[转]java 组播

1. 组播知识介绍： http://blog.csdn.net/happy_david/article/details/1569209

2. java 组播实现：来自： http://blog.csdn.net/a352193394/article/details/7395600

下面来演示一下使用Java Socket的组播类实现一个组播的小案例

首先是接收端

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1. package com.bird.test;
2. import java.net.DatagramPacket;
3. import java.net.InetAddress;
4. import java.net.MulticastSocket;
5. import java.util.Date;
6. /**
7. * 组播的客户端
8. * @author Bird
9. *
10. */
11. public class MulticastReceive {
12. public static void main(String[] args) throws Exception {
13. test();
14. }
15. public static void test() throws Exception{
16. InetAddress group = InetAddress.getByName("224.0.0.2");//组播地址
17. int port = 8888;
18. MulticastSocket msr = null;//创建组播套接字
19. try {
20. msr = new MulticastSocket(port);
21. msr.joinGroup(group);//加入连接
22. byte[] buffer = new byte[8192];
23. System.out.println("接收数据包启动！(启动时间: "+new Date()+")");
24. while(true){
25. //建立一个指定缓冲区大小的数据包
26. DatagramPacket dp = new DatagramPacket(buffer, buffer.length);
27. msr.receive(dp);
28. String s = new String(dp.getData(),0,dp.getLength());
29. //解码组播数据包
30. System.out.println(s);
31. }
32. } catch (Exception e) {
33. e.printStackTrace();
34. }finally{
35. if(msr!=null){
36. try {
37. msr.leaveGroup(group);
38. msr.close();
39. } catch (Exception e2) {
40. // TODO: handle exception
41. }
42. }
43. }
44. }
45. }

然后是发送端

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1. package com.bird.test;
2. import java.net.DatagramPacket;
3. import java.net.InetAddress;
4. import java.net.MulticastSocket;
5. import java.util.Date;
6. /**
7. * 组播的服务端
8. * @author Bird
9. *
10. */
11. public class MulticastSender {
12. public static void server() throws Exception{
13. InetAddress group = InetAddress.getByName("224.0.0.2");//组播地址
14. int port = 8888;
15. MulticastSocket mss = null;
16. try {
17. mss = new MulticastSocket(port);
18. mss.joinGroup(group);
19. System.out.println("发送数据包启动！（启动时间"+new Date()+")");
20. while(true){
21. String message = "Hello "+new Date();
22. byte[] buffer = message.getBytes();
23. DatagramPacket dp = new DatagramPacket(buffer, buffer.length,group,port);
24. mss.send(dp);
25. System.out.println("发送数据包给 "+group+":"+port);
26. Thread.sleep(1000);
27. }
28. } catch (Exception e) {
29. e.printStackTrace();
30. }finally{
31. try {
32. if(mss!=null){
33. mss.leaveGroup(group);
34. mss.close();
35. }
36. } catch (Exception e2) {
37. // TODO: handle exception
38. }
39. }
40. }
41. public static void main(String[] args) throws Exception {
42. server();
43. }
44. }

通过开启多个接收端，然后开启发送端，就可以实现组播的效果