go语言中的udp协议及TCP通讯实现示例

package main
import (
	"fmt"
	"net"
)
func main() {
	// 创建监听
	socket, err := net.ListenUDP("udp4", &net.UDPAddr{
		IP:   net.IPv4(0, 0, 0, 0),
		Port: 8080,
	})
	if err != nil {
		fmt.Println("监听失败!", err)
		return
	}
	defer socket.Close()
	for {
		// 读取客户端传来的数据
		data := make([]byte, 4096)
		read, remoteAddr, err := socket.ReadFromUDP(data)
		if err != nil {
			fmt.Println("读取数据失败!", err)
			continue
		}
		fmt.Println(read, remoteAddr)
		fmt.Printf("%snn", data)
		//发送数据,告诉客户端已收到
		senddata := []byte("hello client!")
		_, err = socket.WriteToUDP(senddata, remoteAddr)
		if err != nil {
			return
			fmt.Println("发送数据失败!", err)
		}
	}
}

package main
import (
	"fmt"
	"net"
)
func main() {
	// 创建连接
	socket, err := net.DialUDP("udp4", nil, &net.UDPAddr{
		IP:   net.IPv4(0, 0, 0, 0),
		Port: 8080,
	})
	if err != nil {
		fmt.Println("连接失败!", err)
		return
	}
	defer socket.Close()
	// 发送给服务端数据
	senddata := []byte("hello server!")
	_, err = socket.Write(senddata)
	if err != nil {
		fmt.Println("发送数据失败!", err)
		return
	}
	// 接收客户端的数据
	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("%sn", data)
}

package main
import (
	"fmt"
	"net"
)
func main() {
	//监听
	listener, err := net.Listen("tcp", "127.0.0.1:8000")
	if err != nil {
		fmt.Println("err = ", err)
		return
	}
	defer listener.Close()
	//阻塞等待用户链接
	conn, err := listener.Accept()
	if err != nil {
		fmt.Println("err = ", err)
		return
	}
	//接收用户的请求
	buf := make([]byte, 1024) //1024大小的缓冲区
	n, err1 := conn.Read(buf)
	if err1 != nil {
		fmt.Println("err1 = ", err1)
		return
	}
	fmt.Println("buf = ", string(buf[:n]))
	defer conn.Close() //关闭当前用户链接
}

package main
import (
	"fmt"
	"net"
)
func main() {
	//主动连接服务器
	conn, err := net.Dial("tcp", "127.0.0.1:8000")
	if err != nil {
		fmt.Println("err = ", err)
		return
	}
	defer conn.Close()
	//发送数据
	conn.Write([]byte("are u ok?"))
}

package main
import (
	"fmt"
	"net"
	"strings"
)
//处理用户请求
func HandleConn(conn net.Conn) {
	//函数调用完毕，自动关闭conn
	defer conn.Close()
	//获取客户端的网络地址信息
	addr := conn.RemoteAddr().String()
	fmt.Println(addr, " conncet sucessful")
	buf := make([]byte, 2048)
	for {
		//读取用户数据
		n, err := conn.Read(buf)
		if err != nil {
			fmt.Println("err = ", err)
			return
		}
		fmt.Printf("[%s]: %sn", addr, string(buf[:n]))
		fmt.Println("len = ", len(string(buf[:n])))
		//if "exit" == string(buf[:n-1]) { //nc测试
		if "exit" == string(buf[:n-2]) { //自己写的客户端测试, 发送时，多了2个字符, "rn"
			fmt.Println(addr, " exit")
			return
		}
		//把数据转换为大写，再给用户发送
		conn.Write([]byte(strings.ToUpper(string(buf[:n]))))
	}

}
func main() {
	//监听
	listener, err := net.Listen("tcp", "127.0.0.1:8000")
	if err != nil {
		fmt.Println("err = ", err)
		return
	}
	defer listener.Close()
	//接收多个用户
	for {
		conn, err := listener.Accept()
		if err != nil {
			fmt.Println("err = ", err)
			return
		}
		//处理用户请求, 新建一个协程
		go HandleConn(conn)
	}
}

package main
import (
	"fmt"
	"net"
	"os"
)
func main() {
	//主动连接服务器
	conn, err := net.Dial("tcp", "127.0.0.1:8000")
	if err != nil {
		fmt.Println("net.Dial err = ", err)
		return
	}
	//main调用完毕，关闭连接
	defer conn.Close()
	go func() {
		//从键盘输入内容，给服务器发送内容
		str := make([]byte, 1024)
		for {
			n, err := os.Stdin.Read(str) //从键盘读取内容， 放在str
			if err != nil {
				fmt.Println("os.Stdin. err = ", err)
				return
			}
			//把输入的内容给服务器发送
			conn.Write(str[:n])
		}
	}()
	//接收服务器回复的数据
	//切片缓冲
	buf := make([]byte, 1024)
	for {
		n, err := conn.Read(buf) //接收服务器的请求
		if err != nil {
			fmt.Println("conn.Read err = ", err)
			return
		}
		fmt.Println(string(buf[:n])) //打印接收到的内容, 转换为字符串再打印
	}
}