Comment la programmation réseau Java utilise-t-elle UDP pour la communication sans connexion ?

import java.net.*; public class UDPServer { public static void main(String[] args) throws Exception { // 创建一个DatagramSocket，监听6789端口 DatagramSocket serverSocket = new DatagramSocket(6789); // 持续监听传入的数据报 while (true) { // 创建一个数据报对象来接收数据 DatagramPacket receivePacket = new DatagramPacket(new byte[1024], 1024); // 接收数据报 serverSocket.receive(receivePacket); // 获取客户端地址和端口 InetAddress clientAddress = receivePacket.getAddress(); int clientPort = receivePacket.getPort(); // 将数据报转换为字符串 String message = new String(receivePacket.getData(), 0, receivePacket.getLength()); System.out.println("收到来自 " + clientAddress + ":" + clientPort + " 的消息：" + message); // 创建一个数据报对象来响应客户端 DatagramPacket responsePacket = new DatagramPacket( ("响应：" + message).getBytes(), ("响应：" + message).getBytes().length, clientAddress, clientPort ); // 发送响应 serverSocket.send(responsePacket); } // 关闭服务器套接字 serverSocket.close(); } }

import java.net.*; public class UDPClient { public static void main(String[] args) throws Exception { // 创建一个DatagramSocket DatagramSocket clientSocket = new DatagramSocket(); // 获取要发送的消息 String message = "你好，世界！"; // 将消息转换为字节数组 byte[] messageBytes = message.getBytes(); // 创建一个数据报对象，将消息发送到服务器的6789端口 DatagramPacket sendPacket = new DatagramPacket( messageBytes, messageBytes.length, InetAddress.getByName("localhost"), // 服务器地址 6789 // 服务器端口 ); // 发送数据报 clientSocket.send(sendPacket); // 创建一个数据报对象来接收服务器的响应 DatagramPacket receivePacket = new DatagramPacket(new byte[1024], 1024); // 接收响应 clientSocket.receive(receivePacket); // 将响应转换为字符串 String response = new String(receivePacket.getData(), 0, receivePacket.getLength()); // 打印响应 System.out.println("收到服务器的响应：" + response); // 关闭客户端套接字 clientSocket.close(); } }