:     time.Now().Add(p.downloadExpiry),
+		BucketName: bucket.Config.Name,
+		Key:        key,
+	}, nil
+}
+
+// DeleteURL 生成删除预签名URL
+type DeleteURL struct {
+	URL        string    `json:"url"`
+	Method     string    `json:"method"`
+	Expiry     time.Time `json:"expiry"`
+	BucketName string    `json:"bucket_name"`
+	Key        string    `json:"key"`
+}
+
+// GenerateDeleteURL 生成删除预签名URL
+func (p *Presigner) GenerateDeleteURL(ctx context.Context, bucket *bucket.BucketInfo, key string) (*DeleteURL, error) {
+	presignClient := s3.NewPresignClient(bucket.Client)
+
+	// 构建DeleteObject请求
+	deleteObjectInput := &s3.DeleteObjectInput{
+		Bucket: aws.String(bucket.Config.Name),
+		Key:    aws.String(key),
+	}
+
+	// 生成预签名URL
+	presignRequest, err := presignClient.PresignDeleteObject(ctx, deleteObjectInput, func(opts *s3.PresignOptions) {
+		opts.Expires = 5 * time.Minute // 删除操作的URL有效期较短
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate delete presigned URL: %w", err)
+	}
+
+	return &DeleteURL{
+		URL:        presignRequest.URL,
+		Method:     presignRequest.Method,
+		Expiry:     time.Now().Add(5 * time.Minute),
+		BucketName: bucket.Config.Name,
+		Key:        key,
+	}, nil
+}
+
+// MultipartUploadURLs 分片上传预签名URLs
+type MultipartUploadURLs struct {
+	UploadID   string              `json:"upload_id"`
+	PartURLs   map[int]string     `json:"part_urls"`
+	BucketName string            `json:"bucket_name"`
+	Key        string            `json:"key"`
+	Expiry     time.Time         `json:"expiry"`
+}
+
+// GenerateMultipartUploadURLs 生成分片上传预签名URLs
+func (p *Presigner) GenerateMultipartUploadURLs(ctx context.Context, bucket *bucket.BucketInfo, key string, partCount int) (*MultipartUploadURLs, error) {
+	// 初始化分片上传
+	createResp, err := bucket.Client.CreateMultipartUpload(ctx, &s3.CreateMultipartUploadInput{
+		Bucket: aws.String(bucket.Config.Name),
+		Key:    aws.String(key),
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to create multipart upload: %w", err)
+	}
+
+	presignClient := s3.NewPresignClient(bucket.Client)
+	partURLs := make(map[int]string)
+
+	// 为每个分片生成预签名URL
+	for i := 1; i <= partCount; i++ {
+		uploadPartInput := &s3.UploadPartInput{
+			Bucket:     aws.String(bucket.Config.Name),
+			Key:        aws.String(key),
+			UploadId:   createResp.UploadId,
+			PartNumber: aws.Int32(int32(i)),
+		}
+
+		presignRequest, err := presignClient.PresignUploadPart(ctx, uploadPartInput, func(opts *s3.PresignOptions) {
+			opts.Expires = p.uploadExpiry
+		})
+		if err != nil {
+			// 如果失败，中止分片上传
+			bucket.Client.AbortMultipartUpload(ctx, &s3.AbortMultipartUploadInput{
+				Bucket:   aws.String(bucket.Config.Name),
+				Key:      aws.String(key),
+				UploadId: createResp.UploadId,
+			})
+			return nil, fmt.Errorf("failed to generate part %d presigned URL: %w", i, err)
+		}
+
+		partURLs[i] = presignRequest.URL
+	}
+
+	// 注意：CompleteMultipartUpload 和 AbortMultipartUpload 需要在客户端直接调用
+	// 因为它们需要提供额外的参数（如Parts列表），不适合预签名
+	
+	return &MultipartUploadURLs{
+		UploadID:   *createResp.UploadId,
+		PartURLs:   partURLs,
+		BucketName: bucket.Config.Name,
+		Key:        key,
+		Expiry:     time.Now().Add(p.uploadExpiry),
+	}, nil
+}
diff --git a/test_s3_compatibility.py b/test_s3_compatibility.py
new file mode 100644
index 0000000..0c8044b
--- /dev/null
+++ b/test_s3_compatibility.py
@@ -0,0 +1,347 @@
+#!/usr/bin/env python3
+"""
+S3 Balance - S3兼容性测试脚本
+使用boto3 AWS SDK测试S3 Balance的S3兼容性
+"""
+
+import os
+import sys
+import time
+import hashlib
+import tempfile
+from datetime import datetime
+
+try:
+    import boto3
+    from botocore.client import Config
+except ImportError:
+    print("请先安装boto3: pip install boto3")
+    sys.exit(1)
+
+# S3 Balance服务配置
+S3_BALANCE_ENDPOINT = "http://localhost:8080"
+ACCESS_KEY = "AKIAIOSFODNN7EXAMPLE"
+SECRET_KEY = "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"
+
+# 测试配置
+TEST_BUCKET = "test-bucket-1"
+TEST_KEY_PREFIX = f"test-{int(time.time())}"
+
+def create_s3_client():
+    """创建S3客户端"""
+    return boto3.client(
+        's3',
+        endpoint_url=S3_BALANCE_ENDPOINT,
+        aws_access_key_id=ACCESS_KEY,
+        aws_secret_access_key=SECRET_KEY,
+        config=Config(
+            signature_version='s3v4',
+            s3={'addressing_style': 'path'}
+        ),
+        region_name='us-east-1'
+    )
+
+def test_list_buckets(s3_client):
+    """测试列出存储桶"""
+    print("\n1. 测试列出存储桶 (ListBuckets)...")
+    try:
+        response = s3_client.list_buckets()
+        buckets = response.get('Buckets', [])
+        print(f"   ✓ 找到 {len(buckets)} 个存储桶")
+        for bucket in buckets:
+            print(f"     - {bucket['Name']} (创建时间: {bucket['CreationDate']})")
+        return True
+    except Exception as e:
+        print(f"   ✗ 失败: {e}")
+        return False
+
+def test_upload_object(s3_client):
+    """测试上传对象"""
+    print(f"\n2. 测试上传对象 (PutObject)...")
+    
+    # 创建测试文件
+    test_data = b"Hello, S3 Balance! This is a test file."
+    test_key = f"{TEST_KEY_PREFIX}/test-upload.txt"
+    
+    try:
+        # 上传对象
+        response = s3_client.put_object(
+            Bucket=TEST_BUCKET,
+            Key=test_key,
+            Body=test_data,
+            ContentType='text/plain',
+            Metadata={'test': 'true', 'timestamp': str(int(time.time()))}
+        )
+        
+        etag = response.get('ETag', '').strip('"')
+        print(f"   ✓ 成功上传对象: {test_key}")
+        print(f"     ETag: {etag}")
+        return test_key
+    except Exception as e:
+        print(f"   ✗ 失败: {e}")
+        return None
+
+def test_list_objects(s3_client):
+    """测试列出对象"""
+    print(f"\n3. 测试列出对象 (ListObjects)...")
+    
+    try:
+        response = s3_client.list_objects_v2(
+            Bucket=TEST_BUCKET,
+            Prefix=TEST_KEY_PREFIX,
+            MaxKeys=10
+        )
+        
+        objects = response.get('Contents', [])
+        print(f"   ✓ 找到 {len(objects)} 个对象")
+        for obj in objects:
+            print(f"     - {obj['Key']} (大小: {obj['Size']} bytes, 修改时间: {obj['LastModified']})")
+        return True
+    except Exception as e:
+        print(f"   ✗ 失败: {e}")
+        return False
+
+def test_download_object(s3_client, key):
+    """测试下载对象"""
+    print(f"\n4. 测试下载对象 (GetObject)...")
+    
+    if not key:
+        print("   ⚠ 跳过: 没有可下载的对象")
+        return False
+    
+    try:
+        response = s3_client.get_object(
+            Bucket=TEST_BUCKET,
+            Key=key
+        )
+        
+        data = response['Body'].read()
+        content_type = response.get('ContentType', '')
+        content_length = response.get('ContentLength', 0)
+        
+        print(f"   ✓ 成功下载对象: {key}")
+        print(f"     内容类型: {content_type}")
+        print(f"     内容长度: {content_length} bytes")
+        print(f"     内容预览: {data[:50].decode('utf-8', errors='ignore')}...")
+        return True
+    except Exception as e:
+        print(f"   ✗ 失败: {e}")
+        return False
+
+def test_head_object(s3_client, key):
+    """测试获取对象元数据"""
+    print(f"\n5. 测试获取对象元数据 (HeadObject)...")
+    
+    if not key:
+        print("   ⚠ 跳过: 没有可查询的对象")
+        return False
+    
+    try:
+        response = s3_client.head_object(
+            Bucket=TEST_BUCKET,
+            Key=key
+        )
+        
+        print(f"   ✓ 成功获取对象元数据: {key}")
+        print(f"     内容长度: {response.get('ContentLength', 0)} bytes")
+        print(f"     内容类型: {response.get('ContentType', '')}")
+        print(f"     ETag: {response.get('ETag', '').strip('\"')}")
+        print(f"     最后修改: {response.get('LastModified', '')}")
+        return True
+    except Exception as e:
+        print(f"   ✗ 失败: {e}")
+        return False
+
+def test_multipart_upload(s3_client):
+    """测试分片上传（大文件）"""
+    print(f"\n6. 测试分片上传 (Multipart Upload)...")
+    
+    # 创建一个5MB的测试文件
+    test_key = f"{TEST_KEY_PREFIX}/test-multipart.bin"
+    part_size = 5 * 1024 * 1024  # 5MB per part
+    total_size = 10 * 1024 * 1024  # 10MB total
+    
+    try:
+        # 初始化分片上传
+        response = s3_client.create_multipart_upload(
+            Bucket=TEST_BUCKET,
+            Key=test_key,
+            ContentType='application/octet-stream'
+        )
+        upload_id = response['UploadId']
+        print(f"   ✓ 初始化分片上传，UploadId: {upload_id}")
+        
+        # 上传分片
+        parts = []
+        for i in range(2):  # 上传2个5MB的分片
+            part_number = i + 1
+            part_data = os.urandom(part_size)  # 生成随机数据
+            
+            part_response = s3_client.upload_part(
+                Bucket=TEST_BUCKET,
+                Key=test_key,
+                PartNumber=part_number,
+                UploadId=upload_id,
+                Body=part_data
+            )
+            
+            parts.append({
+                'ETag': part_response['ETag'],
+                'PartNumber': part_number
+            })
+            print(f"   ✓ 上传分片 {part_number}/2 完成")
+        
+        # 完成分片上传
+        s3_client.complete_multipart_upload(
+            Bucket=TEST_BUCKET,
+            Key=test_key,
+            UploadId=upload_id,
+            MultipartUpload={'Parts': parts}
+        )
+        
+        print(f"   ✓ 分片上传完成: {test_key}")
+        return test_key
+    except Exception as e:
+        print(f"   ✗ 失败: {e}")
+        return None
+
+def test_delete_object(s3_client, key):
+    """测试删除对象"""
+    print(f"\n7. 测试删除对象 (DeleteObject)...")
+    
+    if not key:
+        print("   ⚠ 跳过: 没有可删除的对象")
+        return False
+    
+    try:
+        s3_client.delete_object(
+            Bucket=TEST_BUCKET,
+            Key=key
+        )
+        
+        print(f"   ✓ 成功删除对象: {key}")
+        return True
+    except Exception as e:
+        print(f"   ✗ 失败: {e}")
+        return False
+
+def test_presigned_url(s3_client):
+    """测试预签名URL"""
+    print(f"\n8. 测试预签名URL...")
+    
+    test_key = f"{TEST_KEY_PREFIX}/test-presigned.txt"
+    
+    try:
+        # 生成上传预签名URL
+        upload_url = s3_client.generate_presigned_url(
+            'put_object',
+            Params={'Bucket': TEST_BUCKET, 'Key': test_key},
+            ExpiresIn=3600
+        )
+        print(f"   ✓ 生成上传预签名URL")
+        print(f"     URL: {upload_url[:80]}...")
+        
+        # 生成下载预签名URL
+        download_url = s3_client.generate_presigned_url(
+            'get_object',
+            Params={'Bucket': TEST_BUCKET, 'Key': test_key},
+            ExpiresIn=3600
+        )
+        print(f"   ✓ 生成下载预签名URL")
+        print(f"     URL: {download_url[:80]}...")
+        
+        return True
+    except Exception as e:
+        print(f"   ✗ 失败: {e}")
+        return False
+
+def cleanup(s3_client):
+    """清理测试数据"""
+    print(f"\n清理测试数据...")
+    
+    try:
+        # 列出所有测试对象
+        response = s3_client.list_objects_v2(
+            Bucket=TEST_BUCKET,
+            Prefix=TEST_KEY_PREFIX
+        )
+        
+        objects = response.get('Contents', [])
+        if objects:
+            # 删除所有测试对象
+            delete_objects = [{'Key': obj['Key']} for obj in objects]
+            s3_client.delete_objects(
+                Bucket=TEST_BUCKET,
+                Delete={'Objects': delete_objects}
+            )
+            print(f"   ✓ 删除了 {len(objects)} 个测试对象")
+        else:
+            print("   ✓ 没有需要清理的对象")
+        
+        return True
+    except Exception as e:
+        print(f"   ✗ 清理失败: {e}")
+        return False
+
+def main():
+    """主测试函数"""
+    print("=" * 60)
+    print("S3 Balance - S3兼容性测试")
+    print("=" * 60)
+    print(f"端点: {S3_BALANCE_ENDPOINT}")
+    print(f"测试桶: {TEST_BUCKET}")
+    print(f"测试前缀: {TEST_KEY_PREFIX}")
+    
+    # 创建S3客户端
+    s3_client = create_s3_client()
+    
+    # 执行测试
+    results = []
+    
+    # 基础测试
+    results.append(("ListBuckets", test_list_buckets(s3_client)))
+    
+    # 对象操作测试
+    uploaded_key = test_upload_object(s3_client)
+    results.append(("PutObject", uploaded_key is not None))
+    
+    results.append(("ListObjects", test_list_objects(s3_client)))
+    results.append(("GetObject", test_download_object(s3_client, uploaded_key)))
+    results.append(("HeadObject", test_head_object(s3_client, uploaded_key)))
+    
+    # 高级功能测试
+    # multipart_key = test_multipart_upload(s3_client)
+    # results.append(("MultipartUpload", multipart_key is not None))
+    
+    results.append(("PresignedURL", test_presigned_url(s3_client)))
+    
+    # 删除测试
+    results.append(("DeleteObject", test_delete_object(s3_client, uploaded_key)))
+    
+    # 清理
+    cleanup(s3_client)
+    
+    # 打印测试结果摘要
+    print("\n" + "=" * 60)
+    print("测试结果摘要")
+    print("=" * 60)
+    
+    passed = sum(1 for _, result in results if result)
+    total = len(results)
+    
+    for test_name, result in results:
+        status = "✓ 通过" if result else "✗ 失败"
+        print(f"{test_name:20} {status}")
+    
+    print("-" * 60)
+    print(f"总计: {passed}/{total} 测试通过")
+    
+    if passed == total:
+        print("\n🎉 所有测试通过！S3 Balance S3兼容性良好。")
+    else:
+        print(f"\n⚠️ 有 {total - passed} 个测试失败，请检查服务配置。")
+    
+    return 0 if passed == total else 1
+
+if __name__ == "__main__":
+    sys.exit(main())