src/MathLearningApp.java

@@ -0,0 +1,21 @@
+import controller.NavigationController;
+import javax.swing.UIManager;
+import javax.swing.SwingUtilities;
+
+public class MathLearningApp {
+    public static void main(String[] args) {
+        // Set system look and feel
+        try {
+            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+
+        // Start the application
+        SwingUtilities.invokeLater(() -> {
+            // 获取 NavigationController 实例并显示登录界面
+            NavigationController navigationController = NavigationController.getInstance();
+            navigationController.showLoginView();
+        });
+    }
+}

src/controller/BaseController.java

@@ -0,0 +1,41 @@
+package controller;
+
+import javax.swing.JOptionPane;
+
+public abstract class BaseController {
+
+    protected void validateNotNull(Object obj, String fieldName) {
+        if (obj == null) {
+            throw new IllegalArgumentException(fieldName + "不能为空");
+        }
+    }
+
+    protected void validateStringNotEmpty(String str, String fieldName) {
+        if (str == null || str.trim().isEmpty()) {
+            throw new IllegalArgumentException(fieldName + "不能为空");
+        }
+    }
+
+    protected void validateStringLength(String str, String fieldName, int min, int max) {
+        validateStringNotEmpty(str, fieldName);
+        if (str.length() < min || str.length() > max) {
+            throw new IllegalArgumentException(fieldName + "长度应在" + min + "-" + max + "之间");
+        }
+    }
+
+    protected void showError(String message) {
+        JOptionPane.showMessageDialog(null, message, "错误", JOptionPane.ERROR_MESSAGE);
+    }
+
+    protected void showSuccess(String message) {
+        JOptionPane.showMessageDialog(null, message, "成功", JOptionPane.INFORMATION_MESSAGE);
+    }
+
+    protected void logInfo(String message) {
+        //System.out.println("ℹ️ " + message);
+    }
+
+    protected void logError(String message) {
+        System.err.println("❌ " + message);
+    }
+}

src/controller/NavigationController.java

@@ -0,0 +1,127 @@
+package controller;
+
+import model.User;
+import view.LoginView;
+import view.RegisterView;
+import view.MainView;
+import view.ExamView;
+import view.ResultView;
+
+public class NavigationController extends BaseController implements NavigationService {
+    private static NavigationController instance;
+    private LoginView loginView;
+    private RegisterView registerView;
+    private MainView mainView;
+    private ExamView examView;
+    private ResultView resultView;
+    private User currentUser;
+
+    // 单例模式
+    public static NavigationController getInstance() {
+        if (instance == null) {
+            instance = new NavigationController();
+        }
+        return instance;
+    }
+
+    private NavigationController() {
+        // 私有构造函数
+    }
+
+    @Override
+    public void showLoginView() {
+        if (loginView == null) {
+            loginView = new LoginView();
+        }
+        loginView.setVisible(true);
+        hideAllExcept(loginView);
+        logInfo("显示登录界面");
+    }
+
+    @Override
+    public void showRegisterView() {
+        if (registerView == null) {
+            registerView = new RegisterView();
+        }
+        registerView.setVisible(true);
+        hideAllExcept(registerView);
+        logInfo("显示注册界面");
+    }
+
+    @Override
+    public void showMainView(User user) {
+        setCurrentUser(user);
+        if (mainView != null) {
+            mainView.dispose();
+        }
+        mainView = new MainView(user);
+        mainView.setVisible(true);
+        hideAllExcept(mainView);
+        logInfo("显示主界面 - 用户: " + user.getUsername());
+    }
+
+    @Override
+    public void showMainView() {
+        if (currentUser != null) {
+            showMainView(currentUser);
+        } else {
+            showLoginView();
+        }
+    }
+
+    @Override
+    public void showExamView(String difficulty, int questionCount) {
+        try {
+            validateStringNotEmpty(difficulty, "难度");
+            if (questionCount <= 0) {
+                throw new IllegalArgumentException("题目数量必须大于0");
+            }
+
+            if (examView == null) {
+                examView = new ExamView();
+            }
+            examView.startNewExam(difficulty, questionCount);
+            examView.setVisible(true);
+            hideAllExcept(examView);
+            logInfo("显示考试界面 - " + difficulty + "难度, " + questionCount + "道题");
+        } catch (Exception e) {
+            logError("显示考试界面异常: " + e.getMessage());
+            showError("无法开始考试: " + e.getMessage());
+        }
+    }
+
+    @Override
+    public void showResultView(int score, int total, double percentage) {
+        try {
+            if (resultView == null) {
+                resultView = new ResultView();
+            }
+            resultView.setResults(score, total, percentage);
+            resultView.setVisible(true);
+            hideAllExcept(resultView);
+            logInfo("显示成绩界面 - 得分: " + score + "/" + total);
+        } catch (Exception e) {
+            logError("显示成绩界面异常: " + e.getMessage());
+        }
+    }
+
+    @Override
+    public void setCurrentUser(User user) {
+        this.currentUser = user;
+        logInfo("设置当前用户: " + (user != null ? user.getUsername() : "null"));
+    }
+
+    @Override
+    public User getCurrentUser() {
+        return currentUser;
+    }
+
+    private void hideAllExcept(javax.swing.JFrame visibleFrame) {
+        javax.swing.JFrame[] frames = {loginView, registerView, mainView, examView, resultView};
+        for (javax.swing.JFrame frame : frames) {
+            if (frame != null && frame != visibleFrame) {
+                frame.setVisible(false);
+            }
+        }
+    }
+}

src/controller/NavigationService.java

@@ -0,0 +1,14 @@
+package controller;
+
+import model.User;
+
+public interface NavigationService {
+    void showLoginView();
+    void showRegisterView();
+    void showMainView(User user);
+    void showMainView();
+    void showExamView(String difficulty, int questionCount);
+    void showResultView(int score, int total, double percentage);
+    void setCurrentUser(User user);
+    User getCurrentUser();
+}

src/controller/QuestionController.java

@@ -0,0 +1,117 @@
+package controller;
+
+import model.Question;
+import model.QuestionGenerator;
+import utils.FileUtil;
+import java.util.List;
+import java.util.Arrays;
+
+public class QuestionController extends BaseController implements QuestionService {
+    private QuestionGenerator generator = new QuestionGenerator();
+    private List<Question> currentQuestions;
+    private int currentQuestionIndex = 0;
+    private int score = 0;
+    private int[] userAnswers;
+    private String currentDifficulty;
+    private int currentQuestionCount;
+
+    @Override
+    public void startNewExam(String difficulty, int questionCount) {
+        try {
+            validateStringNotEmpty(difficulty, "难度");
+            if (questionCount <= 0 || questionCount > 100) {
+                throw new IllegalArgumentException("题目数量必须在1-100之间");
+            }
+
+            currentQuestions = generator.generateQuestions(questionCount, difficulty);
+            currentQuestionIndex = 0;
+            score = 0;
+            userAnswers = new int[questionCount];
+            Arrays.fill(userAnswers, -1);
+            currentDifficulty = difficulty;
+            currentQuestionCount = questionCount;
+
+            FileUtil.saveCurrentExam(currentQuestions, difficulty, questionCount);
+            logInfo("生成新试卷: " + difficulty + " 难度, " + questionCount + " 道题");
+        } catch (Exception e) {
+            logError("开始新考试异常: " + e.getMessage());
+            throw e;
+        }
+    }
+
+    @Override
+    public String getCurrentExamInfo() {
+        if (currentDifficulty != null && currentQuestionCount > 0) {
+            return currentDifficulty + "难度 - " + currentQuestionCount + "道题";
+        }
+        return "暂无试卷";
+    }
+
+    @Override
+    public Question getCurrentQuestion() {
+        if (currentQuestions == null || currentQuestionIndex >= currentQuestions.size()) {
+            return null;
+        }
+        return currentQuestions.get(currentQuestionIndex);
+    }
+
+    @Override
+    public void submitAnswer(int answer) {
+        if (currentQuestionIndex < userAnswers.length) {
+            userAnswers[currentQuestionIndex] = answer;
+            logInfo("提交答案: 第" + getCurrentQuestionNumber() + "题, 答案: " + answer);
+        }
+    }
+
+    @Override
+    public boolean nextQuestion() {
+        currentQuestionIndex++;
+        boolean hasNext = currentQuestionIndex < currentQuestions.size();
+        logInfo("下一题: " + (hasNext ? "有" : "无"));
+        return hasNext;
+    }
+
+    @Override
+    public boolean previousQuestion() {
+        if (currentQuestionIndex > 0) {
+            currentQuestionIndex--;
+            logInfo("上一题: 第" + getCurrentQuestionNumber() + "题");
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public int calculateScore() {
+        score = 0;
+        for (int i = 0; i < currentQuestions.size(); i++) {
+            if (userAnswers[i] != -1 && currentQuestions.get(i).isCorrect(userAnswers[i])) {
+                score++;
+            }
+        }
+        logInfo("计算得分: " + score + "/" + currentQuestions.size());
+        return score;
+    }
+
+    @Override
+    public double getPercentage() {
+        double percentage = (double) score / currentQuestions.size() * 100;
+        logInfo("正确率: " + String.format("%.1f%%", percentage));
+        return percentage;
+    }
+
+    @Override
+    public int getCurrentQuestionNumber() {
+        return currentQuestionIndex + 1;
+    }
+
+    @Override
+    public int getTotalQuestions() {
+        return currentQuestions != null ? currentQuestions.size() : 0;
+    }
+
+    @Override
+    public int getUserAnswerForCurrentQuestion() {
+        return userAnswers[currentQuestionIndex];
+    }
+}

src/controller/QuestionService.java

@@ -0,0 +1,17 @@
+package controller;
+
+import model.Question;
+
+public interface QuestionService {
+    void startNewExam(String difficulty, int questionCount);
+    Question getCurrentQuestion();
+    void submitAnswer(int answer);
+    boolean nextQuestion();
+    boolean previousQuestion();
+    int calculateScore();
+    double getPercentage();
+    int getCurrentQuestionNumber();
+    int getTotalQuestions();
+    int getUserAnswerForCurrentQuestion();
+    String getCurrentExamInfo();
+}

src/controller/UserController.java

@@ -0,0 +1,156 @@
+package controller;
+
+import model.User;
+import utils.FileUtil;
+import utils.ValidationUtil;
+import utils.EmailUtil;
+
+public class UserController extends BaseController implements UserService {
+
+    @Override
+    public String registerUser(String username, String email) {
+        try {
+            validateStringLength(username, "用户名", 2, 20);
+            validateStringNotEmpty(email, "邮箱");
+
+            if (!ValidationUtil.isValidEmail(email)) {
+                return "邮箱格式不正确";
+            }
+
+            if (FileUtil.usernameExists(username)) {
+                return "用户名已被使用";
+            }
+
+            if (FileUtil.emailExists(email)) {
+                return "该邮箱已被注册";
+            }
+
+            String registrationCode = EmailUtil.generateRegistrationCode();
+            User user = new User(username, email, registrationCode);
+
+            boolean sendSuccess = EmailUtil.sendRegistrationCode(email, username, registrationCode);
+
+            if (sendSuccess) {
+                FileUtil.saveUser(user);
+                logInfo("用户注册成功: " + username);
+                return "注册码已发送到您的邮箱，请查收！";
+            } else {
+                return "邮件发送失败，请检查邮箱地址或稍后重试";
+            }
+        } catch (IllegalArgumentException e) {
+            return e.getMessage();
+        } catch (Exception e) {
+            logError("用户注册异常: " + e.getMessage());
+            return "系统错误，请稍后重试";
+        }
+    }
+
+    @Override
+    public String completeRegistration(String username, String code, String password, String confirmPassword) {
+        try {
+            validateStringNotEmpty(username, "用户名");
+            validateStringNotEmpty(code, "注册码");
+            validateStringNotEmpty(password, "密码");
+            validateStringNotEmpty(confirmPassword, "确认密码");
+
+            User user = FileUtil.loadUserByUsername(username);
+            if (user == null) {
+                return "用户不存在或注册码未发送";
+            }
+
+            if (!user.getRegistrationCode().equals(code)) {
+                return "注册码不正确";
+            }
+
+            if (!password.equals(confirmPassword)) {
+                return "两次输入的密码不一致";
+            }
+
+            if (!ValidationUtil.isValidPassword(password)) {
+                return "密码必须为6-10位，且包含大小写字母和数字";
+            }
+
+            user.setPassword(password);
+            user.setRegistered(true);
+            FileUtil.saveUser(user);
+
+            logInfo("用户完成注册: " + username);
+            return "注册成功！";
+        } catch (Exception e) {
+            logError("完成注册异常: " + e.getMessage());
+            return "系统错误，请稍后重试";
+        }
+    }
+
+    @Override
+    public User login(String loginId, String password) {
+        try {
+            validateStringNotEmpty(loginId, "登录ID");
+            validateStringNotEmpty(password, "密码");
+
+            User user;
+            if (loginId.contains("@")) {
+                user = FileUtil.loadUserByEmail(loginId);
+            } else {
+                user = FileUtil.loadUserByUsername(loginId);
+            }
+
+            if (user == null) {
+                logInfo("登录失败: 用户不存在 - " + loginId);
+                return null;
+            }
+
+            if (user.getPassword() == null || !user.getPassword().equals(password)) {
+                logInfo("登录失败: 密码错误 - " + loginId);
+                return null;
+            }
+
+            logInfo("登录成功: " + user.getUsername());
+            return user;
+        } catch (Exception e) {
+            logError("登录异常: " + e.getMessage());
+            return null;
+        }
+    }
+
+    @Override
+    public String changePassword(User user, String oldPassword, String newPassword, String confirmPassword) {
+        try {
+            validateNotNull(user, "用户");
+            validateStringNotEmpty(oldPassword, "原密码");
+            validateStringNotEmpty(newPassword, "新密码");
+            validateStringNotEmpty(confirmPassword, "确认密码");
+
+            if (!user.getPassword().equals(oldPassword)) {
+                return "原密码不正确";
+            }
+
+            if (!newPassword.equals(confirmPassword)) {
+                return "两次输入的新密码不一致";
+            }
+
+            if (!ValidationUtil.isValidPassword(newPassword)) {
+                return "新密码必须为6-10位，且包含大小写字母和数字";
+            }
+
+            user.setPassword(newPassword);
+            FileUtil.saveUser(user);
+
+            logInfo("密码修改成功: " + user.getUsername());
+            return "密码修改成功";
+        } catch (Exception e) {
+            logError("修改密码异常: " + e.getMessage());
+            return "系统错误，请稍后重试";
+        }
+    }
+
+    @Override
+    public void cleanupUnregisteredUsers() {
+        try {
+            FileUtil.cleanupUnregisteredUsers();
+            logInfo("执行未注册用户清理");
+        } catch (Exception e) {
+            logError("清理未注册用户异常: " + e.getMessage());
+        }
+    }
+}

src/controller/UserService.java

@@ -0,0 +1,11 @@
+package controller;
+
+import model.User;
+
+public interface UserService {
+    String registerUser(String username, String email);
+    String completeRegistration(String username, String code, String password, String confirmPassword);
+    User login(String loginId, String password);
+    String changePassword(User user, String oldPassword, String newPassword, String confirmPassword);
+    void cleanupUnregisteredUsers();
+}

src/model/Question.java

@@ -0,0 +1,36 @@
+package model;
+
+import java.io.Serializable;
+
+public class Question implements Serializable {
+    private static final long serialVersionUID = 1L;
+
+    private String question;
+    private String[] options;
+    private int correctAnswer;
+    private String difficulty;
+
+    public Question(String question, String[] options, int correctAnswer, String difficulty) {
+        this.question = question;
+        this.options = options;
+        this.correctAnswer = correctAnswer;
+        this.difficulty = difficulty;
+    }
+
+    // Getters
+    public String getQuestion() { return question; }
+    public String[] getOptions() { return options; }
+
+
+    public boolean isCorrect(int selectedAnswer) {
+        return selectedAnswer == correctAnswer;
+    }
+
+    @Override
+    public String toString() {
+        return "Question{" +
+                "question='" + question + '\'' +
+                ", difficulty='" + difficulty + '\'' +
+                '}';
+    }
+}

src/model/QuestionGenerator.java

@@ -0,0 +1,282 @@
+package model;
+
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Set;
+import java.util.HashSet;
+import java.util.Arrays;
+import java.util.Random;
+import java.text.DecimalFormat;
+
+public class QuestionGenerator {
+    private Random random = new Random();
+    private DecimalFormat df = new DecimalFormat("#.##"); // 保留两位小数的格式化器
+    public List<Question> generateQuestions(int count, String difficulty) {
+        List<Question> questions = new ArrayList<>();
+        Set<String> existingQuestions = new HashSet<>();
+
+        while (questions.size() < count) {
+            Question question = generateQuestion(difficulty);
+            String questionKey = question.getQuestion() + Arrays.toString(question.getOptions());
+
+            if (!existingQuestions.contains(questionKey)) {
+                questions.add(question);
+                existingQuestions.add(questionKey);
+            }
+        }
+
+        return questions;
+    }
+
+    private Question generateQuestion(String difficulty) {
+        switch (difficulty) {
+            case "小学":
+                return generatePrimaryQuestion();
+            case "初中":
+                return generateMiddleSchoolQuestion();
+            case "高中":
+                return generateHighSchoolQuestion();
+            default:
+                return generatePrimaryQuestion();
+        }
+    }
+
+    private Question generatePrimaryQuestion() {
+        int num1 = random.nextInt(50) + 1;
+        int num2 = random.nextInt(50) + 1;
+        int num3 = random.nextInt(50) + 1;
+        char[] operators = {'+', '-', '*', '/'};
+        char operator1 = operators[random.nextInt(operators.length)];
+        char operator2 = operators[random.nextInt(operators.length)];
+        String question;
+        double correctAnswer;
+        // 随机决定是否使用括号
+        if (random.nextBoolean()) {
+            // 有括号的情况
+            switch (random.nextInt(3)) {
+                case 0: // (a op b) op c
+                    correctAnswer = calculate(calculate(num1, num2, operator1), num3, operator2);
+                    question = "(" + num1 + " " + getOperatorSymbol(operator1) + " " + num2 + ") " +
+                            getOperatorSymbol(operator2) + " " + num3 + " = ?";
+                    break;
+                case 1: // a op (b op c)
+                    correctAnswer = calculate(num1, calculate(num2, num3, operator2), operator1);
+                    question = num1 + " " + getOperatorSymbol(operator1) + " (" + num2 + " " +
+                            getOperatorSymbol(operator2) + " " + num3 + ") = ?";
+                    break;
+                default: // 无括号
+                    correctAnswer = calculate(calculate(num1, num2, operator1), num3, operator2);
+                    question = num1 + " " + getOperatorSymbol(operator1) + " " + num2 + " " +
+                            getOperatorSymbol(operator2) + " " + num3 + " = ?";
+                    break;
+            }
+        } else {
+            if (operator1 == '/') {
+                num2 = random.nextInt(10) + 1; // 避免除零
+            }
+            correctAnswer = calculate(num1, num2, operator1);
+            question = num1 + " " + getOperatorSymbol(operator1) + " " + num2 + " = ?";
+        }
+        correctAnswer = Double.parseDouble(df.format(correctAnswer));
+        String[] options = generateOptions(correctAnswer);
+        return new Question(question, options, getCorrectOptionIndex(options, correctAnswer), "小学");
+    }
+
+    private Question generateMiddleSchoolQuestion() {
+        String question;
+        double correctAnswer;
+
+        if (random.nextBoolean()) {
+            // 平方或平方根题目
+            int num = random.nextInt(20) + 1;
+            if (random.nextBoolean()) {
+                correctAnswer = Math.pow(num, 2);
+                question = num + "² = ?";
+            } else {
+                int squared = num * num;
+                correctAnswer = num;
+                question = "√" + squared + " = ?";
+            }
+        } else {
+            // 带加减乘除的题目
+            int num1 = random.nextInt(50) + 1;
+            int num2 = random.nextInt(50) + 1;
+            int num3 = random.nextInt(20) + 1;
+            char[] operators = {'+', '-', '*', '/'};
+            char operator1 = operators[random.nextInt(operators.length)];
+            char operator2 = operators[random.nextInt(operators.length)];
+
+            // 随机组合平方、平方根和基本运算
+            if (random.nextBoolean()) {
+                // 平方与基本运算组合
+                correctAnswer = calculate(Math.pow(num1, 2), num2, operator1);
+                question = num1 + "² " + getOperatorSymbol(operator1) + " " + num2 + " = ?";
+            } else {
+                // 平方根与基本运算组合
+                int squared = num3 * num3;
+                correctAnswer = calculate(num3, num2, operator1);
+                question = "√" + squared + " " + getOperatorSymbol(operator1) + " " + num2 + " = ?";
+            }
+        }
+        correctAnswer = Double.parseDouble(df.format(correctAnswer));
+        String[] options = generateOptions(correctAnswer);
+        return new Question(question, options, getCorrectOptionIndex(options, correctAnswer), "初中");
+    }
+
+    private Question generateHighSchoolQuestion() {
+
+        if (random.nextBoolean()) {
+            return HighSchoolQuestionOne();
+        } else {
+            // 三角函数与基本运算组合
+           return HighSchoolQuestionTwo();
+        }
+
+    }
+
+    private  Question HighSchoolQuestionOne() {
+        String question;
+        double correctAnswer;
+        double angle = random.nextInt(360);
+        String[] trigFunctions = {"sin", "cos", "tan"};
+        String trigFunction = trigFunctions[random.nextInt(trigFunctions.length)];
+
+        switch (trigFunction) {
+            case "sin":
+                correctAnswer = Math.sin(Math.toRadians(angle));
+                question = "sin(" + angle + "°) = ?";
+                break;
+            case "cos":
+                correctAnswer = Math.cos(Math.toRadians(angle));
+                question = "cos(" + angle + "°) = ?";
+                break;
+            case "tan":
+                angle = getSafeTanAngle();
+                correctAnswer = Math.tan(Math.toRadians(angle));
+                question = "tan(" + angle + "°) = ?";
+                break;
+            default:
+                correctAnswer = 0;
+                question = "";
+        }
+        correctAnswer = Double.parseDouble(df.format(correctAnswer));
+        String[] options = generateOptions(correctAnswer);
+        return new Question(question, options, getCorrectOptionIndex(options, correctAnswer), "高中");
+    }
+    private  Question HighSchoolQuestionTwo() {
+        String question;
+        double correctAnswer;
+        double angle = random.nextInt(360);
+        int num = random.nextInt(20) + 1;
+        char[] operators = {'+', '-', '*', '/'};
+        char operator = operators[random.nextInt(operators.length)];
+        String[] trigFunctions = {"sin", "cos", "tan"};
+        String trigFunction = trigFunctions[random.nextInt(trigFunctions.length)];
+
+        double trigValue;
+        switch (trigFunction) {
+            case "sin":
+                trigValue = Math.sin(Math.toRadians(angle));
+                question = "sin(" + angle + "°) " + getOperatorSymbol(operator) + " " + num + " = ?";
+                break;
+            case "cos":
+                trigValue = Math.cos(Math.toRadians(angle));
+                question = "cos(" + angle + "°) " + getOperatorSymbol(operator) + " " + num + " = ?";
+                break;
+            case "tan":
+                angle = getSafeTanAngle();
+                trigValue = Math.tan(Math.toRadians(angle));
+                question = "tan(" + angle + "°) " + getOperatorSymbol(operator) + " " + num + " = ?";
+                break;
+            default:
+                trigValue = 0;
+                question = "";
+        }
+        trigValue = Double.parseDouble(df.format(trigValue));
+        correctAnswer = calculate(trigValue, num, operator);
+        String[] options = generateOptions(correctAnswer);
+        return new Question(question, options, getCorrectOptionIndex(options, correctAnswer), "高中");
+    }
+    // 获取安全的tan角度（更严格的范围）
+    private double getSafeTanAngle() {
+        // 为tan函数提供更安全的角度范围，避免无限大的值
+        // 排除：85°-95°, 265°-275° 等接近90°和270°的角度
+        List<Double> safeTanAngles = new ArrayList<>();
+        for (int i = 0; i < 360; i++) {
+            if (isSafeForTan(i)) {
+                safeTanAngles.add((double) i);
+            }
+        }
+        return safeTanAngles.get(random.nextInt(safeTanAngles.size()));
+    }
+    // 检查角度是否对tan函数安全（更严格的条件）
+    private boolean isSafeForTan(double angle) {
+        // 排除接近90°、270°的角度，以及排除tan值过大的角度
+        return !((angle >= 80 && angle <= 100) ||
+                (angle >= 260 && angle <= 280) ||
+                (angle >= 170 && angle <= 190) ||
+                (angle >= 350 || angle <= 10));
+    }
+
+    // 计算方法
+    private double calculate(double a, double b, char operator) {
+        switch (operator) {
+            case '+':
+                return a + b;
+            case '-':
+                return a - b;
+            case '*':
+                return a * b;
+            case '/':
+                return b != 0 ? a / b : a; // 避免除零
+            default:
+                return 0;
+        }
+    }
+
+    // 获取运算符符号
+    private String getOperatorSymbol(char operator) {
+        switch (operator) {
+            case '+':
+                return "+";
+            case '-':
+                return "-";
+            case '*':
+                return "×";
+            case '/':
+                return "÷";
+            default:
+                return "";
+        }
+    }
+
+    private String[] generateOptions(double correctAnswer) {
+        String[] options = new String[4];
+        int correctIndex = random.nextInt(4);
+
+        for (int i = 0; i < 4; i++) {
+            if (i == correctIndex) {
+                options[i] = df.format(correctAnswer);
+            } else {
+                double wrongAnswer;
+                do {
+                    double variation = (random.nextDouble() - 0.5) * 10;
+                    wrongAnswer = correctAnswer + variation;
+                    wrongAnswer = Double.parseDouble(df.format(wrongAnswer));
+                } while (Math.abs(wrongAnswer - correctAnswer) < 0.1);
+                options[i] = String.valueOf(wrongAnswer);
+            }
+        }
+
+        return options;
+    }
+
+    private int getCorrectOptionIndex(String[] options, double correctAnswer) {
+        for (int i = 0; i < options.length; i++) {
+            if (Double.parseDouble(options[i]) == correctAnswer) {
+                return i;
+            }
+        }
+        return 0;
+    }
+}

src/model/User.java

@@ -0,0 +1,30 @@
+package model;
+
+public class User {
+    private String username;    // 新增：用户名
+    private String email;
+    private String password;
+    private String registrationCode;
+    private boolean isRegistered;
+
+    public User(String username, String email, String registrationCode) {
+        this.username = username;
+        this.email = email;
+        this.registrationCode = registrationCode;
+        this.isRegistered = false;
+    }
+
+    // Getters and Setters
+    public String getUsername() { return username; }
+    public void setUsername(String username) { this.username = username; }
+
+    public String getEmail() { return email; }
+
+    public String getPassword() { return password; }
+    public void setPassword(String password) { this.password = password; }
+
+    public String getRegistrationCode() { return registrationCode; }
+
+    public boolean isRegistered() { return isRegistered; }
+    public void setRegistered(boolean registered) { isRegistered = registered; }
+}

src/utils/EmailUtil.java

@@ -0,0 +1,111 @@
+package utils;
+
+import javax.mail.Authenticator;
+import javax.mail.Message;
+import javax.mail.PasswordAuthentication;
+import javax.mail.Session;
+import javax.mail.Transport;
+import javax.mail.internet.InternetAddress;
+import javax.mail.internet.MimeMessage;
+import java.util.Properties;
+import java.util.Random;
+
+public class EmailUtil {
+    private static final Random random = new Random();
+
+    // SMTP服务器配置 - 请修改为您的邮箱配置
+    private static final String SMTP_HOST = "smtp.qq.com";        // QQ邮箱SMTP
+    private static final String SMTP_PORT = "587";                // 端口
+    private static final String FROM_EMAIL = "2536082954@qq.com"; // 发件邮箱
+    private static final String EMAIL_PASSWORD = "uihuasdsosbvdiia"; // 授权码
+    private static final String FROM_NAME = "数学学习软件";
+
+    public static String generateRegistrationCode() {
+        return String.format("%06d", random.nextInt(1000000));
+    }
+
+    /**
+     * 发送注册码到用户输入的邮箱
+     */
+    public static boolean sendRegistrationCode(String userEmail, String username, String code) {
+        // 配置邮件服务器
+        Properties props = new Properties();
+        props.put("mail.smtp.auth", "true");
+        props.put("mail.smtp.starttls.enable", "true");
+        props.put("mail.smtp.host", SMTP_HOST);
+        props.put("mail.smtp.port", SMTP_PORT);
+
+        // 超时设置
+        props.put("mail.smtp.timeout", "10000");
+        props.put("mail.smtp.connectiontimeout", "10000");
+
+        // 创建认证器
+        Authenticator authenticator = new Authenticator() {
+            @Override
+            protected PasswordAuthentication getPasswordAuthentication() {
+                return new PasswordAuthentication(FROM_EMAIL, EMAIL_PASSWORD);
+            }
+        };
+
+        Session session = Session.getInstance(props, authenticator);
+
+        try {
+            // 创建邮件
+            MimeMessage message = new MimeMessage(session);
+            message.setFrom(new InternetAddress(FROM_EMAIL, FROM_NAME, "UTF-8"));
+            message.setRecipient(Message.RecipientType.TO, new InternetAddress(userEmail));
+            message.setSubject("数学学习软件 - 注册验证码", "UTF-8");
+
+            // 邮件内容（HTML格式）
+            String htmlContent = buildEmailContent(username, code);
+            message.setContent(htmlContent, "text/html;charset=UTF-8");
+
+            // 发送邮件
+            Transport.send(message);
+            System.out.println("✅ 注册码已成功发送到: " + userEmail);
+            return true;
+
+        } catch (Exception e) {
+            System.err.println("❌ 邮件发送失败: " + e.getMessage());
+            e.printStackTrace();
+            return false;
+        }
+    }
+
+    /**
+     * 构建邮件内容
+     */
+    private static String buildEmailContent(String username, String code) {
+        return "<!DOCTYPE html>" +
+                "<html>" +
+                "<head>" +
+                "    <meta charset=\"UTF-8\">" +
+                "    <style>" +
+                "        body { font-family: Arial, sans-serif; margin: 0; padding: 20px; background-color: #f5f5f5; }" +
+                "        .container { max-width: 600px; margin: 0 auto; background: white; padding: 30px; border-radius: 10px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); }" +
+                "        .header { color: #1890ff; text-align: center; margin-bottom: 30px; }" +
+                "        .code-box { background: #f0f8ff; padding: 20px; text-align: center; margin: 25px 0; border-radius: 8px; border: 2px dashed #1890ff; }" +
+                "        .code { font-size: 32px; font-weight: bold; color: #ff4d4f; letter-spacing: 5px; }" +
+                "        .footer { margin-top: 30px; padding-top: 20px; border-top: 1px solid #eee; color: #666; font-size: 12px; }" +
+                "    </style>" +
+                "</head>" +
+                "<body>" +
+                "    <div class=\"container\">" +
+                "        <div class=\"header\">" +
+                "            <h1>数学学习软件 - 注册验证码</h1>" +
+                "        </div>" +
+                "        <p>亲爱的 <strong>" + username + "</strong>，您好！</p>" +
+                "        <p>您正在注册数学学习软件，请使用以下验证码完成注册：</p>" +
+                "        <div class=\"code-box\">" +
+                "            <div class=\"code\">" + code + "</div>" +
+                "        </div>" +
+                "        <p>如果这不是您的操作，请忽略此邮件。</p>" +
+                "        <div class=\"footer\">" +
+                "            <p>此为系统邮件，请勿回复</p>" +
+                "            <p>数学学习软件团队</p>" +
+                "        </div>" +
+                "    </div>" +
+                "</body>" +
+                "</html>";
+    }
+}

src/utils/FileUtil.java

@@ -0,0 +1,200 @@
+package utils;
+
+import model.Question;
+import model.User;
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.reflect.TypeToken;
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.lang.reflect.Type;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+public class FileUtil {
+    private static final String USERS_FILE = "data/users.json";
+    private static final String CURRENT_EXAM_FILE = "data/current_exam.json";
+    private static final Gson gson = new GsonBuilder().setPrettyPrinting().create();
+
+    static {
+        new File("data").mkdirs();
+    }
+
+    /**
+     * 清理未注册成功的用户（未设置密码的用户）
+     */
+    public static void cleanupUnregisteredUsers() {
+        try {
+            Map<String, User> users = loadAllUsers();
+            boolean hasChanges = false;
+            long currentTime = System.currentTimeMillis();
+
+            // 使用迭代器安全删除
+            Iterator<Map.Entry<String, User>> iterator = users.entrySet().iterator();
+            while (iterator.hasNext()) {
+                Map.Entry<String, User> entry = iterator.next();
+                User user = entry.getValue();
+
+                // 删除条件：未设置密码 或 未完成注册 且 创建时间超过24小时
+                if ((user.getPassword() == null || user.getPassword().isEmpty() || !user.isRegistered())) {
+                    iterator.remove();
+                    hasChanges = true;
+                    System.out.println("清理未注册用户: " + user.getUsername() + " (" + user.getEmail() + ")");
+                }
+            }
+
+            if (hasChanges) {
+                saveAllUsers(users);
+
+            } else {
+                System.out.println("没有需要清理的未注册用户");
+            }
+
+        } catch (Exception e) {
+            System.err.println("清理未注册用户时出错: " + e.getMessage());
+            e.printStackTrace();
+        }
+    }
+
+    public static void saveAllUsers(Map<String, User> users) {
+        try (FileWriter writer = new FileWriter(USERS_FILE)) {
+            gson.toJson(users, writer);
+        } catch (IOException e) {
+            System.err.println("保存用户数据失败: " + e.getMessage());
+        }
+    }
+
+    // 用户相关方法保持不变...
+    public static void saveUser(User user) {
+        try {
+            Map<String, User> users = loadAllUsers();
+            users.put(user.getUsername(), user);
+            saveAllUsers(users);
+        } catch (Exception e) {
+            System.err.println("保存用户数据失败: " + e.getMessage());
+        }
+    }
+
+    public static Map<String, User> loadAllUsers() {
+        try {
+            File file = new File(USERS_FILE);
+            if (!file.exists()) {
+                return new HashMap<>();
+            }
+
+            try (FileReader reader = new FileReader(file)) {
+                Type type = new TypeToken<Map<String, User>>(){}.getType();
+                Map<String, User> users = gson.fromJson(reader, type);
+
+                // 修复现有数据中的问题
+                if (users != null) {
+                    for (Map.Entry<String, User> entry : users.entrySet()) {
+                        User user = entry.getValue();
+                        // 确保用户名不为空
+                        if (user.getUsername() == null) {
+                            user.setUsername(entry.getKey());
+                        }
+                        // 确保密码不为null
+                        if (user.getPassword() == null) {
+                            user.setPassword("");
+                        }
+                    }
+                }
+
+                return users != null ? users : new HashMap<>();
+            }
+        } catch (IOException e) {
+            System.err.println("加载用户数据失败: " + e.getMessage());
+            return new HashMap<>();
+        }
+    }
+
+    public static User loadUserByUsername(String username) {
+        Map<String, User> users = loadAllUsers();
+        return users.get(username);
+    }
+
+    public static User loadUserByEmail(String email) {
+        Map<String, User> users = loadAllUsers();
+        for (User user : users.values()) {
+            if (user.getEmail().equals(email)) {
+                return user;
+            }
+        }
+        return null;
+    }
+
+    public static boolean usernameExists(String username) {
+        return loadAllUsers().containsKey(username);
+    }
+
+    public static boolean emailExists(String email) {
+        return loadUserByEmail(email) != null;
+    }
+
+    // ========== 试卷保存相关方法 ==========
+
+    /**
+     * 保存当前试卷到本地文件（覆盖之前的试卷）
+     */
+    public static void saveCurrentExam(List<Question> questions, String difficulty, int questionCount) {
+        try {
+            ExamData examData = new ExamData(questions, difficulty, questionCount, new Date());
+
+            try (FileWriter writer = new FileWriter(CURRENT_EXAM_FILE)) {
+                gson.toJson(examData, writer);
+            }
+            System.out.println("✅ 试卷已保存到本地: " + CURRENT_EXAM_FILE);
+
+        } catch (IOException e) {
+            System.err.println("保存试卷失败: " + e.getMessage());
+        }
+    }
+
+    /**
+     * 从本地文件加载当前试卷
+     */
+    public static ExamData loadCurrentExam() {
+        try {
+            File file = new File(CURRENT_EXAM_FILE);
+            if (!file.exists()) {
+                return null;
+            }
+
+            try (FileReader reader = new FileReader(file)) {
+                return gson.fromJson(reader, ExamData.class);
+            }
+        } catch (IOException e) {
+            System.err.println("加载试卷失败: " + e.getMessage());
+            return null;
+        }
+    }
+
+    /**
+     * 试卷数据包装类
+     */
+    public static class ExamData {
+        private List<Question> questions;
+        private String difficulty;
+        private int questionCount;
+        private Date generateTime;
+
+        public ExamData(List<Question> questions, String difficulty, int questionCount, Date generateTime) {
+            this.questions = questions;
+            this.difficulty = difficulty;
+            this.questionCount = questionCount;
+            this.generateTime = generateTime;
+        }
+
+        // Getters
+        public List<Question> getQuestions() { return questions; }
+        public String getDifficulty() { return difficulty; }
+        public int getQuestionCount() { return questionCount; }
+        public Date getGenerateTime() { return generateTime; }
+    }
+}

src/utils/ValidationUtil.java

@@ -0,0 +1,39 @@
+package utils;
+
+import java.util.regex.Pattern;
+
+public class ValidationUtil {
+
+    public static boolean isValidEmail(String email) {
+        String emailRegex = "^[A-Za-z0-9+_.-]+@(.+)$";
+        return Pattern.compile(emailRegex).matcher(email).matches();
+    }
+
+    public static boolean isValidPassword(String password) {
+        // 6-10位，必须包含大小写字母和数字
+        if (password.length() < 6 || password.length() > 10) {
+            return false;
+        }
+
+        boolean hasUpperCase = false;
+        boolean hasLowerCase = false;
+        boolean hasDigit = false;
+
+        for (char c : password.toCharArray()) {
+            if (Character.isUpperCase(c)) hasUpperCase = true;
+            if (Character.isLowerCase(c)) hasLowerCase = true;
+            if (Character.isDigit(c)) hasDigit = true;
+        }
+
+        return hasUpperCase && hasLowerCase && hasDigit;
+    }
+
+    public static boolean isNumeric(String str) {
+        try {
+            Double.parseDouble(str);
+            return true;
+        } catch (NumberFormatException e) {
+            return false;
+        }
+    }
+}

src/view/ChangePasswordDialog.java

@@ -0,0 +1,131 @@
+package view;
+
+import controller.UserController;
+import model.User;
+import utils.ValidationUtil;
+
+import javax.swing.JDialog;
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+import javax.swing.JLabel;
+import javax.swing.JPasswordField;
+import javax.swing.JButton;
+import javax.swing.BorderFactory;
+import javax.swing.JOptionPane;
+import java.awt.BorderLayout;
+import java.awt.GridLayout;
+import java.awt.Font;
+import java.awt.Color;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+public class ChangePasswordDialog extends JDialog {
+    private User currentUser;
+    private UserController userController;
+
+    private JPasswordField oldPasswordField;
+    private JPasswordField newPasswordField;
+    private JPasswordField confirmPasswordField;
+
+    public ChangePasswordDialog(JFrame parent, User user) {
+        super(parent, "修改密码", true);
+        this.currentUser = user;
+        this.userController = new UserController();
+        initializeUI();
+    }
+
+    private void initializeUI() {
+        setSize(400, 300);
+        setLocationRelativeTo(getParent());
+        setResizable(false);
+
+        JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
+        mainPanel.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
+
+        // Title
+        JLabel titleLabel = new JLabel("修改密码", JLabel.CENTER);
+        titleLabel.setFont(new Font("微软雅黑", Font.BOLD, 18));
+        mainPanel.add(titleLabel, BorderLayout.NORTH);
+
+        // Form panel
+        JPanel formPanel = new JPanel(new GridLayout(4, 2, 10, 10));
+
+        JLabel oldPasswordLabel = new JLabel("原密码:");
+        oldPasswordLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        oldPasswordField = new JPasswordField();
+
+        JLabel newPasswordLabel = new JLabel("新密码:");
+        newPasswordLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        newPasswordField = new JPasswordField();
+
+        JLabel confirmPasswordLabel = new JLabel("确认新密码:");
+        confirmPasswordLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        confirmPasswordField = new JPasswordField();
+
+        JButton confirmButton = new JButton("确认修改");
+        confirmButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        JButton cancelButton = new JButton("取消");
+        cancelButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        formPanel.add(oldPasswordLabel);
+        formPanel.add(oldPasswordField);
+        formPanel.add(newPasswordLabel);
+        formPanel.add(newPasswordField);
+        formPanel.add(confirmPasswordLabel);
+        formPanel.add(confirmPasswordField);
+        formPanel.add(confirmButton);
+        formPanel.add(cancelButton);
+
+        mainPanel.add(formPanel, BorderLayout.CENTER);
+
+        // 密码要求提示
+        JLabel hintLabel = new JLabel(
+                "<html><body style='text-align: center'>" +
+                        "密码要求：6-10位，必须包含大小写字母和数字<br>" +
+                        "例如：Abc123、Test456" +
+                        "</body></html>", JLabel.CENTER);
+        hintLabel.setFont(new Font("微软雅黑", Font.PLAIN, 12));
+        hintLabel.setForeground(Color.GRAY);
+        mainPanel.add(hintLabel, BorderLayout.SOUTH);
+
+        // Add action listeners
+        confirmButton.addActionListener(new ConfirmAction());
+        cancelButton.addActionListener(e -> dispose());
+
+        // Enter key support
+        oldPasswordField.addActionListener(new ConfirmAction());
+        newPasswordField.addActionListener(new ConfirmAction());
+        confirmPasswordField.addActionListener(new ConfirmAction());
+
+        add(mainPanel);
+    }
+
+    private class ConfirmAction implements ActionListener {
+        @Override
+        public void actionPerformed(ActionEvent e) {
+            String oldPassword = new String(oldPasswordField.getPassword());
+            String newPassword = new String(newPasswordField.getPassword());
+            String confirmPassword = new String(confirmPasswordField.getPassword());
+
+            // 验证输入
+            if (oldPassword.isEmpty() || newPassword.isEmpty() || confirmPassword.isEmpty()) {
+                JOptionPane.showMessageDialog(ChangePasswordDialog.this,
+                        "请填写所有密码字段", "错误", JOptionPane.ERROR_MESSAGE);
+                return;
+            }
+
+            // 调用控制器修改密码
+            String result = userController.changePassword(currentUser, oldPassword, newPassword, confirmPassword);
+
+            if (result.equals("密码修改成功")) {
+                JOptionPane.showMessageDialog(ChangePasswordDialog.this,
+                        "密码修改成功！", "成功", JOptionPane.INFORMATION_MESSAGE);
+                dispose(); // 关闭对话框
+            } else {
+                JOptionPane.showMessageDialog(ChangePasswordDialog.this,
+                        result, "错误", JOptionPane.ERROR_MESSAGE);
+            }
+        }
+    }
+}

src/view/ExamView.java

@@ -0,0 +1,281 @@
+package view;
+
+import controller.NavigationController;
+import controller.NavigationService;
+import controller.QuestionController;
+import model.Question;
+
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+import javax.swing.JLabel;
+import javax.swing.JRadioButton;
+import javax.swing.JButton;
+import javax.swing.ButtonGroup;
+import javax.swing.BorderFactory;
+import javax.swing.JOptionPane;
+import java.awt.BorderLayout;
+import java.awt.GridLayout;
+import java.awt.FlowLayout;
+import java.awt.Font;
+import java.awt.Color;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.awt.event.ItemEvent;
+import java.awt.event.ItemListener;
+
+public class ExamView extends JFrame {
+    private QuestionController questionController;
+    private NavigationService navigationService;
+    private JLabel questionLabel;
+    private JLabel progressLabel;
+    private ButtonGroup optionGroup;
+    private JRadioButton[] optionButtons;
+    private JButton prevButton;
+    private JButton nextButton;
+    private JButton submitButton;
+    private JLabel hintLabel;
+
+    public ExamView() {
+        questionController = new QuestionController();
+        navigationService = NavigationController.getInstance();
+        initializeUI();
+    }
+
+    private void initializeUI() {
+        setTitle("数学学习软件 - 答题界面");
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setSize(600, 450);
+        setLocationRelativeTo(null);
+        setResizable(false);
+
+        JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
+        mainPanel.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
+
+        // Progress label
+        progressLabel = new JLabel("", JLabel.CENTER);
+        progressLabel.setFont(new Font("微软雅黑", Font.BOLD, 16));
+        mainPanel.add(progressLabel, BorderLayout.NORTH);
+
+        // Question panel
+        JPanel questionPanel = new JPanel(new BorderLayout(10, 10));
+        questionLabel = new JLabel("", JLabel.CENTER);
+        questionLabel.setFont(new Font("微软雅黑", Font.PLAIN, 18));
+        questionPanel.add(questionLabel, BorderLayout.NORTH);
+
+        // Options panel
+        JPanel optionsPanel = new JPanel(new GridLayout(4, 1, 10, 10));
+        optionGroup = new ButtonGroup();
+        optionButtons = new JRadioButton[4];
+
+        for (int i = 0; i < 4; i++) {
+            optionButtons[i] = new JRadioButton();
+            optionButtons[i].setFont(new Font("微软雅黑", Font.PLAIN, 14));
+            optionGroup.add(optionButtons[i]);
+            optionsPanel.add(optionButtons[i]);
+
+            optionButtons[i].addItemListener(new OptionSelectionListener());
+        }
+
+        questionPanel.add(optionsPanel, BorderLayout.CENTER);
+        mainPanel.add(questionPanel, BorderLayout.CENTER);
+
+        // Hint label
+        hintLabel = new JLabel("请选择答案后继续", JLabel.CENTER);
+        hintLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        hintLabel.setForeground(Color.RED);
+        hintLabel.setVisible(false);
+        mainPanel.add(hintLabel, BorderLayout.SOUTH);
+
+        // Button panel
+        JPanel buttonPanel = new JPanel(new FlowLayout());
+        prevButton = new JButton("上一题");
+        nextButton = new JButton("下一题");
+        submitButton = new JButton("提交试卷");
+
+        prevButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        nextButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        submitButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        nextButton.setEnabled(false);
+
+        buttonPanel.add(prevButton);
+        buttonPanel.add(nextButton);
+        buttonPanel.add(submitButton);
+
+        mainPanel.add(buttonPanel, BorderLayout.SOUTH);
+
+        // Add action listeners
+        prevButton.addActionListener(new PrevButtonAction());
+        nextButton.addActionListener(new NextButtonAction());
+        submitButton.addActionListener(new SubmitButtonAction());
+
+        add(mainPanel);
+    }
+
+    public void startNewExam(String difficulty, int questionCount) {
+        questionController.startNewExam(difficulty, questionCount);
+        displayCurrentQuestion();
+        updateNavigationButtons();
+        updateNextButtonState();
+    }
+
+    private void displayCurrentQuestion() {
+        Question question = questionController.getCurrentQuestion();
+        if (question == null) return;
+
+        progressLabel.setText(String.format("第 %d 题 / 共 %d 题",
+                questionController.getCurrentQuestionNumber(),
+                questionController.getTotalQuestions()));
+
+        questionLabel.setText(question.getQuestion());
+
+        String[] options = question.getOptions();
+        for (int i = 0; i < 4; i++) {
+            optionButtons[i].setText((char)('A' + i) + ". " + options[i]);
+        }
+
+        // Restore user's previous selection
+        int userAnswer = questionController.getUserAnswerForCurrentQuestion();
+        optionGroup.clearSelection();
+        if (userAnswer != -1) {
+            optionButtons[userAnswer].setSelected(true);
+            nextButton.setEnabled(canGoNext());
+            hintLabel.setVisible(false);
+        } else {
+            nextButton.setEnabled(false);
+        }
+    }
+
+    private void updateNavigationButtons() {
+        int current = questionController.getCurrentQuestionNumber();
+        int total = questionController.getTotalQuestions();
+
+        prevButton.setEnabled(current > 1);
+
+        // 修改这里：最后一题时禁用下一题按钮
+        boolean isLastQuestion = current == total;
+        nextButton.setEnabled(!isLastQuestion && isCurrentQuestionAnswered());
+        submitButton.setEnabled(isLastQuestion && isCurrentQuestionAnswered());
+    }
+
+    private void updateNextButtonState() {
+        boolean isLastQuestion = questionController.getCurrentQuestionNumber() == questionController.getTotalQuestions();
+
+        if (isLastQuestion) {
+            // 最后一题：禁用下一题，启用提交按钮（如果已回答）
+            nextButton.setEnabled(false);
+            submitButton.setEnabled(isCurrentQuestionAnswered());
+        } else {
+            // 不是最后一题：根据是否回答控制下一题按钮
+            nextButton.setEnabled(isCurrentQuestionAnswered());
+            submitButton.setEnabled(false);
+        }
+
+        hintLabel.setVisible(!isCurrentQuestionAnswered());
+    }
+
+    private boolean canGoNext() {
+        int current = questionController.getCurrentQuestionNumber();
+        int total = questionController.getTotalQuestions();
+        return current < total && isCurrentQuestionAnswered();
+    }
+
+    private boolean isCurrentQuestionAnswered() {
+        for (int i = 0; i < 4; i++) {
+            if (optionButtons[i].isSelected()) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private void saveCurrentAnswer() {
+        for (int i = 0; i < 4; i++) {
+            if (optionButtons[i].isSelected()) {
+                questionController.submitAnswer(i);
+                break;
+            }
+        }
+    }
+
+    // 选项选择监听器
+    private class OptionSelectionListener implements ItemListener {
+        @Override
+        public void itemStateChanged(ItemEvent e) {
+            if (e.getStateChange() == ItemEvent.SELECTED) {
+                saveCurrentAnswer(); // 立即保存答案
+                updateNextButtonState();
+                updateNavigationButtons();
+            }
+        }
+    }
+
+    private class PrevButtonAction implements ActionListener {
+        @Override
+        public void actionPerformed(ActionEvent e) {
+            saveCurrentAnswer();
+            if (questionController.previousQuestion()) {
+                displayCurrentQuestion();
+                updateNavigationButtons();
+                updateNextButtonState();
+            }
+        }
+    }
+
+    private class NextButtonAction implements ActionListener {
+        @Override
+        public void actionPerformed(ActionEvent e) {
+            int current = questionController.getCurrentQuestionNumber();
+            int total = questionController.getTotalQuestions();
+
+            // 检查是否是最后一题
+            if (current >= total) {
+                JOptionPane.showMessageDialog(ExamView.this,
+                        "已经是最后一题了，请点击提交试卷！", "提示",
+                        JOptionPane.INFORMATION_MESSAGE);
+                return;
+            }
+
+            if (!isCurrentQuestionAnswered()) {
+                JOptionPane.showMessageDialog(ExamView.this,
+                        "请先选择答案！", "提示", JOptionPane.WARNING_MESSAGE);
+                return;
+            }
+
+            saveCurrentAnswer();
+            if (questionController.nextQuestion()) {
+                displayCurrentQuestion();
+                updateNavigationButtons();
+                updateNextButtonState();
+            } else {
+                // 如果无法切换到下一题，可能是最后一题
+                JOptionPane.showMessageDialog(ExamView.this,
+                        "无法切换到下一题，请点击提交试卷！", "提示",
+                        JOptionPane.INFORMATION_MESSAGE);
+            }
+        }
+    }
+
+    private class SubmitButtonAction implements ActionListener {
+        @Override
+        public void actionPerformed(ActionEvent e) {
+            if (!isCurrentQuestionAnswered()) {
+                JOptionPane.showMessageDialog(ExamView.this,
+                        "请先完成本题！", "提示", JOptionPane.WARNING_MESSAGE);
+                return;
+            }
+
+            saveCurrentAnswer();
+
+            int score = questionController.calculateScore();
+            int total = questionController.getTotalQuestions();
+            double percentage = questionController.getPercentage();
+
+            // 关闭当前窗口
+            dispose();
+
+            // 显示结果页面
+            navigationService.showResultView(score, total, percentage);  // 修改
+        }
+    }
+}

src/view/LoginView.java

@@ -0,0 +1,130 @@
+package view;
+
+import controller.NavigationController;
+import controller.NavigationService;
+import controller.UserController;
+import controller.UserService;
+import model.User;
+
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+import javax.swing.JLabel;
+import javax.swing.JTextField;
+import javax.swing.JPasswordField;
+import javax.swing.JButton;
+import javax.swing.BorderFactory;
+import javax.swing.JOptionPane;
+import java.awt.BorderLayout;
+import java.awt.GridLayout;
+import java.awt.FlowLayout;
+import java.awt.Font;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+public class LoginView extends JFrame {
+    private JTextField usernameField;
+    private JPasswordField passwordField;
+    private UserService userController;
+    private NavigationService navigationService;
+
+    public LoginView() {
+        userController = new UserController();
+        navigationService = NavigationController.getInstance();
+        initializeUI();
+        cleanupUnregisteredUsers();
+    }
+
+    private void cleanupUnregisteredUsers() {
+        try {
+            userController.cleanupUnregisteredUsers();
+        } catch (Exception e) {
+            System.err.println("清理未注册用户时出错: " + e.getMessage());
+        }
+    }
+
+    private void initializeUI() {
+        setTitle("数学学习软件 - 登录");
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setSize(400, 300);
+        setLocationRelativeTo(null);
+        setResizable(false);
+
+        JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
+        mainPanel.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
+
+        // Title
+        JLabel titleLabel = new JLabel("用户登录", JLabel.CENTER);
+        titleLabel.setFont(new Font("微软雅黑", Font.BOLD, 24));
+        mainPanel.add(titleLabel, BorderLayout.NORTH);
+
+        // Form panel
+        JPanel formPanel = new JPanel(new GridLayout(3, 2, 10, 10));
+
+        JLabel usernameLabel = new JLabel("用户名:");
+        usernameLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        usernameField = new JTextField();
+
+        JLabel passwordLabel = new JLabel("密码:");
+        passwordLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        passwordField = new JPasswordField();
+
+        formPanel.add(usernameLabel);
+        formPanel.add(usernameField);
+        formPanel.add(passwordLabel);
+        formPanel.add(passwordField);
+
+        // Buttons
+        JPanel buttonPanel = new JPanel(new FlowLayout());
+        JButton loginButton = new JButton("登录");
+        JButton registerButton = new JButton("注册");
+
+        loginButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        registerButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        buttonPanel.add(loginButton);
+        buttonPanel.add(registerButton);
+
+        formPanel.add(new JLabel()); // Empty cell
+        formPanel.add(buttonPanel);
+
+        mainPanel.add(formPanel, BorderLayout.CENTER);
+
+        // Add action listeners
+        loginButton.addActionListener(new LoginAction());
+        registerButton.addActionListener(e -> {
+
+            navigationService.showRegisterView();
+        });
+
+        // Enter key support
+        usernameField.addActionListener(new LoginAction());
+        passwordField.addActionListener(new LoginAction());
+
+        add(mainPanel);
+    }
+
+    private class LoginAction implements ActionListener {
+        @Override
+        public void actionPerformed(ActionEvent e) {
+            String username = usernameField.getText().trim();
+            String password = new String(passwordField.getPassword());
+
+            if (username.isEmpty() || password.isEmpty()) {
+                JOptionPane.showMessageDialog(LoginView.this,
+                        "请输入用户名和密码", "错误", JOptionPane.ERROR_MESSAGE);
+                return;
+            }
+
+            User user = userController.login(username, password);
+            if (user != null) {
+                JOptionPane.showMessageDialog(LoginView.this,
+                        "登录成功！", "成功", JOptionPane.INFORMATION_MESSAGE);
+
+                navigationService.showMainView(user);
+            } else {
+                JOptionPane.showMessageDialog(LoginView.this,
+                        "用户名或密码错误", "错误", JOptionPane.ERROR_MESSAGE);
+            }
+        }
+    }
+}

src/view/MainView.java

@@ -0,0 +1,126 @@
+package view;
+
+import controller.NavigationController;
+import controller.NavigationService;
+import controller.UserController;
+import model.User;
+
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+import javax.swing.JLabel;
+import javax.swing.JComboBox;
+import javax.swing.JTextField;
+import javax.swing.JButton;
+import javax.swing.BorderFactory;
+import javax.swing.JOptionPane;
+import java.awt.BorderLayout;
+import java.awt.GridLayout;
+import java.awt.FlowLayout;
+import java.awt.Font;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+public class MainView extends JFrame {
+    private JComboBox<String> difficultyComboBox;
+    private JTextField countField;
+    private User currentUser; // 保存当前登录用户
+    private NavigationService navigationService;
+
+    public MainView(User user) {
+        this.currentUser = user;
+        this.navigationService = NavigationController.getInstance();
+        initializeUI();
+    }
+
+    private void initializeUI() {
+        setTitle("数学学习软件 - 主界面");
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setSize(450, 350);
+        setLocationRelativeTo(null);
+        setResizable(false);
+
+        JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
+        mainPanel.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
+
+        // Title - 显示欢迎信息
+        JLabel titleLabel = new JLabel("欢迎 " + currentUser.getUsername() + "！", JLabel.CENTER);
+        titleLabel.setFont(new Font("微软雅黑", Font.BOLD, 24));
+        mainPanel.add(titleLabel, BorderLayout.NORTH);
+
+        // Form panel
+        JPanel formPanel = new JPanel(new GridLayout(3, 2, 10, 10));
+
+        JLabel difficultyLabel = new JLabel("难度级别:");
+        difficultyLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        String[] difficulties = {"小学", "初中", "高中"};
+        difficultyComboBox = new JComboBox<>(difficulties);
+        difficultyComboBox.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        JLabel countLabel = new JLabel("题目数量:");
+        countLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        countField = new JTextField("10");
+        countField.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        JButton startButton = new JButton("开始答题");
+        startButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        formPanel.add(difficultyLabel);
+        formPanel.add(difficultyComboBox);
+        formPanel.add(countLabel);
+        formPanel.add(countField);
+        formPanel.add(new JLabel()); // Empty cell
+        formPanel.add(startButton);
+
+        mainPanel.add(formPanel, BorderLayout.CENTER);
+
+
+        JPanel buttonPanel = new JPanel(new FlowLayout());
+        JButton changePasswordButton = new JButton("修改密码");
+        JButton logoutButton = new JButton("退出登录");
+
+        changePasswordButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        logoutButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        buttonPanel.add(changePasswordButton);
+        buttonPanel.add(logoutButton);
+
+        mainPanel.add(buttonPanel, BorderLayout.SOUTH);
+
+        // Add action listeners
+        startButton.addActionListener(new StartExamAction());
+        changePasswordButton.addActionListener(new ChangePasswordAction());
+        logoutButton.addActionListener(e -> navigationService.showLoginView());  // 修改
+
+        add(mainPanel);
+    }
+
+    private class StartExamAction implements ActionListener {
+        @Override
+        public void actionPerformed(ActionEvent e) {
+            String difficulty = (String) difficultyComboBox.getSelectedItem();
+            String countText = countField.getText().trim();
+
+            try {
+                int count = Integer.parseInt(countText);
+                if (count < 10 || count > 30) {
+                    JOptionPane.showMessageDialog(MainView.this,
+                            "题目数量必须在10-30之间", "错误", JOptionPane.ERROR_MESSAGE);
+                    return;
+                }
+
+                navigationService.showExamView(difficulty, count);  // 修改
+            } catch (NumberFormatException ex) {
+                JOptionPane.showMessageDialog(MainView.this,
+                        "请输入有效的数字", "错误", JOptionPane.ERROR_MESSAGE);
+            }
+        }
+    }
+
+    private class ChangePasswordAction implements ActionListener {
+        @Override
+        public void actionPerformed(ActionEvent e) {
+            // 打开修改密码对话框
+            new ChangePasswordDialog(MainView.this, currentUser).setVisible(true);
+        }
+    }
+}

src/view/RegisterView.java

@@ -0,0 +1,164 @@
+package view;
+
+import controller.NavigationController;
+import controller.NavigationService;
+import controller.UserController;
+import model.User;
+
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+import javax.swing.JLabel;
+import javax.swing.JTextField;
+import javax.swing.JPasswordField;
+import javax.swing.JButton;
+import javax.swing.BorderFactory;
+import javax.swing.JOptionPane;
+import java.awt.BorderLayout;
+import java.awt.GridLayout;
+import java.awt.FlowLayout;
+import java.awt.Font;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+public class RegisterView extends JFrame {
+    private JTextField usernameField;    // 用户名输入框
+    private JTextField emailField;
+    private JTextField codeField;
+    private JPasswordField passwordField;
+    private JPasswordField confirmPasswordField;
+    private UserController userController;
+    private NavigationService navigationService;  // 新增
+    private String currentUsername;      // 保存当前注册的用户名
+
+    public RegisterView() {
+        userController = new UserController();
+        navigationService = NavigationController.getInstance();  // 新增
+        initializeUI();
+    }
+
+    private void initializeUI() {
+        setTitle("数学学习软件 - 注册");
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setSize(550, 500);
+        setLocationRelativeTo(null);
+        setResizable(false);
+
+        JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
+        mainPanel.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
+
+        // Title
+        JLabel titleLabel = new JLabel("用户注册", JLabel.CENTER);
+        titleLabel.setFont(new Font("微软雅黑", Font.BOLD, 24));
+        mainPanel.add(titleLabel, BorderLayout.NORTH);
+
+        // Form panel - 增加用户名字段
+        JPanel formPanel = new JPanel(new GridLayout(8, 2, 10, 10));
+
+        JLabel usernameLabel = new JLabel("用户名:");
+        usernameLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        usernameField = new JTextField();
+
+        JLabel emailLabel = new JLabel("邮箱:");
+        emailLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        emailField = new JTextField();
+
+        JLabel codeLabel = new JLabel("注册码:");
+        codeLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        codeField = new JTextField();
+
+        JLabel passwordLabel = new JLabel("密码:");
+        passwordLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        passwordField = new JPasswordField();
+
+        JLabel confirmPasswordLabel = new JLabel("确认密码:");
+        confirmPasswordLabel.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        confirmPasswordField = new JPasswordField();
+
+        JButton sendCodeButton = new JButton("发送注册码");
+        sendCodeButton.setFont(new Font("微软雅黑", Font.PLAIN, 12));
+
+        JButton registerButton = new JButton("完成注册");
+        registerButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        // 布局表单
+        formPanel.add(usernameLabel);
+        formPanel.add(usernameField);
+        formPanel.add(emailLabel);
+        formPanel.add(emailField);
+        formPanel.add(sendCodeButton);
+        formPanel.add(new JLabel());
+        formPanel.add(codeLabel);
+        formPanel.add(codeField);
+        formPanel.add(passwordLabel);
+        formPanel.add(passwordField);
+        formPanel.add(confirmPasswordLabel);
+        formPanel.add(confirmPasswordField);
+
+        formPanel.add(registerButton);
+
+        mainPanel.add(formPanel, BorderLayout.CENTER);
+
+        // Back button
+        JButton backButton = new JButton("返回登录");
+        backButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        backButton.addActionListener(e -> navigationService.showLoginView());  // 修改
+
+        JPanel bottomPanel = new JPanel(new FlowLayout());
+        bottomPanel.add(backButton);
+        mainPanel.add(bottomPanel, BorderLayout.SOUTH);
+
+        // Add action listeners
+        sendCodeButton.addActionListener(new SendCodeAction());
+        registerButton.addActionListener(new RegisterAction());
+
+        add(mainPanel);
+    }
+
+    private class SendCodeAction implements ActionListener {
+        @Override
+        public void actionPerformed(ActionEvent e) {
+            String username = usernameField.getText().trim();
+            String email = emailField.getText().trim();
+
+            if (username.isEmpty() || email.isEmpty()) {
+                JOptionPane.showMessageDialog(RegisterView.this,
+                        "请输入用户名和邮箱", "错误", JOptionPane.ERROR_MESSAGE);
+                return;
+            }
+
+            String result = userController.registerUser(username, email);
+            JOptionPane.showMessageDialog(RegisterView.this, result);
+
+            if (result.contains("发送")) {
+                currentUsername = username;
+            }
+        }
+    }
+
+    private class RegisterAction implements ActionListener {
+        @Override
+        public void actionPerformed(ActionEvent e) {
+            String username = usernameField.getText().trim();
+            String code = codeField.getText().trim();
+            String password = new String(passwordField.getPassword());
+            String confirmPassword = new String(confirmPasswordField.getPassword());
+
+            if (username.isEmpty() || code.isEmpty() || password.isEmpty() || confirmPassword.isEmpty()) {
+                JOptionPane.showMessageDialog(RegisterView.this,
+                        "请填写所有字段", "错误", JOptionPane.ERROR_MESSAGE);
+                return;
+            }
+
+            String result = userController.completeRegistration(username, code, password, confirmPassword);
+
+            if (result.equals("注册成功！")) {
+                JOptionPane.showMessageDialog(RegisterView.this,
+                        result, "成功", JOptionPane.INFORMATION_MESSAGE);
+                navigationService.showLoginView();  // 修改
+            } else {
+                JOptionPane.showMessageDialog(RegisterView.this,
+                        result, "错误", JOptionPane.ERROR_MESSAGE);
+            }
+        }
+    }
+}

src/view/ResultView.java

@@ -0,0 +1,79 @@
+package view;
+
+import controller.NavigationController;
+import controller.NavigationService;
+
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+import javax.swing.JLabel;
+import javax.swing.JButton;
+import javax.swing.BorderFactory;
+import java.awt.BorderLayout;
+import java.awt.GridLayout;
+import java.awt.FlowLayout;
+import java.awt.Font;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+public class ResultView extends JFrame {
+    private JLabel scoreLabel;
+    private JLabel percentageLabel;
+    private NavigationService navigationService;
+
+    public ResultView() {
+        navigationService = NavigationController.getInstance();  // 新增
+        initializeUI();
+    }
+
+    private void initializeUI() {
+        setTitle("数学学习软件 - 成绩界面");
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setSize(400, 300);
+        setLocationRelativeTo(null);
+        setResizable(false);
+
+        JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
+        mainPanel.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
+
+        // Title
+        JLabel titleLabel = new JLabel("考试结果", JLabel.CENTER);
+        titleLabel.setFont(new Font("微软雅黑", Font.BOLD, 24));
+        mainPanel.add(titleLabel, BorderLayout.NORTH);
+
+        // Result panel
+        JPanel resultPanel = new JPanel(new GridLayout(2, 1, 10, 10));
+
+        scoreLabel = new JLabel("", JLabel.CENTER);
+        scoreLabel.setFont(new Font("微软雅黑", Font.PLAIN, 18));
+
+        percentageLabel = new JLabel("", JLabel.CENTER);
+        percentageLabel.setFont(new Font("微软雅黑", Font.PLAIN, 18));
+
+        resultPanel.add(scoreLabel);
+        resultPanel.add(percentageLabel);
+        mainPanel.add(resultPanel, BorderLayout.CENTER);
+
+        // Button panel
+        JPanel buttonPanel = new JPanel(new FlowLayout());
+        JButton continueButton = new JButton("继续做题");
+        JButton exitButton = new JButton("退出系统");
+
+        continueButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+        exitButton.setFont(new Font("微软雅黑", Font.PLAIN, 14));
+
+        buttonPanel.add(continueButton);
+        buttonPanel.add(exitButton);
+        mainPanel.add(buttonPanel, BorderLayout.SOUTH);
+
+        // Add action listeners
+        continueButton.addActionListener(e -> navigationService.showMainView());  // 修改
+        exitButton.addActionListener(e -> System.exit(0));
+
+        add(mainPanel);
+    }
+
+    public void setResults(int score, int total, double percentage) {
+        scoreLabel.setText(String.format("得分: %d / %d", score, total));
+        percentageLabel.setText(String.format("正确率: %.1f%%", percentage));
+    }
+}