Add example implementations for etcd, PostgreSQL, and Redis clients demonstrating automatic reconnection management and basic operations.

examples/postgres_example.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/blueocean-go/reconnect"
+)
+
+func main() {
+	// PostgreSQL连接字符串
+	dsn := "host=localhost user=postgres password=postgres dbname=testdb sslmode=disable"
+
+	// 创建重连配置
+	config := reconnect.DefaultConfig()
+	config.RetryInterval = 3 * time.Second
+	config.MaxRetries = 0 // 无限重试
+	config.OnReconnect = func() {
+		fmt.Println("PostgreSQL重连成功!")
+	}
+	config.OnDisconnect = func(err error) {
+		fmt.Printf("PostgreSQL连接断开: %v\n", err)
+	}
+
+	// 创建重连管理器
+	manager := reconnect.PostgresManager(
+		dsn,
+		25,             // maxConnections
+		5,              // maxIdleConnections
+		30*time.Minute, // maxConnectionAge
+		config,
+	)
+
+	// 启动连接
+	ctx := context.Background()
+	if err := manager.Start(ctx); err != nil {
+		log.Fatalf("启动失败: %v", err)
+	}
+	defer manager.Stop()
+
+	// 获取数据库连接并使用
+	pgClient := reconnect.NewPostgresClient(dsn, 25, 5, 30*time.Minute)
+	if err := pgClient.Connect(ctx); err != nil {
+		log.Fatalf("连接失败: %v", err)
+	}
+
+	db := pgClient.GetDB()
+	if db == nil {
+		log.Fatal("数据库连接为空")
+	}
+
+	// 使用数据库连接
+	var version string
+	err := db.QueryRow("SELECT version()").Scan(&version)
+	if err != nil {
+		log.Printf("查询失败: %v", err)
+	} else {
+		fmt.Printf("PostgreSQL版本: %s\n", version)
+	}
+
+	// 保持运行
+	select {}
+}