package main

import (

	"fmt"

	"net"

)

func main() {

	// udp server

	listenUdp, err := net.ListenUDP("udp", &net.UDPAddr{

		IP:   net.IPv4(127,0,0,1),

		Port: 8080,

	})

	if err != nil {

		fmt.Println("ListenPacket fail err", err)

		return

	}

	defer listenUdp.Close()

	for {

		// 接收数据

		var buf [1024]byte

		n, addr, err := listenUdp.ReadFromUDP(buf[:])

		if err != nil {

			fmt.Println("ReadFromUDP fail err", err)

			continue

		}

		fmt.Printf("接收到客户端【%v】的数据：%s\n", addr, string(buf[:n]))

		// 发送数据

		msg := "server发送回来的数据" + string(buf[:n])

		num, err := listenUdp.WriteToUDP([]byte(msg), addr)

		if err != nil {

			fmt.Println("WriteToUDP fail err", num, err)

			continue

		}

	}

}

package main

import (

	"fmt"

	"net"

	"strings"

)

func main() {

	// udp client

	udpConn, err := net.DialUDP("udp", nil, &net.UDPAddr{

		IP:   net.IPv4(127,0,0,1),

		Port: 8080,

	})

	if err != nil {

		fmt.Println("DialUDP fail err", err)

		return

	}

	defer udpConn.Close()

	for {

		// 发送数据

		var data string

		fmt.Print("请输入要发送给服务器的数据：")

		fmt.Scanln(&data)

		if strings.ToUpper(data) == "Q" {

			break

		}

		sendData := []byte(data)

		_, err = udpConn.Write(sendData)

		if err != nil {

			fmt.Println("udp客户端Write fail err", err)

			return

		}

		// 接收数据

		buf := make([]byte, 4096)

		n, remoteAddr, err2 := udpConn.ReadFromUDP(buf[:])

		if err2 != nil {

			fmt.Println("udp客户端Read fail err", err2)

			return

		}

		fmt.Printf("data：%v, addr：%v\n", string(buf[:n]), remoteAddr)

	}

}