一个简单的Java UDP协议通信的例子

一个简单的Java UDP协议通信的例子

server：

import java.net.*; public class UDPServer {     private static final int PORT = 5000;     private DatagramSocket dataSocket;     private DatagramPacket dataPacket;     private byte receiveByte[];     private String receiveStr;     public UDPServer() {         Init();     }     public void Init() {         try {             dataSocket = new DatagramSocket(PORT);             receiveByte = new byte[1024];             dataPacket = new DatagramPacket(receiveByte, receiveByte.length);             receiveStr = "";             int i = 0;             while (i == 0)// 无数据，则循环             {                 dataSocket.receive(dataPacket);                 i = dataPacket.getLength();                 // 接收数据                 if (i > 0) {                     // 指定接收到数据的长度,可使接收数据正常显示,开始时很容易忽略这一点                     receiveStr = new String(receiveByte, 0, dataPacket.getLength());                     System.out.println(receiveStr);                     i = 0;// 循环接收                 }             }         } catch (Exception e) {             e.printStackTrace();         }     }     public static void main(String args[]) {         new UDPServer();     } }

client：

import java.io.*; import java.net.*; public class UDPClient {     private static final int PORT = 4561;     private DatagramSocket dataSocket;     private DatagramPacket dataPacket;     private byte sendDataByte[];     private String sendStr;     public UDPClient() {         Init();     }     public void Init() {         try {             // 指定端口号，避免与其他应用程序发生冲突             dataSocket = new DatagramSocket(PORT+1);             sendDataByte = new byte[1024];             sendStr = "UDP方式发送数据";             sendDataByte = sendStr.getBytes();             dataPacket = new DatagramPacket(sendDataByte, sendDataByte.length,                     InetAddress.getByName("localhost"), PORT);             dataSocket.send(dataPacket);         } catch (SocketException se) {             se.printStackTrace();         } catch (IOException ie) {             ie.printStackTrace();         }     }     public static void main(String args[]) {         new UDPClient();     } }