发送程序:

import java.net.*;
public class UdpSend
{
 public static void main(String[] args) throws Exception
 {
  DatagramSocket ds=new DatagramSocket();
  String str="hello world";
  DatagramPacket dp=new DatagramPacket(str.getBytes(),str.length(),Inet4Address.getByName("172.16.203.25"),3000);
  ds.send(dp);
  ds.close();
 }
}

接收程序:

import java.net.*;
public class UdpRecv
{
 public static void main(String[] args) throws Exception
 {
  DatagramSocket ds=new DatagramSocket(3000);
  byte[] buf=new byte [1024];
  DatagramPacket dp=new DatagramPacket(buf,1024);
  ds.receive(dp);
   String strRecv=new String(dp.getData(),0,dp.getLength())+
    "from"+
 dp.getAddress().getHostAddress()+":"+dp.getPort();
   System.out.print(strRecv);
   ds.close();
 }
}