19. UDP 编程

import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.SocketException;public class Udp {public static void main(String[] args) {try {DatagramSocket ds = new DatagramSocket(9998);String str = "1234";DatagramPacket dp = new DatagramPacket(str.getBytes(), str.length(), InetAddress.getByName("localhost"),9999);ds.send(dp);byte[] buff = new byte[1024];DatagramPacket dp2 = new DatagramPacket(buff, 1024);ds.receive(dp2);String result = new String(dp2.getData(), 0, dp2.getLength());ds.close();} catch (SocketException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}