java 网络知识 + 多线程问题

服务器：

package p1007;import java.io.*;
import java.net.*;
import java.util.Random;public class Server {public static void main(String[] args) {int port = 12345; // 服务端口try (ServerSocket serverSocket = new ServerSocket(port)) {System.out.println("服务器已启动，等待客户端连接...");while (true) {Socket socket = serverSocket.accept();System.out.println("客户端连接: " + socket.getInetAddress());new ClientHandler(socket).start(); // 为每个客户端连接启动一个新线程}} catch (IOException e) {e.printStackTrace();}}
}class ClientHandler extends Thread {private Socket socket;public ClientHandler(Socket socket) {this.socket = socket;}@Overridepublic void run() {try (BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));PrintWriter out = new PrintWriter(socket.getOutputStream(), true)) {Random random = new Random();int num1 = random.nextInt(100);int num2 = random.nextInt(100);int correctAnswer = num1 + num2;out.println("请计算: " + num1 + " + " + num2 + " = ?");String inputLine;while ((inputLine = in.readLine()) != null) {try {int userAnswer = Integer.parseInt(inputLine);if (userAnswer == correctAnswer) {out.println("回答正确！连接结束。");System.out.println(socket.getInetAddress()+"回答正确！连接结束。");out.println("结束");System.out.println(socket.getInetAddress()+"结束");break;} else {System.out.println(socket.getInetAddress()+"错误，请再试一次：");out.println("错误，请再试一次：");}} catch (NumberFormatException e) {out.println("无效输入，请输入一个数字。");System.out.println(socket.getInetAddress()+"无效输入，请输入一个数字。");}}} catch (IOException e) {e.printStackTrace();} finally {try {socket.close();} catch (IOException e) {e.printStackTrace();}}}
}

客服机：

package p1007;import java.io.*;
import java.net.*;public class Client {public static void main(String[] args) {String serverAddress = "localhost"; // 服务器地址int port = 12345; // 服务器端口try (Socket socket = new Socket(serverAddress, port);BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));PrintWriter out = new PrintWriter(socket.getOutputStream(), true);BufferedReader userInput = new BufferedReader(new InputStreamReader(System.in))) {String serverMessage;while ((serverMessage = in.readLine()) != null) {System.out.println("服务器: " + serverMessage);if(serverMessage.equals("回答正确！连接结束。"))break;System.out.print("您的答案: ");String answer = userInput.readLine();out.println(answer); // 发送用户的答案}} catch (IOException e) {e.printStackTrace();}System.out.println("结束");}
}