package com.zy.exercise;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetAddress;

import java.util.Scanner;

public class send1 {

    public static void main(String[] args) throws Exception {

        DatagramSocket datagramSocket = new DatagramSocket();

        InetAddress byName = InetAddress.getByName("127.0.0.1");//如果别的主机要测试此处ip应该为192.168.219.61，即服务器的ip

        System.out.println("欢迎来到多人聊天室");

        Scanner scanner = new Scanner(System.in);

        String username=scanner.nextLine();

        while(true){

        System.out.println("请输入:");

        String str=scanner.nextLine();

        str=username+"说:"+str;

//        System.out.println(str);

        byte b[]=str.getBytes();

        DatagramPacket datagramPacket = new DatagramPacket(b, b.length, byName, 8888);

        datagramSocket.send(datagramPacket);

        if(str.equals("拜拜"))

        {

            System.out.println("退出");

            break;

        }

        }

        datagramSocket.close();

    }

}

package com.zy.exercise;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetAddress;

import java.net.SocketException;

public class server {

    //分发给该段网络的所有服务器

    public static void main(String[] args) throws Exception {

        DatagramSocket datagramSocket = new DatagramSocket(8888);

        byte b[]=new byte[1024];

        while(true){

        DatagramPacket datagramPacket = new DatagramPacket(b, b.length);

        datagramSocket.receive(datagramPacket);

        System.out.println(new String(b));

        for (int i = 1; i < 100; i++) {

            DatagramSocket datagramSocket2 = new DatagramSocket();

            InetAddress byName = InetAddress.getByName("192.168.219."+i);

            DatagramPacket datagramPacket2 = new DatagramPacket(b, b.length, byName, 10086);

            datagramSocket2.send(datagramPacket2);

        }

        }

//        datagramSocket.close();

    }

}

package com.zy.exercise;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.SocketException;

public class receive1 {

    public static void main(String[] args) throws Exception {

        System.out.println("xxxx聊天群");

        DatagramSocket datagramSocket = new DatagramSocket(10086);

        byte b[]=new byte[1024];

        while(true){

        DatagramPacket datagramPacket = new DatagramPacket(b, b.length);

        datagramSocket.receive(datagramPacket);

        System.out.println(new String(b));

        }

    }

}