golang网络编程例程

1. TCP Server

func startTcpServer() {
  listener, err := net.Listen("tcp", "127.0.0.1:9003")
  if err != nil {
    panic(err)
  }
  defer listener.Close()
  for {
    conn, err := listener.Accept()
    if err != nil {
      panic(err)
    }
    // go语言闭包函数对外部变量是以引用的方式引用，所以这里用函数传递conn
    go func(conn net.Conn) {
      for {
        buf := make([]byte, 1024)
        n, err := conn.Read(buf)
        if err != nil {
          fmt.Println(err)
          break
        }
        msg := string(buf[:n])
        fmt.Println(conn.RemoteAddr(), ":", msg)
        if msg == "quit" {
          conn.Write([]byte("Bye!"))
          conn.Close()
          break
        } else {
          conn.Write([]byte("OK"))
        }
      }
    }(conn)
  }
}

2. TCP Client

func startTcpClient() {
  conn, err := net.Dial("tcp", "127.0.0.1:9003")
  if err != nil {
    panic(err)
  }
  defer conn.Close()
  reader := bufio.NewReader(os.Stdin)
  for {
    data, _, _ := reader.ReadLine()
    n, err := conn.Write(data)
    if err != nil {
      fmt.Println(err)
      break
    }
    buf := make([]byte, 1024)
    n, err = conn.Read(buf)
    if err != nil {
      fmt.Println(err)
      break
    }
    fmt.Println("Rev:", string(buf[:n]))
    if string(data) == "quit" {
      break
    }
  }
}

3. UDP Server

func startUdpServer() {
  addr, err := net.ResolveUDPAddr("udp", "127.0.0.1:9003")
  if err != nil {
    panic(err)
  }
  conn, err := net.ListenUDP("udp", addr)
  if err != nil {
    panic(err)
  }
  defer conn.Close()
  buf := make([]byte, 1024)
  for {
    // UDP面向无连接的通信，UDP Server接收报文。
    n, remoteAddr, err := conn.ReadFromUDP(buf)
    if err != nil {
      fmt.Println(err)
      break
    }
    fmt.Println(remoteAddr, ": ", string(buf[:n]))
    conn.WriteToUDP([]byte("OK"), remoteAddr)
  }
}

4. UDP Client

func startUdpClient() {
  conn, err := net.Dial("udp", "127.0.0.1:9003")
  if err != nil {
    panic(err)
  }
  defer conn.Close()
  reader := bufio.NewReader(os.Stdin)
  for {
    data, _, _ := reader.ReadLine()
    n, err := conn.Write(data)
    if err != nil {
      fmt.Println(err)
      break
    }
    buf := make([]byte, 1024)
    n, err = conn.Read(buf)
    if err != nil {
      fmt.Println(err)
      break
    }
    fmt.Println("Rev:", string(buf[:n]))
    if string(data) == "quit" {
      break
    }
  }
}