UDP

package com.fz.song.udp;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

/**
 * 先启动服务Client2,再启动Client
 */
public class Client2 {

    public static void main(String[] args) throws IOException {
        //创建一个udp的Socket
        DatagramSocket socket = new DatagramSocket(8000);
        //定义一个数组用于接收
        byte[] buff = new byte[100];
        //把数组给数据包
        DatagramPacket packet2 = new DatagramPacket(buff, 100);
        //接收
        socket.receive(packet2);
        //打印
        System.out.println(new String(buff,0,packet2.getLength()));

        String str = "ME TOO !";
        //把数据分装到数据包中
        DatagramPacket packet = new DatagramPacket(str.getBytes(), str.length(), packet2.getAddress(), packet2.getPort());
        socket.send(packet);

        socket.close();

    }
}

package com.fz.song.udp;

import java.io.IOException;
import java.net.*;

/**
 * upd
 */
public class Cline {

    public static void main(String[] args) throws IOException {
        //创建一个udp的Socket
        DatagramSocket socket = new DatagramSocket();
        //定义一个数据
        String str = "I LOVE YOU";
        //把数据封装到数据包中
        DatagramPacket packet = new DatagramPacket(str.getBytes(), str.length(), InetAddress.getByName("127.0.0.1"), 8000);
        //发送数据
        socket.send(packet);
        //定义一个数组用来接收数据
        byte[] buff = new byte[100];
        //把数组给这个数据包
        DatagramPacket packet2 = new DatagramPacket(buff, 100);
        //接收数据
        socket.receive(packet2);
        //打印数据
        System.out.println(new String(buff,0,packet2.getLength()));
        //关闭
        socket.close();

    }
}