UdpSend.java

import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.net.SocketException; import java.net.UnknownHostException; public class UdpSend {
   public static void main(String args[]){
           DatagramSocket ds = null;         DatagramPacket dp = null; try{
               ds = new DatagramSocket(3000); //实例化一个UDP的套接字并绑定3000绑定         }catch(SocketException e){
           }         String str = "hello world"; try{
               dp = new DatagramPacket(str.getBytes(),str.length(),InetAddress.getByName("localhost"),9000);         } catch(UnknownHostException ex1){
           } try{
               ds.send(dp);   //发送数据到本机的9000                     }catch(IOException e){
           }         ds.close();     } }

 

UdpReceive.java

import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; public class UdpReceive {
   public static void main(String args[]){
           DatagramSocket ds = null; //创建一个套接字对象         byte[] buf = new byte[1024]; //实例化一个数组         DatagramPacket dp = null; //创建一个套接字结构对象         try{
               ds = new DatagramSocket(9000);//实例化并绑定端口                } catch(IOException e){
           }         dp = new DatagramPacket(buf,1024); try{
               ds.receive(dp);//接收数据并存放在dp中         } catch(IOException e2){
           }         String str = new String(dp.getData(),0,dp.getLength()) +" from " +dp.getAddress().getHostAddress()+":"+dp.getPort();         System.out.println(str); //打印接收到的内容         ds.close();     } }