java UDP小程序

 1 package com.socket.udp;
 2 
 3 import java.io.ByteArrayInputStream;
 4 import java.io.ByteArrayOutputStream;
 5 import java.io.DataInputStream;
 6 import java.io.DataOutputStream;
 7 import java.io.IOException;
 8 import java.net.DatagramPacket;
 9 import java.net.DatagramSocket;
10 import java.net.InetSocketAddress;
11 import java.net.SocketException;
12 
13 import org.junit.Test;
14 
15 public class TestUDP {
16     @Test
17     public void testUDPServer(){
18         try {
19             byte[] buf = new byte[1024];
20             DatagramPacket dp = new DatagramPacket(buf,buf.length); 
21             DatagramSocket ds = new DatagramSocket(5678);
22             while(true){
23                 ds.receive(dp);//阻塞时方法
24                 ByteArrayInputStream bais = new ByteArrayInputStream(buf);
25                 DataInputStream dis = new DataInputStream(bais);
26                 System.out.println(dis.readLong());
27             }
28         } catch (SocketException e) {
29             e.printStackTrace();
30         } catch (IOException e) {
31             e.printStackTrace();
32         }
33     }
34     
35     @Test
36     public void testUDPClient(){
37         try {
38             long n = 99999L;
39             ByteArrayOutputStream baos = new ByteArrayOutputStream();
40             DataOutputStream dos = new DataOutputStream(baos);
41             dos.writeLong(n);
42             byte[] buf = baos.toByteArray();
43             DatagramPacket dp = new DatagramPacket(buf,buf.length,new InetSocketAddress("127.0.0.1",5678));
44             DatagramSocket ds = new DatagramSocket(9999);
45             ds.send(dp);
46             ds.close();
47         } catch (SocketException e) {
48             e.printStackTrace();
49         } catch (IOException e) {
50             e.printStackTrace();
51         }
52     }
53 }