Go语言实现UDP协议及TCP通讯

package main
 
import (
    "fmt"
    "net"
)
 
func main() {
    //1.建立监听端口
    listen, err := net.Listen("tcp", "0.0.0.0:20000")
    if err != nil {
        fmt.Println("listen failed, err:", err)
        return
    }
 
    fmt.Println("listen Start...:")
 
    for {
        //2.接收客户端的链接
        conn, err := listen.Accept()
        if err != nil {
            fmt.Printf("accept failed, err:%v\n", err)
            continue
        }
        //3.开启一个Goroutine，处理链接
        go process(conn)
    }
}
 
//处理请求，类型就是net.Conn
func process(conn net.Conn) {
 
    //处理结束后关闭链接
    defer conn.Close()
    for {
        var buf [128]byte
        n, err := conn.Read(buf[:])
        if err != nil {
            fmt.Printf("read from conn failed, err:%v", err)
            break
        }
        fmt.Printf("recv from client, content:%v\n", string(buf[:n]))
    }
 
}

package main
 
import (
    "bufio"
    "fmt"
    "net"
    "os"
    "strings"
)
 
func main() {
    //1.建立一个链接（Dial拨号）
    conn, err := net.Dial("tcp", "0.0.0.0:20000")
    if err != nil {
        fmt.Printf("dial failed, err:%v\n", err)
        return
    }
 
    fmt.Println("Conn Established...:")
 
    //读入输入的信息
    reader := bufio.NewReader(os.Stdin)
    for {
        data, err := reader.ReadString('\n')
        if err != nil {
            fmt.Printf("read from console failed, err:%v\n", err)
            break
        }
 
        data = strings.TrimSpace(data)
        //传输数据到服务端
        _, err = conn.Write([]byte(data))
        if err != nil {
            fmt.Printf("write failed, err:%v\n", err)
            break
        }
    }
}

package main
 
import (
    "fmt"
    "io"
    "net"
)
 
func main() {
    conn, err := net.Dial("tcp", "www.baidu.com:80")
    if err != nil {
        fmt.Printf("dial failed, err:%v\n", err)
        return
    }
 
    data := "GET / HTTP/1.1\r\n"
    data += "HOST: www.baidu.com\r\n"
    data += "connection: close\r\n"
    data += "\r\n\r\n"
 
    //写入数据
    _, err = io.WriteString(conn, data)
    if err != nil {
        fmt.Printf("wirte string failed, err:%v\n", err)
        return
    }
 
    var buf [1024]byte
    for {
        //读取返回的数据
        n, err := conn.Read(buf[:])
        if err != nil || n == 0 {
            break
        }
 
        fmt.Println(string(buf[:n]))
    }
}

package main
 
import (
    "fmt"
    "net"
)
 
func main() {
    //建立一个UDP的监听，这里使用的是ListenUDP，并且地址是一个结构体
    listen, err := net.ListenUDP("udp", &net.UDPAddr{
        IP:   net.IPv4(0, 0, 0, 0),
        Port: 8080,
    })
    if err != nil {
        fmt.Printf("listen failed, err:%v\n", err)
        return
    }
 
    for {
        var data [1024]byte
        //读取UDP数据
        count, addr, err := listen.ReadFromUDP(data[:])
        if err != nil {
            fmt.Printf("read udp failed, err:%v\n", err)
            continue
        }
 
        fmt.Printf("data:%s addr:%v count:%d\n", string(data[0:count]), addr, count)
        //返回数据
        _, err = listen.WriteToUDP([]byte("hello client"), addr)
        if err != nil {
            fmt.Printf("write udp failed, err:%v\n", err)
            continue
        }
    }
}

package main
 
import (
    "fmt"
    "net"
)
 
func main() {
    // 创建连接
    socket, err := net.DialUDP("udp4", nil, &net.UDPAddr{
        IP:   net.IPv4(127, 0, 0, 1),
        Port: 8080,
    })
    if err != nil {
        fmt.Println("连接失败!", err)
        return
    }
    defer socket.Close()
    // 发送数据
    senddata := []byte("hello server!")
    _, err = socket.Write(senddata)
    if err != nil {
        fmt.Println("发送数据失败!", err)
        return
    }
    // 接收数据
    data := make([]byte, 4096)
    read, remoteAddr, err := socket.ReadFromUDP(data)
    if err != nil {
        fmt.Println("读取数据失败!", err)
        return
    }
    fmt.Println(read, remoteAddr)
    fmt.Printf("%s\n", data)
}