Java UDP 网络编程示例

    <p>分别创建两个文件，UDPServer.java 和 UDPClient.java，先运行 UDPServer，开始监<span style="display: none;">|敏感词分隔符|</span>听。再运行 UDPClient，在 UDPClient 中输入字符串，UDPServer 接收到后将它转换成大写，传回 UDPClient。</p>

UDPServer.java：

import java.io.*;
import java.net.*;
public class UDPServer {
public static void main(String args[]) throws Exception {
DatagramSocket serverSocket = new DatagramSocket(9876);
byte[] receiveData = new byte[1024];
byte[] sendData = new byte[1024];
	while(true) {
		DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
		serverSocket.receive(receivePacket);
		String sentence = new String(receivePacket.getData());
		InetAddress IPAddress = receivePacket.getAddress();
		int port = receivePacket.getPort();
		String capitalizedSentence = "Your port: " + port + "\n" + sentence.toUpperCase();
		sendData = capitalizedSentence.getBytes();
		DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port);
		serverSocket.send(sendPacket);
	}
}

}

UDPClient.java：

import java.io.*;
import java.net.*;
public class UDPClient {
public static void main(String args[]) throws Exception {
BufferedReader inFromUser =
new BufferedReader(new InputStreamReader(System.in));
DatagramSocket clientSocket = new DatagramSocket();
InetAddress IPAddress = InetAddress.getByName("localhost");
byte[] sendData = new byte[1024];
byte[] receiveData = new byte[1024];
String sentence = inFromUser.readLine();
sendData = sentence.getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 9876);
clientSocket.send(sendPacket);
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
clientSocket.receive(receivePacket);
String modifiedSentence = new String(receivePacket.getData());
System.out.println("FROM SERVER: " + modifiedSentence);
clientSocket.close();
}
}