[网络协议]【网络编程】用Java写在线聊天工具，学完用一年时间写个QQ（三）

一：客户端（Udp）

package com.iyunsir.lesson03_udp;


import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

// 不需要连接服务器
public class UdpClientDemo01 {
    public static void main(String[] args) throws Exception {
        // 1.建立一个socket
        DatagramSocket socket = new DatagramSocket();

        // 2.建个包
        String msg = "你好，服务器!";

        // 3.发送给谁
        InetAddress localhost = InetAddress.getByName("localhost");
        int port = 9090;

        // 4.数据,数据的长度起始,要发给谁
        DatagramPacket packet = new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port);

        // 5.发送包
        socket.send(packet);

        // 6.关闭流
        socket.close();
    }



}

二：服务端（Udp）

package com.iyunsir.lesson03_udp;

import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class UdpServerDemo01 {
    public static void main(String[] args) throws Exception {
        // 1.开放端口
        DatagramSocket socket = new DatagramSocket(9090);
        // 2.接收数据包
        byte[] buffer = new byte[1024];
        DatagramPacket packet = new DatagramPacket(buffer,0,buffer.length);

        socket.receive(packet); //阻塞接收

        System.out.println(packet.getAddress().getHostAddress());
        System.out.println(new String(packet.getData(),0, packet.getLength()));

        // 3.关闭连接

    }
}

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