DatagramSocket(UDP协议)

一、UDP协议无状态协议，不可靠协议，单向通信，数据包

广播方：

 1 import java.io.IOException;
 2 import java.net.DatagramPacket;
 3 import java.net.DatagramSocket;
 4 import java.net.InetAddress;
 5 import java.sql.SQLException;
 6
 7 public class Broadcast {
 8
 9     public static void main(String[] args) throws IOException, ClassNotFoundException, SQLException {
10         DatagramSocket ds=new DatagramSocket();
11         InetAddress address=InetAddress.getByName("123.123.123.123");//输入本服务器IP
12         byte [] bs="广播一条通知：".getBytes();
13         DatagramPacket dp=new DatagramPacket(bs, bs.length,address,6666);//端口号自定义
14         ds.send(dp);
15         ds.close();
16     }
17 }

听众方：

 1 import java.io.IOException;
 2 import java.net.DatagramPacket;
 3 import java.net.DatagramSocket;
 4 import java.net.InetAddress;
 5 import java.sql.SQLException;
 6 public class UDPClient {
 7
 8     public static void main(String[] args)  throws IOException{
 9         DatagramSocket ds=new DatagramSocket(6666);
10         byte[] bs=new byte[65536];
11         DatagramPacket dp=new DatagramPacket(bs, bs.length);
12         ds.receive(dp);
13         String s=new String(dp.getData());
14         System.out.println("收到的数据为："+s.substring(0,dp.getLength()/2)+";收到的位移偏量为："+dp.getOffset()+";有效长度为："+dp.getLength());
15
16     }
17 }