1 package day12.lesson2.p1;
 2 
 3 import java.io.BufferedReader;
 4 import java.io.FileReader;
 5 import java.io.IOException;
 6 import java.io.InputStreamReader;
 7 import java.net.DatagramPacket;
 8 import java.net.DatagramSocket;
 9 import java.net.InetAddress;
10 import java.net.SocketException;
11 
12 /*
13 2.3 案例-UDP通信程序
14 
15     UDP发送数据：数据来自于键盘录入，直到输入的数据是886，发送数据结束
16     UDP接收数据：因为接收端不知道发送端什么时候停止发送，故采用死循环接收
17 
18  */
19 public class SendDemo {
20     public static void main(String[] args) throws IOException {
21         DatagramSocket ds = new DatagramSocket();
22 
23         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
24         String line;
25         while ((line=br.readLine()) != null){
26             if("886".equals(line)){
27                 break;
28             }
29 
30             byte[] bytes = line.getBytes();
31             DatagramPacket dp = new DatagramPacket(
32                     bytes,
33                     bytes.length,
34                     InetAddress.getByName("MSI-YUBABY"),
35                     12345
36             );
37 
38             ds.send(dp);
39         }
40 
41         ds.close();
42     }
43 }

 1 package day12.lesson2.p1;
 2 
 3 import java.io.IOException;
 4 import java.net.DatagramPacket;
 5 import java.net.DatagramSocket;
 6 
 7 public class ReceiveDemo {
 8     public static void main(String[] args) throws IOException {
 9         DatagramSocket ds = new DatagramSocket(12345);
10 
11         while (true){
12             byte[] bytes = new byte[1024];
13             DatagramPacket dp = new DatagramPacket(bytes, bytes.length);
14 
15             ds.receive(dp);
16 
17             System.out.println("接收到的数据：" + new String(
18                     dp.getData(),
19                     0,
20                     dp.getLength()
21             ));
22         }
23 
24 //        ds.close();
25         //启动一个ReceiveDemo-main，启动多个SendDemo-main，即可组成“聊天室”
26     }
27 }