即时通信 (广播)

 1 package Test;
 2 
 3 import java.io.IOException;
 4 import java.net.DatagramPacket;
 5 import java.net.InetAddress;
 6 import java.net.MulticastSocket;
 7 import java.util.Scanner;
 8 
 9 
10 public class GuangboSrc {
11 
12     /**
13      * @param args
14      * @throws IOException 
15      */
16     public static void main(String[] args) throws IOException {
17 //        创建广播地址
18         InetAddress ip=InetAddress.getByName("230.0.0.1");
19 //        将创建的广播加入到广播组中
20 
21         MulticastSocket multicastSocket=new MulticastSocket(55555);
22         multicastSocket.joinGroup(ip);
23 //        创建广播的数据包
24         System.out.println("请输入要广播的内容：");
25         Scanner scan=new Scanner(System.in);
26         String str=scan.next();
27         byte[]b=str.getBytes();
28         DatagramPacket pancket =new DatagramPacket(b, b.length, ip,55555);
29 //        发送广播
30         multicastSocket.send(pancket);
31     }
32 
33 }

发送端

 1 package Test;
 2 
 3 import java.io.IOException;
 4 import java.net.DatagramPacket;
 5 import java.net.InetAddress;
 6 import java.net.MulticastSocket;
 7 import java.net.UnknownHostException;
 8 
 9 public class GuanagboDes {
10 //    接受广播
11     public static void main(String[] args) throws IOException {
12         // TODO Auto-generated method stub
13 //        广播地址
14         InetAddress ip=InetAddress.getByName("230.0.0.1");
15 //        将广播地址加入到广播组中
16         MulticastSocket multicastSocket=new MulticastSocket(55555);
17         multicastSocket.joinGroup(ip);
18         
19 //        接收数据报
20         byte[]b=new byte[1024];
21         DatagramPacket packet =new DatagramPacket(b,b.length);
22 //        接受广播
23         multicastSocket.receive(packet);
24 //        展示广播内容
25         String str=new String(packet.getData(),0,packet.getLength());
26         System.out.println("接受到的广播信息是："+str);
27         
28         
29     }
30 
31 }

接收端