package com.sxt.udp;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;

public class UdpClient {
    public static void main(String[] args) throws Exception {
        System.out.println("客户端启动中.......");
        //使用DatagramSocket
        DatagramSocket client = new DatagramSocket(8888);
        
        String str=new String("你好呀呀，UDP");
        byte[] datas = str.getBytes();
        
        DatagramPacket packet = new DatagramPacket(datas,0, datas.length,
                new InetSocketAddress("127.0.0.1",9999));
        
        client.send(packet);
        
        client.close();
    }
}

package com.sxt.udp;

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

public class UdpServer {
    public static void main(String[] args) throws Exception {
        System.out.println("接收端启动中.......");
        //使用DatagramSocket
        DatagramSocket server = new DatagramSocket(9999);
        
        byte[] datas = new byte[1024*60];
        
        DatagramPacket packet = new DatagramPacket(datas,0, datas.length);
        
        server.receive(packet);
        
        datas = packet.getData();
        
        System.out.println(new String(datas,0,datas.length));
        
        server.close();
    }
}

运行结果：（先启动服务器，再启动客户端）