Java UDP网络编程 - 最简单示例

 /**
  *UDPServer
  *@author Winty [email protected]
  *@version 2008-12-15
  */
 import java.io.*;
 import java.net.*;

 class UDPServer{
     public static void main(String[] args)throws IOException{
         DatagramSocket  server = new DatagramSocket(5050);

         byte[] recvBuf = new byte[100];
         DatagramPacket recvPacket
             = new DatagramPacket(recvBuf , recvBuf.length);

         server.receive(recvPacket);

         String recvStr = new String(recvPacket.getData() , 0 , recvPacket.getLength());
         System.out.println("Hello World!" + recvStr);

         int port = recvPacket.getPort();
         InetAddress addr = recvPacket.getAddress();
         String sendStr = "Hello ! I'm Server";
         byte[] sendBuf;
         sendBuf = sendStr.getBytes();
         DatagramPacket sendPacket
             = new DatagramPacket(sendBuf , sendBuf.length , addr , port );

         server.send(sendPacket);

         server.close();
     }
 }

 /**
  *UDPClient
  *@author Winty [email protected]
  *@version 2008-12-15
  */
 import java.io.*;
 import java.net.*;

 class UDPClient{
     public static void main(String[] args)throws IOException{
         DatagramSocket client = new DatagramSocket();

         String sendStr = "Hello! I'm Client";
         byte[] sendBuf;
         sendBuf = sendStr.getBytes();
         InetAddress addr = InetAddress.getByName("127.0.0.1");
         int port = 5050;
         DatagramPacket sendPacket
             = new DatagramPacket(sendBuf ,sendBuf.length , addr , port);

         client.send(sendPacket);

         byte[] recvBuf = new byte[100];
         DatagramPacket recvPacket
             = new DatagramPacket(recvBuf , recvBuf.length);
         client.receive(recvPacket);
         String recvStr = new String(recvPacket.getData() , 0 ,recvPacket.getLength());
         System.out.println("收到:" + recvStr);

         client.close();
     }
 }