如何在 Go 的 net 包中检测 TCP 连接是否已关闭

package main

import (
    "fmt"
    "io"
    "log"
    "net"
    "time"
)

func handleConnection(c net.Conn, id string, logger *log.Logger) {
    defer c.Close()

    one := make([]byte, 1)
    c.SetReadDeadline(time.Now()) // 设置立即超时

    if _, err := c.Read(one); err == io.EOF {
        logger.Printf("DEBUG: %s detected closed LAN connection", id)
        return
    } else if err != nil {
        // 检测是否是超时错误
        if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
            // 连接正常，重置读取超时时间
            c.SetReadDeadline(time.Now().Add(10 * time.Millisecond))
            // 这里可以继续处理连接
            fmt.Println("Timeout occurred, connection is likely still open")
            return
        } else {
            logger.Printf("ERROR: Error reading from connection: %v", err)
            return
        }
    } else {
        // 读取到数据，重置读取超时时间
        var zero time.Time
        c.SetReadDeadline(zero) // 或者设置为一个合理的超时时间
        fmt.Printf("Received data: %v\n", one)
        // 这里可以继续处理接收到的数据
    }
}

func main() {
    listener, err := net.Listen("tcp", ":8080")
    if err != nil {
        log.Fatal(err)
    }
    defer listener.Close()

    logger := log.Default()
    id := "client1"

    for {
        conn, err := listener.Accept()
        if err != nil {
            log.Println(err)
            continue
        }

        go handleConnection(conn, id, logger)
    }
}