. 使用UDP协议编写一个网络程序，设置接收端程序的监听端口是8001，发送端发送的数据是“Hello, world”。

发送方

test 1

package 网络编程;


import java.net.*;
public class Test1 {


public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
byte[] buf=new byte[1024];
DatagramSocket ds=new DatagramSocket(8001);
DatagramPacket dp=new DatagramPacket(buf,1024);
ds.receive(dp);
String str=new String(dp.getData(),0,dp.getLength());
System.out.println(str);
ds.close();
}


}

接收方

test 2

package 网络编程;
import java.net.*;


public class Test2 {


public static void main(String[] args) throws Exception{
// TODO Auto-generated method stub
DatagramSocket ds=new DatagramSocket(3000);
String str="Hello World!";
DatagramPacket dp=new DatagramPacket(str.getBytes(),str.length(),
InetAddress.getByName("localhost"),8001);
ds.send(dp);
ds.close();

}


}