package UDP;import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.SocketException;//接收端public class TestUdpR {    public static void main(String[] args) throws IOException {        //建立UDP的服务        DatagramSocket socket = new DatagramSocket(9000);        //准备空数据包用于存储数据        byte buf[] = new byte[1024];        DatagramPacket dataPacket = new DatagramPacket(buf, buf.length);        //调用UDP服务接收数据        socket.receive(dataPacket);        System.out.println(new String(buf, 0, dataPacket.getLength()));//getLength()获取接收数据的长度        //关闭资源        socket.close();            }}

package UDP;import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.SocketException;//发送端public class TestUdpT {    public static void main(String[] args) throws IOException {        //建立UDP的服务        DatagramSocket dgs = new DatagramSocket();        //准备数据，把数据封装到数据包中        String data = "This is UDP Packet";        //创建一个数据包        DatagramPacket packet = new DatagramPacket(data.getBytes(), data.getBytes().length,InetAddress.getLocalHost(),9000);        //调用UDP的服务发送数据        dgs.send(packet);        //关闭资源        dgs.close();    }}