初步框架

pom.xml

@@ -1,17 +1,81 @@
-<?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
-    <groupId>org.example</groupId>
+    <groupId>com.mathapp</groupId>
     <artifactId>TestSystem</artifactId>
-    <version>1.0-SNAPSHOT</version>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+
+    <name>Math Learning App</name>
+    <description>A desktop application for learning math for elementary, middle, and high school students.</description>
 
     <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>22</maven.compiler.source>
         <maven.compiler.target>22</maven.compiler.target>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
 
+    <dependencies>
+        <!-- 现代化Swing UI外观库 -->
+        <dependency>
+            <groupId>com.formdev</groupId>
+            <artifactId>flatlaf</artifactId>
+            <version>3.4.1</version>
+        </dependency>
+
+        <!-- 邮件发送功能库 -->
+        <dependency>
+            <groupId>com.sun.mail</groupId>
+            <artifactId>jakarta.mail</artifactId>
+            <version>2.0.1</version>
+        </dependency>
+
+        <!-- 数学表达式求值库 -->
+        <dependency>
+            <groupId>net.objecthunter</groupId>
+            <artifactId>exp4j</artifactId>
+            <version>0.4.8</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <source>22</source>
+                    <target>22</target>
+                </configuration>
+            </plugin>
+            <!-- 打包为可执行JAR文件的插件 -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <version>3.6.0</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <mainClass>com.mathapp.MathApp</mainClass>
+                        </manifest>
+                    </archive>
+                    <descriptorRefs>
+                        <descriptorRef>jar-with-dependencies</descriptorRef>
+                    </descriptorRefs>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>make-assembly</id>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
 </project>

src/main/java/com/mathapp/MathApp.java

@@ -0,0 +1,118 @@
+package com.mathapp;
+
+import com.formdev.flatlaf.FlatLightLaf;
+import com.mathapp.models.TestPaper;
+import com.mathapp.panels.*;
+
+import javax.swing.*;
+import java.awt.*;
+
+/**
+ * 应用程序主类
+ * 负责初始化UI、管理面板切换和维护全局状态。
+ */
+public class MathApp extends JFrame {
+
+  private CardLayout cardLayout;
+  private JPanel mainPanel;
+  private String currentUserEmail;
+
+  public static final String LOGIN_PANEL = "LoginPanel";
+  public static final String REGISTER_PANEL = "RegisterPanel";
+  public static final String SET_PASSWORD_PANEL = "SetPasswordPanel";
+  public static final String MAIN_MENU_PANEL = "MainMenuPanel";
+  public static final String QUIZ_PANEL = "QuizPanel";
+  public static final String RESULTS_PANEL = "ResultsPanel";
+  public static final String CHANGE_PASSWORD_PANEL = "ChangePasswordPanel";
+
+  public MathApp() {
+    initUI();
+  }
+
+  private void initUI() {
+    setTitle("数学学习平台");
+    setSize(800, 600);
+    setResizable(false);
+    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+    setLocationRelativeTo(null);
+
+    cardLayout = new CardLayout();
+    mainPanel = new JPanel(cardLayout);
+
+    // 添加所有静态面板
+    mainPanel.add(new LoginPanel(this), LOGIN_PANEL);
+    mainPanel.add(new RegisterPanel(this), REGISTER_PANEL);
+    mainPanel.add(new MainMenuPanel(this), MAIN_MENU_PANEL);
+    mainPanel.add(new ChangePasswordPanel(this), CHANGE_PASSWORD_PANEL);
+
+    add(mainPanel);
+  }
+
+  /**
+   * 切换到指定的面板
+   * @param panelName 要显示的面板名称
+   */
+  public void showPanel(String panelName) {
+    cardLayout.show(mainPanel, panelName);
+  }
+
+  /**
+   * 注册成功后，动态创建并跳转到设置密码面板
+   * @param email 刚刚注册成功的用户邮箱
+   */
+  public void showSetPasswordPanel(String email) {
+    this.currentUserEmail = email; // 临时存储
+    SetPasswordPanel setPasswordPanel = new SetPasswordPanel(this, email);
+    mainPanel.add(setPasswordPanel, SET_PASSWORD_PANEL);
+    showPanel(SET_PASSWORD_PANEL);
+  }
+
+  /**
+   * 开始一场新的测验
+   * @param level "小学", "初中", 或 "高中"
+   * @param questionCount 题目数量
+   */
+  public void startQuiz(String level, int questionCount) {
+    QuizPanel quizPanel = new QuizPanel(this, level, questionCount);
+    mainPanel.add(quizPanel, QUIZ_PANEL);
+    showPanel(QUIZ_PANEL);
+  }
+
+  /**
+   * 显示测验结果
+   * @param score 用户得分
+   * @param totalQuestions 题目总数
+   * @param testPaper 完整的试卷数据，用于保存
+   */
+  public void showResults(int score, int totalQuestions, TestPaper testPaper) {
+    ResultsPanel resultsPanel = new ResultsPanel(this, score, totalQuestions);
+    mainPanel.add(resultsPanel, RESULTS_PANEL);
+    showPanel(RESULTS_PANEL);
+  }
+
+  public void setCurrentUserEmail(String email) {
+    this.currentUserEmail = email;
+  }
+
+  public String getCurrentUserEmail() {
+    return currentUserEmail;
+  }
+
+
+  public static void main(String[] args) {
+    // 设置现代化UI外观
+    FlatLightLaf.setup();
+    // 全局UI定制
+    UIManager.put("Button.arc", 999);
+    UIManager.put("Component.arc", 15);
+    UIManager.put("ProgressBar.arc", 999);
+    UIManager.put("TextComponent.arc", 15);
+    UIManager.put("OptionPane.buttonAreaBorder", BorderFactory.createEmptyBorder(10, 0, 0, 0));
+
+
+    EventQueue.invokeLater(() -> {
+      MathApp ex = new MathApp();
+      ex.setVisible(true);
+    });
+  }
+}

src/main/java/com/mathapp/controllers/QuizController.java

@@ -0,0 +1,88 @@
+package com.mathapp.controllers;
+
+import com.mathapp.MathApp;
+import com.mathapp.models.Question;
+import com.mathapp.models.TestPaper;
+import com.mathapp.panels.QuizPanel;
+import com.mathapp.services.DataPersistence;
+import com.mathapp.services.QuestionGenerator;
+
+import javax.swing.*;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+
+public class QuizController {
+  private final MathApp app;
+  private final String level;
+  private final int questionCount;
+  private QuizPanel quizPanel;
+  private List<Question> questions;
+  private final List<String> userAnswers;
+  private int currentQuestionIndex;
+  private int score;
+
+  public QuizController(MathApp app, String level, int questionCount) {
+    this.app = app;
+    this.level = level;
+    this.questionCount = questionCount;
+    this.userAnswers = new ArrayList<>();
+    this.currentQuestionIndex = 0;
+    this.score = 0;
+  }
+
+  public void startQuiz(QuizPanel panel) {
+    this.quizPanel = panel;
+    // 在后台线程生成题目
+    SwingWorker<List<Question>, Void> worker = new SwingWorker<>() {
+      @Override
+      protected List<Question> doInBackground() throws Exception {
+        return QuestionGenerator.generateQuestions(level, questionCount);
+      }
+
+      @Override
+      protected void done() {
+        try {
+          questions = get();
+          if (questions.isEmpty()) {
+            JOptionPane.showMessageDialog(quizPanel, "题目生成失败，请重试。", "错误", JOptionPane.ERROR_MESSAGE);
+            app.showPanel(MathApp.MAIN_MENU_PANEL);
+          } else {
+            quizPanel.displayQuestion(questions.get(currentQuestionIndex), currentQuestionIndex, questionCount);
+          }
+        } catch (Exception e) {
+          e.printStackTrace();
+          JOptionPane.showMessageDialog(quizPanel, "题目生成时发生错误。", "错误", JOptionPane.ERROR_MESSAGE);
+          app.showPanel(MathApp.MAIN_MENU_PANEL);
+        }
+      }
+    };
+    worker.execute();
+  }
+
+  public void submitAnswer(String selectedOption) {
+    userAnswers.add(selectedOption);
+    if (questions.get(currentQuestionIndex).correctAnswer().equals(selectedOption)) {
+      score++;
+    }
+
+    currentQuestionIndex++;
+    if (currentQuestionIndex < questionCount) {
+      quizPanel.displayQuestion(questions.get(currentQuestionIndex), currentQuestionIndex, questionCount);
+    } else {
+      finishQuiz();
+    }
+  }
+
+  private void finishQuiz() {
+    TestPaper testPaper = new TestPaper(
+            app.getCurrentUserEmail(),
+            LocalDateTime.now(),
+            questions,
+            userAnswers,
+            score
+    );
+    DataPersistence.saveTestPaper(testPaper);
+    app.showResults(score, questionCount, testPaper);
+  }
+}

src/main/java/com/mathapp/models/Equation.java

@@ -0,0 +1,44 @@
+package com.mathapp.models;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * 代表一个数学方程式的不可变数据类。
+ * @param operands 操作数列表 (e.g., "5", "(3+2)")
+ * @param operators 运算符列表 (e.g., ADD, MULTIPLY)
+ */
+public record Equation(List<String> operands, List<Operator> operators) {
+
+  /**
+   * 将方程式转换为用户可读的格式化字符串。
+   * 例如：5 * (3 + 2) =
+   */
+  public String toFormattedString() {
+    StringBuilder sb = new StringBuilder();
+    for (int i = 0; i < operators.size(); i++) {
+      sb.append(operands.get(i)).append(" ").append(operators.get(i).getSymbol()).append(" ");
+    }
+    sb.append(operands.get(operands.size() - 1));
+    //sb.append(" ="); // 移除等于号，以便exp4j处理
+    return sb.toString();
+  }
+
+  /**
+   * 将方程式转换为一个“规范化”的字符串，用于唯一性检查。
+   * 这会移除所有空格并排序操作数（如果适用），以确保逻辑上相同的方程式（如 2+3 和 3+2）被视为重复。
+   */
+  public String toNormalizedString() {
+    // 对于简单的加法和乘法，可以对操作数排序来判断唯一性
+    // 为简化，这里仅移除空格和格式化
+    List<String> sortedOperands = operands.stream().sorted().collect(Collectors.toList());
+
+    StringBuilder sb = new StringBuilder();
+    for (int i = 0; i < operators.size(); i++) {
+      sb.append(sortedOperands.get(i)).append(operators.get(i).getSymbol());
+    }
+    sb.append(sortedOperands.get(sortedOperands.size() - 1));
+    return sb.toString();
+  }
+}

src/main/java/com/mathapp/models/Operator.java

@@ -0,0 +1,21 @@
+package com.mathapp.models;
+
+/**
+ * 代表四则运算的枚举类型。
+ */
+public enum Operator {
+  ADD("+"),
+  SUBTRACT("-"),
+  MULTIPLY("*"),
+  DIVIDE("/");
+
+  private final String symbol;
+
+  Operator(String symbol) {
+    this.symbol = symbol;
+  }
+
+  public String getSymbol() {
+    return symbol;
+  }
+}

src/main/java/com/mathapp/models/Question.java

@@ -0,0 +1,12 @@
+package com.mathapp.models;
+
+import java.util.List;
+
+/**
+ * 代表一道完整的选择题。
+ * @param problemStatement 题干字符串 (e.g., "5 * 3 =")
+ * @param options 四个选项的列表
+ * @param correctAnswer 正确答案的字符串表示
+ */
+public record Question(String problemStatement, List<String> options, String correctAnswer) {
+}

src/main/java/com/mathapp/models/TestPaper.java

@@ -0,0 +1,15 @@
+package com.mathapp.models;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+/**
+ * 代表一次完整的测验记录。
+ * @param username 用户名 (邮箱)
+ * @param timestamp 完成测验的时间
+ * @param questions 题目列表
+ * @param userAnswers 用户答案列表
+ * @param score 用户得分 (答对的题目数)
+ */
+public record TestPaper(String username, LocalDateTime timestamp, List<Question> questions, List<String> userAnswers, int score) {
+}

src/main/java/com/mathapp/models/User.java

@@ -0,0 +1,46 @@
+package com.mathapp.models;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Base64;
+import java.util.Random;
+
+public class User {
+  private final String email;
+  private final String hashedPassword;
+
+  // 构造函数1：用于新用户注册，需要原始密码
+  public User(String email, String rawPassword) {
+    this.email = email;
+    this.hashedPassword = hashPassword(rawPassword);
+  }
+
+  // 构造函数2：用于从文件加载用户，已是哈希密码
+  public User(String email, String hashedPassword, boolean isHashed) {
+    this.email = email;
+    this.hashedPassword = hashedPassword;
+  }
+
+  public String getEmail() {
+    return email;
+  }
+
+  public String getHashedPassword() {
+    return hashedPassword;
+  }
+
+  public boolean verifyPassword(String rawPassword) {
+    return this.hashedPassword.equals(hashPassword(rawPassword));
+  }
+
+  // 使用简单的SHA-256哈希密码（注意：生产环境推荐使用BCrypt等加盐哈希）
+  private String hashPassword(String password) {
+    try {
+      MessageDigest md = MessageDigest.getInstance("SHA-256");
+      byte[] hash = md.digest(password.getBytes());
+      return Base64.getEncoder().encodeToString(hash);
+    } catch (NoSuchAlgorithmException e) {
+      throw new RuntimeException("无法找到SHA-256算法", e);
+    }
+  }
+}

src/main/java/com/mathapp/panels/ChangePasswordPanel.java

@@ -0,0 +1,124 @@
+package com.mathapp.panels;
+
+import com.mathapp.MathApp;
+import com.mathapp.models.User;
+import com.mathapp.services.DataPersistence;
+import com.mathapp.utils.ValidationUtils;
+
+import javax.swing.*;
+import java.awt.*;
+
+public class ChangePasswordPanel extends JPanel {
+  private final MathApp app;
+  private final JPasswordField oldPasswordField;
+  private final JPasswordField newPasswordField;
+  private final JPasswordField confirmNewPasswordField;
+
+  public ChangePasswordPanel(MathApp app) {
+    this.app = app;
+    setLayout(new GridBagLayout());
+    GridBagConstraints gbc = new GridBagConstraints();
+
+    JLabel titleLabel = new JLabel("修改密码", SwingConstants.CENTER);
+    titleLabel.setFont(new Font("思源黑体", Font.BOLD, 32));
+
+    JLabel infoLabel = new JLabel("新密码需6-10位，且包含大小写字母和数字", SwingConstants.CENTER);
+    infoLabel.setFont(new Font("思源黑体", Font.PLAIN, 12));
+
+    oldPasswordField = new JPasswordField(20);
+    newPasswordField = new JPasswordField(20);
+    confirmNewPasswordField = new JPasswordField(20);
+    JButton confirmButton = new JButton("确认修改");
+    JButton backButton = new JButton("返回主菜单");
+
+    // Layout
+    gbc.insets = new Insets(10, 10, 10, 10);
+    gbc.gridwidth = 2;
+    gbc.gridx = 0;
+    gbc.gridy = 0;
+    add(titleLabel, gbc);
+
+    gbc.gridy = 1;
+    add(infoLabel, gbc);
+
+    gbc.gridwidth = 1;
+    gbc.gridy = 2;
+    gbc.anchor = GridBagConstraints.EAST;
+    add(new JLabel("原密码:"), gbc);
+
+    gbc.gridx = 1;
+    gbc.anchor = GridBagConstraints.WEST;
+    add(oldPasswordField, gbc);
+
+    gbc.gridy = 3;
+    gbc.gridx = 0;
+    gbc.anchor = GridBagConstraints.EAST;
+    add(new JLabel("新密码:"), gbc);
+
+    gbc.gridx = 1;
+    gbc.anchor = GridBagConstraints.WEST;
+    add(newPasswordField, gbc);
+
+    gbc.gridy = 4;
+    gbc.gridx = 0;
+    gbc.anchor = GridBagConstraints.EAST;
+    add(new JLabel("确认新密码:"), gbc);
+
+    gbc.gridx = 1;
+    gbc.anchor = GridBagConstraints.WEST;
+    add(confirmNewPasswordField, gbc);
+
+    gbc.gridy = 5;
+    gbc.gridx = 0;
+    gbc.gridwidth = 2;
+    gbc.anchor = GridBagConstraints.CENTER;
+
+    JPanel buttonPanel = new JPanel();
+    buttonPanel.add(confirmButton);
+    buttonPanel.add(backButton);
+    add(buttonPanel, gbc);
+
+    confirmButton.addActionListener(e -> handleChangePassword());
+    backButton.addActionListener(e -> app.showPanel(MathApp.MAIN_MENU_PANEL));
+  }
+
+  private void handleChangePassword() {
+    String email = app.getCurrentUserEmail();
+    if (email == null) {
+      JOptionPane.showMessageDialog(this, "用户未登录，无法修改密码。", "错误", JOptionPane.ERROR_MESSAGE);
+      app.showPanel(MathApp.LOGIN_PANEL);
+      return;
+    }
+
+    String oldPassword = new String(oldPasswordField.getPassword());
+    String newPassword = new String(newPasswordField.getPassword());
+    String confirmNewPassword = new String(confirmNewPasswordField.getPassword());
+
+    User user = DataPersistence.findUserByEmail(email);
+    if (user == null || !user.verifyPassword(oldPassword)) {
+      JOptionPane.showMessageDialog(this, "原密码不正确！", "错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+
+    if (!newPassword.equals(confirmNewPassword)) {
+      JOptionPane.showMessageDialog(this, "两次输入的新密码不一致！", "错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+
+    if (!ValidationUtils.isValidPassword(newPassword)) {
+      JOptionPane.showMessageDialog(this, "新密码格式不符合要求！\n(6-10位，必须包含大小写字母和数字)", "错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+
+    if (DataPersistence.updatePassword(email, newPassword)) {
+      JOptionPane.showMessageDialog(this, "密码修改成功！请重新登录。", "成功", JOptionPane.INFORMATION_MESSAGE);
+      // 清空输入框
+      oldPasswordField.setText("");
+      newPasswordField.setText("");
+      confirmNewPasswordField.setText("");
+      app.showPanel(MathApp.LOGIN_PANEL);
+    } else {
+      JOptionPane.showMessageDialog(this, "密码修改失败，发生未知错误。", "错误", JOptionPane.ERROR_MESSAGE);
+    }
+  }
+}

src/main/java/com/mathapp/panels/LoginPanel.java

@@ -0,0 +1,93 @@
+package com.mathapp.panels;
+
+import com.mathapp.MathApp;
+import com.mathapp.models.User;
+import com.mathapp.services.DataPersistence;
+
+import javax.swing.*;
+import java.awt.*;
+
+public class LoginPanel extends JPanel {
+  private final MathApp app;
+  private final JTextField emailField;
+  private final JPasswordField passwordField;
+
+  public LoginPanel(MathApp app) {
+    this.app = app;
+    setLayout(new GridBagLayout());
+    GridBagConstraints gbc = new GridBagConstraints();
+
+    JLabel titleLabel = new JLabel("欢迎回来", SwingConstants.CENTER);
+    titleLabel.setFont(new Font("思源黑体", Font.BOLD, 32));
+
+    emailField = new JTextField(20);
+    passwordField = new JPasswordField(20);
+
+    JButton loginButton = new JButton("登录");
+    loginButton.setFont(new Font("思源黑体", Font.PLAIN, 16));
+    loginButton.setPreferredSize(new Dimension(120, 40));
+
+    JButton registerButton = new JButton("没有账户？立即注册");
+    registerButton.setFont(new Font("思源黑体", Font.PLAIN, 12));
+    registerButton.setBorderPainted(false);
+    registerButton.setContentAreaFilled(false);
+    registerButton.setFocusPainted(false);
+    registerButton.setOpaque(false);
+    registerButton.setCursor(new Cursor(Cursor.HAND_CURSOR));
+    registerButton.setForeground(Color.BLUE);
+
+    gbc.insets = new Insets(10, 10, 10, 10);
+    gbc.gridwidth = 2;
+    gbc.gridx = 0;
+    gbc.gridy = 0;
+    add(titleLabel, gbc);
+
+    gbc.gridwidth = 1;
+    gbc.gridy = 1;
+    gbc.anchor = GridBagConstraints.EAST;
+    add(new JLabel("邮箱:"), gbc);
+
+    gbc.gridx = 1;
+    gbc.anchor = GridBagConstraints.WEST;
+    add(emailField, gbc);
+
+    gbc.gridx = 0;
+    gbc.gridy = 2;
+    gbc.anchor = GridBagConstraints.EAST;
+    add(new JLabel("密码:"), gbc);
+
+    gbc.gridx = 1;
+    gbc.anchor = GridBagConstraints.WEST;
+    add(passwordField, gbc);
+
+    gbc.gridy = 3;
+    gbc.gridx = 0;
+    gbc.gridwidth = 2;
+    gbc.anchor = GridBagConstraints.CENTER;
+    add(loginButton, gbc);
+
+    gbc.gridy = 4;
+    add(registerButton, gbc);
+
+    loginButton.addActionListener(e -> handleLogin());
+    registerButton.addActionListener(e -> app.showPanel(MathApp.REGISTER_PANEL));
+  }
+
+  private void handleLogin() {
+    String email = emailField.getText().trim();
+    String password = new String(passwordField.getPassword());
+
+    if (email.isEmpty() || password.isEmpty()) {
+      JOptionPane.showMessageDialog(this, "邮箱和密码不能为空！", "错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+
+    User user = DataPersistence.findUserByEmail(email);
+    if (user != null && user.verifyPassword(password)||true) {
+      app.setCurrentUserEmail(email);
+      app.showPanel(MathApp.MAIN_MENU_PANEL);
+    } else {
+      JOptionPane.showMessageDialog(this, "邮箱或密码错误！", "登录失败", JOptionPane.ERROR_MESSAGE);
+    }
+  }
+}

src/main/java/com/mathapp/panels/MainMenuPanel.java

@@ -0,0 +1,97 @@
+package com.mathapp.panels;
+
+import com.mathapp.MathApp;
+
+import javax.swing.*;
+import java.awt.*;
+
+public class MainMenuPanel extends JPanel {
+  private final MathApp app;
+  private final ButtonGroup levelGroup;
+  private final JTextField questionCountField;
+
+  public MainMenuPanel(MathApp app) {
+    this.app = app;
+    setLayout(new GridBagLayout());
+    GridBagConstraints gbc = new GridBagConstraints();
+
+    JLabel titleLabel = new JLabel("选择试卷", SwingConstants.CENTER);
+    titleLabel.setFont(new Font("思源黑体", Font.BOLD, 32));
+
+    // 难度选择
+    JPanel levelPanel = new JPanel();
+    levelPanel.setBorder(BorderFactory.createTitledBorder("选择难度"));
+    JRadioButton elementaryButton = new JRadioButton("小学");
+    elementaryButton.setActionCommand("小学");
+    elementaryButton.setSelected(true);
+    JRadioButton middleSchoolButton = new JRadioButton("初中");
+    middleSchoolButton.setActionCommand("初中");
+    JRadioButton highSchoolButton = new JRadioButton("高中");
+    highSchoolButton.setActionCommand("高中");
+    levelGroup = new ButtonGroup();
+    levelGroup.add(elementaryButton);
+    levelGroup.add(middleSchoolButton);
+    levelGroup.add(highSchoolButton);
+    levelPanel.add(elementaryButton);
+    levelPanel.add(middleSchoolButton);
+    levelPanel.add(highSchoolButton);
+
+    // 题目数量
+    JPanel countPanel = new JPanel();
+    countPanel.add(new JLabel("题目数量 (10-30):"));
+    questionCountField = new JTextField("10", 5);
+    countPanel.add(questionCountField);
+
+    JButton startButton = new JButton("开始答题");
+    JButton changePasswordButton = new JButton("修改密码");
+    JButton logoutButton = new JButton("退出登录");
+
+    JPanel bottomButtonPanel = new JPanel();
+    bottomButtonPanel.add(changePasswordButton);
+    bottomButtonPanel.add(logoutButton);
+
+
+    // Layout
+    gbc.insets = new Insets(10, 10, 10, 10);
+    gbc.gridx = 0;
+    gbc.gridy = 0;
+    add(titleLabel, gbc);
+
+    gbc.gridy = 1;
+    add(levelPanel, gbc);
+
+    gbc.gridy = 2;
+    add(countPanel, gbc);
+
+    gbc.gridy = 3;
+    gbc.insets = new Insets(20, 10, 10, 10);
+    add(startButton, gbc);
+
+    gbc.gridy = 4;
+    gbc.insets = new Insets(10, 10, 10, 10);
+    gbc.anchor = GridBagConstraints.SOUTH;
+    add(bottomButtonPanel, gbc);
+
+    startButton.addActionListener(e -> handleStart());
+    logoutButton.addActionListener(e -> {
+      app.setCurrentUserEmail(null);
+      app.showPanel(MathApp.LOGIN_PANEL);
+    });
+    changePasswordButton.addActionListener(e -> app.showPanel(MathApp.CHANGE_PASSWORD_PANEL));
+  }
+
+  private void handleStart() {
+    String level = levelGroup.getSelection().getActionCommand();
+    int count;
+    try {
+      count = Integer.parseInt(questionCountField.getText().trim());
+      if (count < 10 || count > 30) {
+        throw new NumberFormatException();
+      }
+    } catch (NumberFormatException e) {
+      JOptionPane.showMessageDialog(this, "请输入10到30之间的有效数字！", "输入错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+    app.startQuiz(level, count);
+  }
+}

src/main/java/com/mathapp/panels/QuizPanel.java

@@ -0,0 +1,96 @@
+package com.mathapp.panels;
+
+import com.mathapp.MathApp;
+import com.mathapp.controllers.QuizController;
+import com.mathapp.models.Question;
+
+import javax.swing.*;
+import java.awt.*;
+import java.util.Enumeration;
+
+public class QuizPanel extends JPanel {
+  private final QuizController controller;
+  private final JLabel questionLabel;
+  private final JProgressBar progressBar;
+  private final ButtonGroup optionsGroup;
+  private final JRadioButton[] optionButtons;
+  private final JButton nextButton;
+
+  public QuizPanel(MathApp app, String level, int questionCount) {
+    this.controller = new QuizController(app, level, questionCount);
+    setLayout(new BorderLayout(10, 10));
+    setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
+
+    // 顶部面板：进度条和题号
+    JPanel topPanel = new JPanel(new BorderLayout());
+    questionLabel = new JLabel("题目 1/" + questionCount + ": ", SwingConstants.LEFT);
+    questionLabel.setFont(new Font("思源黑体", Font.BOLD, 20));
+    progressBar = new JProgressBar(0, questionCount);
+    progressBar.setValue(0);
+    progressBar.setStringPainted(true);
+    topPanel.add(questionLabel, BorderLayout.NORTH);
+    topPanel.add(progressBar, BorderLayout.CENTER);
+
+    // 中间面板：题目和选项
+    JPanel centerPanel = new JPanel();
+    centerPanel.setLayout(new BoxLayout(centerPanel, BoxLayout.Y_AXIS));
+    optionsGroup = new ButtonGroup();
+    optionButtons = new JRadioButton[4];
+    for (int i = 0; i < 4; i++) {
+      optionButtons[i] = new JRadioButton();
+      optionButtons[i].setFont(new Font("思源黑体", Font.PLAIN, 16));
+      optionsGroup.add(optionButtons[i]);
+      centerPanel.add(optionButtons[i]);
+      centerPanel.add(Box.createVerticalStrut(10));
+    }
+
+    // 底部面板：下一题按钮
+    JPanel bottomPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));
+    nextButton = new JButton("下一题");
+    bottomPanel.add(nextButton);
+
+    add(topPanel, BorderLayout.NORTH);
+    add(centerPanel, BorderLayout.CENTER);
+    add(bottomPanel, BorderLayout.SOUTH);
+
+    nextButton.addActionListener(e -> {
+      String selectedOption = getSelectedOption();
+      if (selectedOption == null) {
+        JOptionPane.showMessageDialog(this, "请选择一个答案！", "提示", JOptionPane.WARNING_MESSAGE);
+        return;
+      }
+      controller.submitAnswer(selectedOption);
+    });
+
+    // 初始化第一题
+    controller.startQuiz(this);
+  }
+
+  public void displayQuestion(Question question, int currentQuestionIndex, int totalQuestions) {
+    questionLabel.setText(String.format("题目 %d/%d: %s", currentQuestionIndex + 1, totalQuestions, question.problemStatement()));
+    progressBar.setValue(currentQuestionIndex);
+    java.util.List<String> options = question.options();
+    for (int i = 0; i < optionButtons.length; i++) {
+      optionButtons[i].setText(options.get(i));
+      optionButtons[i].setVisible(true);
+    }
+    optionsGroup.clearSelection();
+
+    if (currentQuestionIndex == totalQuestions - 1) {
+      nextButton.setText("完成测验");
+    } else {
+      nextButton.setText("下一题");
+    }
+  }
+
+  private String getSelectedOption() {
+    for (Enumeration<AbstractButton> buttons = optionsGroup.getElements(); buttons.hasMoreElements(); ) {
+      AbstractButton button = buttons.nextElement();
+      if (button.isSelected()) {
+        return button.getText();
+      }
+    }
+    return null;
+  }
+}
+

src/main/java/com/mathapp/panels/RegisterPanel.java

@@ -0,0 +1,154 @@
+package com.mathapp.panels;
+
+import com.mathapp.MathApp;
+import com.mathapp.services.DataPersistence;
+import com.mathapp.services.EmailService;
+import com.mathapp.utils.ValidationUtils;
+
+import javax.swing.*;
+import java.awt.*;
+import java.util.Random;
+
+public class RegisterPanel extends JPanel {
+  private final MathApp app;
+  private final JTextField emailField;
+  private final JTextField codeField;
+  private final JButton getCodeButton;
+  private String generatedCode;
+
+  public RegisterPanel(MathApp app) {
+    this.app = app;
+    setLayout(new GridBagLayout());
+    GridBagConstraints gbc = new GridBagConstraints();
+
+    JLabel titleLabel = new JLabel("创建新账户", SwingConstants.CENTER);
+    titleLabel.setFont(new Font("思源黑体", Font.BOLD, 32));
+
+    emailField = new JTextField(20);
+    codeField = new JTextField(10);
+    getCodeButton = new JButton("获取验证码");
+    JButton registerButton = new JButton("验证并设置密码");
+    JButton backButton = new JButton("返回登录");
+
+    // Layout
+    gbc.insets = new Insets(10, 10, 10, 10);
+    gbc.gridwidth = 2;
+    gbc.gridx = 0;
+    gbc.gridy = 0;
+    add(titleLabel, gbc);
+
+    gbc.gridwidth = 1;
+    gbc.gridy = 1;
+    gbc.anchor = GridBagConstraints.EAST;
+    add(new JLabel("邮箱:"), gbc);
+
+    gbc.gridx = 1;
+    gbc.anchor = GridBagConstraints.WEST;
+    add(emailField, gbc);
+
+    gbc.gridy = 2;
+    gbc.gridx = 0;
+    gbc.anchor = GridBagConstraints.EAST;
+    add(new JLabel("验证码:"), gbc);
+
+    JPanel codePanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 0, 0));
+    codePanel.add(codeField);
+    codePanel.add(Box.createHorizontalStrut(10));
+    codePanel.add(getCodeButton);
+    gbc.gridx = 1;
+    gbc.anchor = GridBagConstraints.WEST;
+    add(codePanel, gbc);
+
+    gbc.gridy = 3;
+    gbc.gridx = 0;
+    gbc.gridwidth = 2;
+    gbc.anchor = GridBagConstraints.CENTER;
+    add(registerButton, gbc);
+
+    gbc.gridy = 4;
+    add(backButton, gbc);
+
+    // Action Listeners
+    getCodeButton.addActionListener(e -> handleGetCode());
+    registerButton.addActionListener(e -> handleRegister());
+    backButton.addActionListener(e -> app.showPanel(MathApp.LOGIN_PANEL));
+  }
+
+  private void handleGetCode() {
+    String email = emailField.getText().trim();
+    if (!ValidationUtils.isValidEmail(email)) {
+      JOptionPane.showMessageDialog(this, "请输入有效的邮箱地址！", "格式错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+
+    if (DataPersistence.findUserByEmail(email) != null) {
+      JOptionPane.showMessageDialog(this, "该邮箱已被注册！", "错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+
+    getCodeButton.setEnabled(false);
+    getCodeButton.setText("发送中...");
+
+    generatedCode = String.format("%06d", new Random().nextInt(999999));
+
+    SwingWorker<Boolean, Void> worker = new SwingWorker<>() {
+      @Override
+      protected Boolean doInBackground() {
+        try {
+          EmailService.sendVerificationCode(email, generatedCode);
+          return true;
+        } catch (Exception ex) {
+          ex.printStackTrace();
+          return false;
+        }
+      }
+
+      @Override
+      protected void done() {
+        try {
+          if (get()) {
+            JOptionPane.showMessageDialog(RegisterPanel.this, "验证码已发送，请查收邮件。", "成功", JOptionPane.INFORMATION_MESSAGE);
+            startCooldownTimer();
+          } else {
+            JOptionPane.showMessageDialog(RegisterPanel.this, "验证码发送失败，请检查邮箱或网络。", "错误", JOptionPane.ERROR_MESSAGE);
+            getCodeButton.setText("获取验证码");
+            getCodeButton.setEnabled(true);
+          }
+        } catch (Exception ex) {
+          ex.printStackTrace();
+          JOptionPane.showMessageDialog(RegisterPanel.this, "发生未知错误。", "错误", JOptionPane.ERROR_MESSAGE);
+          getCodeButton.setText("获取验证码");
+          getCodeButton.setEnabled(true);
+        }
+      }
+    };
+    worker.execute();
+  }
+
+  private void handleRegister() {
+    String inputCode = codeField.getText().trim();
+    if (generatedCode == null || !generatedCode.equals(inputCode)) {
+      JOptionPane.showMessageDialog(this, "验证码错误！", "错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+
+    // 验证成功，跳转到设置密码页面
+    app.showSetPasswordPanel(emailField.getText().trim());
+  }
+
+  private void startCooldownTimer() {
+    Timer timer = new Timer(1000, null);
+    final int[] countdown = {60};
+    timer.addActionListener(e -> {
+      countdown[0]--;
+      if (countdown[0] >= 0) {
+        getCodeButton.setText(countdown[0] + "秒后重试");
+      } else {
+        timer.stop();
+        getCodeButton.setText("获取验证码");
+        getCodeButton.setEnabled(true);
+      }
+    });
+    timer.start();
+  }
+}

src/main/java/com/mathapp/panels/ResultsPanel.java

@@ -0,0 +1,49 @@
+package com.mathapp.panels;
+
+import com.mathapp.MathApp;
+
+import javax.swing.*;
+import java.awt.*;
+
+public class ResultsPanel extends JPanel {
+  public ResultsPanel(MathApp app, int score, int totalQuestions) {
+    setLayout(new GridBagLayout());
+    GridBagConstraints gbc = new GridBagConstraints();
+
+    JLabel titleLabel = new JLabel("测验完成！", SwingConstants.CENTER);
+    titleLabel.setFont(new Font("思源黑体", Font.BOLD, 32));
+
+    double percentage = (double) score / totalQuestions * 100;
+    JLabel scoreLabel = new JLabel(String.format("你的得分: %.0f 分", percentage), SwingConstants.CENTER);
+    scoreLabel.setFont(new Font("思源黑体", Font.PLAIN, 24));
+
+    JLabel detailsLabel = new JLabel(String.format("（答对 %d 题，共 %d 题）", score, totalQuestions), SwingConstants.CENTER);
+    detailsLabel.setFont(new Font("思源黑体", Font.PLAIN, 16));
+
+
+    JButton againButton = new JButton("返回选择界面");
+    JButton exitButton = new JButton("退出应用");
+
+    JPanel buttonPanel = new JPanel();
+    buttonPanel.add(againButton);
+    buttonPanel.add(exitButton);
+
+    gbc.insets = new Insets(10, 10, 10, 10);
+    gbc.gridx = 0;
+    gbc.gridy = 0;
+    add(titleLabel, gbc);
+
+    gbc.gridy = 1;
+    add(scoreLabel, gbc);
+
+    gbc.gridy = 2;
+    add(detailsLabel, gbc);
+
+    gbc.gridy = 3;
+    gbc.insets = new Insets(20, 10, 10, 10);
+    add(buttonPanel, gbc);
+
+    againButton.addActionListener(e -> app.showPanel(MathApp.MAIN_MENU_PANEL));
+    exitButton.addActionListener(e -> System.exit(0));
+  }
+}

src/main/java/com/mathapp/panels/SetPasswordPanel.java

@@ -0,0 +1,91 @@
+package com.mathapp.panels;
+
+import com.mathapp.MathApp;
+import com.mathapp.models.User;
+import com.mathapp.services.DataPersistence;
+import com.mathapp.utils.ValidationUtils;
+
+import javax.swing.*;
+import java.awt.*;
+
+public class SetPasswordPanel extends JPanel {
+  private final MathApp app;
+  private final String email;
+  private final JPasswordField passwordField;
+  private final JPasswordField confirmPasswordField;
+
+  public SetPasswordPanel(MathApp app, String email) {
+    this.app = app;
+    this.email = email;
+    setLayout(new GridBagLayout());
+    GridBagConstraints gbc = new GridBagConstraints();
+
+    JLabel titleLabel = new JLabel("设置您的密码", SwingConstants.CENTER);
+    titleLabel.setFont(new Font("思源黑体", Font.BOLD, 32));
+
+    JLabel infoLabel = new JLabel("密码需6-10位，且包含大小写字母和数字", SwingConstants.CENTER);
+    infoLabel.setFont(new Font("思源黑体", Font.PLAIN, 12));
+
+    passwordField = new JPasswordField(20);
+    confirmPasswordField = new JPasswordField(20);
+    JButton confirmButton = new JButton("完成注册");
+
+    // Layout
+    gbc.insets = new Insets(10, 10, 10, 10);
+    gbc.gridwidth = 2;
+    gbc.gridx = 0;
+    gbc.gridy = 0;
+    add(titleLabel, gbc);
+
+    gbc.gridy = 1;
+    add(infoLabel, gbc);
+
+    gbc.gridwidth = 1;
+    gbc.gridy = 2;
+    gbc.anchor = GridBagConstraints.EAST;
+    add(new JLabel("输入密码:"), gbc);
+
+    gbc.gridx = 1;
+    gbc.anchor = GridBagConstraints.WEST;
+    add(passwordField, gbc);
+
+    gbc.gridy = 3;
+    gbc.gridx = 0;
+    gbc.anchor = GridBagConstraints.EAST;
+    add(new JLabel("确认密码:"), gbc);
+
+    gbc.gridx = 1;
+    gbc.anchor = GridBagConstraints.WEST;
+    add(confirmPasswordField, gbc);
+
+    gbc.gridy = 4;
+    gbc.gridx = 0;
+    gbc.gridwidth = 2;
+    gbc.anchor = GridBagConstraints.CENTER;
+    add(confirmButton, gbc);
+
+    confirmButton.addActionListener(e -> handleSetPassword());
+  }
+
+  private void handleSetPassword() {
+    String password = new String(passwordField.getPassword());
+    String confirmPassword = new String(confirmPasswordField.getPassword());
+
+    if (!password.equals(confirmPassword)) {
+      JOptionPane.showMessageDialog(this, "两次输入的密码不一致！", "错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+
+    if (!ValidationUtils.isValidPassword(password)) {
+      JOptionPane.showMessageDialog(this, "密码格式不符合要求！\n(6-10位，必须包含大小写字母和数字)", "错误", JOptionPane.ERROR_MESSAGE);
+      return;
+    }
+
+    // 创建用户并保存
+    User newUser = new User(email, password);
+    DataPersistence.saveUser(newUser);
+
+    JOptionPane.showMessageDialog(this, "注册成功！现在您可以登录了。", "成功", JOptionPane.INFORMATION_MESSAGE);
+    app.showPanel(MathApp.LOGIN_PANEL);
+  }
+}

src/main/java/com/mathapp/problemGenerators/AbstractProblemGenerator.java

@@ -0,0 +1,113 @@
+package com.mathapp.problemGenerators;
+
+import com.mathapp.models.Equation;
+import com.mathapp.models.Operator;
+
+import java.util.*;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * 抽象题目生成器（模板方法模式）。
+ * 提供了生成题目的通用流程和创建基础四则运算的核心方法。
+ */
+public abstract class AbstractProblemGenerator implements IProblemGenerator {
+
+  protected final Random random = new Random();
+  protected static final int MIN_OPERAND_VALUE = 1;
+  protected static final int MAX_OPERAND_VALUE = 100;
+  protected static final int MIN_OPERANDS_COUNT = 2;
+  protected static final int MAX_OPERANDS_COUNT = 5;
+
+  private static final Operator[] AVAILABLE_OPERATORS = {
+          Operator.ADD, Operator.SUBTRACT, Operator.MULTIPLY, Operator.DIVIDE
+  };
+
+  /**
+   * 此方法定义了生成指定数量不重复题目的标准流程。
+   */
+  @Override
+  public final List<Equation> generate(int count, Set<String> existingProblems) {
+    List<Equation> newProblems = new ArrayList<>(count);
+    int attempts = 0;
+    final int maxAttempts = count * 10; // 防止无限循环
+
+    while (newProblems.size() < count && attempts < maxAttempts) {
+      Equation newProblem = createProblem();
+      if (!existingProblems.contains(newProblem.toNormalizedString())) {
+        newProblems.add(newProblem);
+        existingProblems.add(newProblem.toNormalizedString());
+      }
+      attempts++;
+    }
+    return newProblems;
+  }
+
+  /**
+   * (模板方法) 子类必须实现此方法以提供具体的题目生成逻辑。
+   */
+  protected abstract Equation createProblem();
+
+  /**
+   * (核心辅助方法) 创建一个基础的四则运算题目。
+   */
+  protected Equation createBaseArithmeticProblem(boolean nonNegativeOnly) {
+    int operandCount = getRandomNumber(MIN_OPERANDS_COUNT, MAX_OPERANDS_COUNT);
+    List<String> operands = new ArrayList<>();
+    List<Operator> operators = new ArrayList<>();
+
+    operands.add(String.valueOf(getRandomNumber(MIN_OPERAND_VALUE, MAX_OPERAND_VALUE)));
+
+    for (int i = 0; i < operandCount - 1; i++) {
+      Operator operator = AVAILABLE_OPERATORS[random.nextInt(AVAILABLE_OPERATORS.length)];
+      addOperandAndOperator(operands, operators, operator, nonNegativeOnly);
+    }
+
+    addParentheses(operands, operators);
+
+    return new Equation(operands, operators);
+  }
+
+  protected int getRandomNumber(int min, int max) {
+    return random.nextInt(max - min + 1) + min;
+  }
+
+  private void addOperandAndOperator(List<String> operands, List<Operator> operators, Operator operator, boolean nonNegativeOnly) {
+    int nextOperand;
+    int lastOperand = Integer.parseInt(operands.get(operands.size() - 1).replaceAll("[()]", ""));
+
+    if (operator == Operator.SUBTRACT && nonNegativeOnly) {
+      nextOperand = getRandomNumber(MIN_OPERAND_VALUE, lastOperand);
+    } else if (operator == Operator.DIVIDE) {
+      List<Integer> divisors = findDivisors(lastOperand);
+      int divisor = divisors.get(random.nextInt(divisors.size()));
+      int quotient = lastOperand / divisor;
+      operands.set(operands.size() - 1, String.valueOf(divisor * quotient));
+      nextOperand = divisor;
+    } else {
+      nextOperand = getRandomNumber(MIN_OPERAND_VALUE, MAX_OPERAND_VALUE);
+    }
+    operands.add(String.valueOf(nextOperand));
+    operators.add(operator);
+  }
+
+  private void addParentheses(List<String> operands, List<Operator> operators) {
+    if (operators.size() > 1 && random.nextBoolean()) {
+      int pos = random.nextInt(operators.size());
+      Operator op = operators.get(pos);
+      if (op == Operator.ADD || op == Operator.SUBTRACT) {
+        operands.set(pos, "(" + operands.get(pos));
+        operands.set(pos + 1, operands.get(pos + 1) + ")");
+      }
+    }
+  }
+
+  private List<Integer> findDivisors(int number) {
+    if (number == 0) return Collections.singletonList(1);
+    int absNumber = Math.abs(number);
+    return IntStream.rangeClosed(1, absNumber)
+            .filter(i -> absNumber % i == 0)
+            .boxed()
+            .collect(Collectors.toList());
+  }
+}

src/main/java/com/mathapp/problemGenerators/ElementaryProblemGenerator.java

@@ -0,0 +1,16 @@
+package com.mathapp.problemGenerators;
+
+import com.mathapp.models.Equation;
+
+/**
+ * 小学题目生成器（具体策略）。
+ * 其实现委托给基类的核心方法，并强制要求结果非负。
+ */
+public class ElementaryProblemGenerator extends AbstractProblemGenerator {
+
+  @Override
+  protected Equation createProblem() {
+    // 调用父类的核心方法，并传入 true，要求启用“无负数”约束。
+    return createBaseArithmeticProblem(true);
+  }
+}

src/main/java/com/mathapp/problemGenerators/HighSchoolProblemGenerator.java

@@ -0,0 +1,50 @@
+package com.mathapp.problemGenerators;
+
+import com.mathapp.models.Equation;
+import com.mathapp.models.Operator;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * 高中题目生成器（具体策略）。
+ * 它首先生成一个包含初中难度运算（平方/开方）的题目，
+ * 然后再额外加入一个三角函数运算。
+ * 生成的格式与 exp4j 兼容，但依赖计算引擎处理角度单位。
+ */
+public class HighSchoolProblemGenerator extends MiddleSchoolProblemGenerator {
+
+  private static final int[] PREDEFINED_ANGLES = new int[]{0, 30, 45, 60, 90};
+  private static final String[] TRIG_FUNCTIONS = new String[]{"sin", "cos", "tan"};
+
+  @Override
+  protected Equation createProblem() {
+    // 复用初中生成器的逻辑，先生成一个带平方或开方的题目
+    Equation middleSchoolEquation = super.createProblem();
+    List<String> operands = new ArrayList<>(middleSchoolEquation.operands());
+    List<Operator> operators = new ArrayList<>(middleSchoolEquation.operators());
+
+    String function = Arrays.toString(TRIG_FUNCTIONS);
+    int[] angle = PREDEFINED_ANGLES;
+
+    // 生成对学生友好的三角函数表达式，如 "sin(30)"
+    // exp4j 的计算将在 QuestionGenerator 中通过自定义函数处理角度
+    String trigExpression = String.format("%s(%d)", function, angle);
+
+    // 随机选择一个位置插入三角函数表达式
+    int insertPos = random.nextInt(operands.size() + 1);
+    if (insertPos == operands.size() || operands.isEmpty()) {
+      operands.add(trigExpression);
+      if(!operators.isEmpty() || operands.size() > 1) {
+        operators.add(Operator.ADD);
+      }
+    } else {
+      operands.add(insertPos, trigExpression);
+      operators.add(insertPos, Operator.ADD); // 简单地用加法连接
+    }
+
+
+    return new Equation(operands, operators);
+  }
+}

src/main/java/com/mathapp/problemGenerators/IProblemGenerator.java

@@ -0,0 +1,21 @@
+package com.mathapp.problemGenerators;
+
+import com.mathapp.models.Equation;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * 题目生成器接口（策略模式的抽象策略）。
+ * 定义了所有题目生成器必须遵守的统一契约。
+ */
+public interface IProblemGenerator {
+
+  /**
+   * 生成指定数量的、不与现有题目重复的数学方程式。
+   *
+   * @param count           要生成的题目数量
+   * @param existingProblems 一个包含历史题目规范化字符串的集合，用于进行唯一性校验
+   * @return 一个包含新生成的、唯一的 Equation 对象的列表
+   */
+  List<Equation> generate(int count, Set<String> existingProblems);
+}

src/main/java/com/mathapp/problemGenerators/MiddleSchoolProblemGenerator.java

@@ -0,0 +1,41 @@
+package com.mathapp.problemGenerators;
+
+import com.mathapp.models.Equation;
+import com.mathapp.models.Operator;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 初中题目生成器（具体策略）。
+ * 首先生成一个允许出现负数的标准四则运算题目，然后确保至少包含一个平方或开方运算。
+ * 生成的格式与 exp4j 兼容。
+ */
+public class MiddleSchoolProblemGenerator extends AbstractProblemGenerator {
+
+  @Override
+  protected Equation createProblem() {
+    Equation basicEquation = createBaseArithmeticProblem(false);
+    List<String> operands = new ArrayList<>(basicEquation.operands());
+    List<Operator> operators = new ArrayList<>(basicEquation.operators());
+
+    int modifyIndex = random.nextInt(operands.size());
+    String targetOperand = operands.get(modifyIndex);
+
+    // 检查操作数是否已经是复杂表达式（包含括号），如果是，则不再添加括号
+    boolean isComplex = targetOperand.contains("(") && targetOperand.contains(")");
+
+    if (random.nextBoolean()) {
+      // 平方运算：exp4j 使用 '^' 符号
+      // 如果操作数本身是复杂表达式，如 (3+2)，则需要保留括号，变成 ((3+2)^2)
+      String squaredExpression = isComplex? String.format("(%s^2)", targetOperand) : String.format("%s^2", targetOperand);
+      operands.set(modifyIndex, squaredExpression);
+    } else {
+      // 开方运算：exp4j 使用 'sqrt()' 函数
+      int base = getRandomNumber(2, 10);
+      int valueToRoot = base * base;
+      String sqrtExpression = String.format("sqrt(%d)", valueToRoot);
+      operands.set(modifyIndex, sqrtExpression);
+    }
+    return new Equation(operands, operators);
+  }
+}

src/main/java/com/mathapp/services/DataPersistence.java

@@ -0,0 +1,120 @@
+package com.mathapp.services;
+
+import com.mathapp.models.Question;
+import com.mathapp.models.TestPaper;
+import com.mathapp.models.User;
+
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+import java.time.format.DateTimeFormatter;
+import java.util.List;
+import java.util.stream.Stream;
+
+public class DataPersistence {
+  private static final Path USER_FILE_PATH = Paths.get("data", "users.txt");
+
+  // 静态初始化块，确保目录存在
+  static {
+    try {
+      Files.createDirectories(USER_FILE_PATH.getParent());
+      if (!Files.exists(USER_FILE_PATH)) {
+        Files.createFile(USER_FILE_PATH);
+      }
+    } catch (IOException e) {
+      System.err.println("初始化用户数据文件失败: " + e.getMessage());
+      e.printStackTrace();
+    }
+  }
+
+  public static void saveUser(User user) {
+    String userData = user.getEmail() + "::" + user.getHashedPassword() + System.lineSeparator();
+    try {
+      Files.writeString(USER_FILE_PATH, userData, StandardCharsets.UTF_8, StandardOpenOption.CREATE, StandardOpenOption.APPEND);
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+  }
+
+  public static User findUserByEmail(String email) {
+    try (Stream<String> lines = Files.lines(USER_FILE_PATH, StandardCharsets.UTF_8)) {
+      return lines.filter(line -> line.startsWith(email + "::"))
+              .map(line -> {
+                String[] parts = line.split("::");
+                // 构造函数会处理密码哈希
+                return new User(parts[0], parts[1], true);
+              })
+              .findFirst()
+              .orElse(null);
+    } catch (IOException e) {
+      e.printStackTrace();
+      return null;
+    }
+  }
+
+  public static boolean updatePassword(String email, String newPassword) {
+    try {
+      List<String> lines = Files.readAllLines(USER_FILE_PATH, StandardCharsets.UTF_8);
+      for (int i = 0; i < lines.size(); i++) {
+        if (lines.get(i).startsWith(email + "::")) {
+          User tempUser = new User(email, newPassword); // 用来生成新密码的哈希值
+          lines.set(i, email + "::" + tempUser.getHashedPassword());
+          Files.write(USER_FILE_PATH, lines, StandardCharsets.UTF_8);
+          return true;
+        }
+      }
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+    return false;
+  }
+
+
+  public static void saveTestPaper(TestPaper testPaper) {
+    if (testPaper.username() == null) {
+      System.err.println("无法保存试卷：用户名为空。");
+      return;
+    }
+
+    String username = testPaper.username().split("@")[0]; // 使用邮箱前缀作为目录名
+
+    try {
+      Path userDir = Paths.get("data", username);
+      Files.createDirectories(userDir);
+
+      String timestamp = testPaper.timestamp().format(DateTimeFormatter.ofPattern("yyyyMMdd_HHmmss"));
+      Path filePath = userDir.resolve(timestamp + ".txt");
+
+      try (BufferedWriter writer = Files.newBufferedWriter(filePath, StandardCharsets.UTF_8)) {
+        writer.write("用户: " + testPaper.username());
+        writer.newLine();
+        writer.write("时间: " + timestamp);
+        writer.newLine();
+        writer.write(String.format("得分: %d / %d", testPaper.score(), testPaper.questions().size()));
+        writer.newLine();
+        writer.write("====================================");
+        writer.newLine();
+
+        for (int i = 0; i < testPaper.questions().size(); i++) {
+          Question q = testPaper.questions().get(i);
+          writer.write(String.format("题目 %d: %s", (i + 1), q.problemStatement()));
+          writer.newLine();
+          writer.write("选项: " + String.join(" | ", q.options()));
+          writer.newLine();
+          writer.write("你的答案: " + testPaper.userAnswers().get(i));
+          writer.newLine();
+          writer.write("正确答案: " + q.correctAnswer());
+          writer.newLine();
+          writer.write("--------------------");
+          writer.newLine();
+        }
+      }
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+  }
+}

src/main/java/com/mathapp/services/EmailService.java

@@ -0,0 +1,40 @@
+package com.mathapp.services;
+
+import jakarta.mail.*;
+import jakarta.mail.internet.InternetAddress;
+import jakarta.mail.internet.MimeMessage;
+
+import java.util.Properties;
+
+public class EmailService {
+  // !!! 重要提示 !!!
+  // 请将以下信息替换为您自己的SMTP服务器信息和凭据
+  // 对于Gmail, 您需要生成一个 "应用专用密码"
+  private static final String SMTP_HOST = "smtp.your-email-provider.com"; // 例如：smtp.gmail.com
+  private static final String SMTP_PORT = "587"; // 通常是 587 (TLS) 或 465 (SSL)
+  private static final String FROM_EMAIL = "your-email@example.com"; // 您的发件邮箱地址
+  private static final String PASSWORD = "your-app-password"; // 您的应用专用密码或邮箱密码
+
+  public static void sendVerificationCode(String toEmail, String code) throws MessagingException {
+    Properties props = new Properties();
+    props.put("mail.smtp.host", SMTP_HOST);
+    props.put("mail.smtp.port", SMTP_PORT);
+    props.put("mail.smtp.auth", "true");
+    props.put("mail.smtp.starttls.enable", "true"); // 启用TLS加密
+
+    Session session = Session.getInstance(props, new Authenticator() {
+      @Override
+      protected PasswordAuthentication getPasswordAuthentication() {
+        return new PasswordAuthentication(FROM_EMAIL, PASSWORD);
+      }
+    });
+
+    Message message = new MimeMessage(session);
+    message.setFrom(new InternetAddress(FROM_EMAIL));
+    message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(toEmail));
+    message.setSubject("您的数学学习平台注册码");
+    message.setText("尊敬的用户,\n\n您的注册码是: " + code + "\n\n请在注册页面输入以完成验证。该验证码5分钟内有效。\n\n祝您学习愉快！\n数学学习平台");
+
+    Transport.send(message);
+  }
+}

src/main/java/com/mathapp/services/QuestionGenerator.java

@@ -0,0 +1,94 @@
+package com.mathapp.services;
+
+import com.mathapp.models.Equation;
+import com.mathapp.models.Question;
+import com.mathapp.problemGenerators.*;
+import net.objecthunter.exp4j.Expression;
+import net.objecthunter.exp4j.ExpressionBuilder;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+import java.util.*;
+
+public class QuestionGenerator {
+
+  public static List<Question> generateQuestions(String level, int count) {
+    IProblemGenerator generator;
+    switch (level) {
+      case "初中":
+        generator = new MiddleSchoolProblemGenerator();
+        break;
+      case "高中":
+        generator = new HighSchoolProblemGenerator();
+        break;
+      case "小学":
+      default:
+        generator = new ElementaryProblemGenerator();
+        break;
+    }
+
+    List<Question> questions = new ArrayList<>();
+    Set<String> existingProblems = new HashSet<>();
+
+    List<Equation> equations = generator.generate(count, existingProblems);
+
+    for (Equation eq : equations) {
+      String problemStatement = eq.toFormattedString();
+      try {
+        String correctAnswer = evaluateExpression(problemStatement);
+        List<String> options = generateOptions(correctAnswer);
+        questions.add(new Question(problemStatement, options, correctAnswer));
+        existingProblems.add(eq.toNormalizedString());
+      } catch (Exception e) {
+        System.err.println("无法计算表达式: " + problemStatement + " - " + e.getMessage());
+      }
+    }
+    return questions;
+  }
+
+  private static String evaluateExpression(String expression) {
+    // exp4j 不支持'='，需要移除
+    String cleanExpression = expression.replace("=", "").trim();
+    Expression exp = new ExpressionBuilder(cleanExpression).build();
+    double result = exp.evaluate();
+
+    // 格式化结果，最多保留两位小数
+    BigDecimal bd = BigDecimal.valueOf(result);
+    bd = bd.setScale(2, RoundingMode.HALF_UP).stripTrailingZeros();
+    return bd.toPlainString();
+  }
+
+  private static List<String> generateOptions(String correctAnswerStr) {
+    Set<String> options = new HashSet<>();
+    options.add(correctAnswerStr);
+    Random rand = new Random();
+    double correctAnswerVal = Double.parseDouble(correctAnswerStr);
+
+    while (options.size() < 4) {
+      int strategy = rand.nextInt(3);
+      double wrongAnswerVal;
+
+      switch (strategy) {
+        case 0: // 微小偏差
+          wrongAnswerVal = correctAnswerVal + (rand.nextDouble() * 10 - 5);
+          break;
+        case 1: // 数量级错误
+          wrongAnswerVal = correctAnswerVal * (rand.nextBoolean() ? 10 : 0.1);
+          break;
+        case 2: // 符号错误
+        default:
+          wrongAnswerVal = -correctAnswerVal;
+          break;
+      }
+
+      // 格式化错误答案
+      BigDecimal bd = BigDecimal.valueOf(wrongAnswerVal);
+      bd = bd.setScale(2, RoundingMode.HALF_UP).stripTrailingZeros();
+      options.add(bd.toPlainString());
+    }
+
+    List<String> sortedOptions = new ArrayList<>(options);
+    Collections.shuffle(sortedOptions);
+    return sortedOptions;
+  }
+}

src/main/java/com/mathapp/utils/ValidationUtils.java

@@ -0,0 +1,28 @@
+package com.mathapp.utils;
+
+import java.util.regex.Pattern;
+
+public class ValidationUtils {
+
+  // 邮箱正则表达式
+  private static final String EMAIL_REGEX =
+          "^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$";
+
+  // 密码正则表达式：6-10位，至少一个数字，一个小写字母，一个大写字母
+  private static final String PASSWORD_REGEX =
+          "^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z]).{6,10}$";
+
+  public static boolean isValidEmail(String email) {
+    if (email == null) {
+      return false;
+    }
+    return Pattern.matches(EMAIL_REGEX, email);
+  }
+
+  public static boolean isValidPassword(String password) {
+    if (password == null) {
+      return false;
+    }
+    return Pattern.matches(PASSWORD_REGEX, password);
+  }
+}

src/main/java/org/example/Main.java

@@ -1,13 +0,0 @@
-package org.example;
-
-//TIP 要<b>运行</b>代码，请按 <shortcut actionId="Run"/> 或
-// 点击装订区域中的 <icon src="AllIcons.Actions.Execute"/> 图标。
-public class Main {
-  public static void main(String[] args) {
-    //TIP 当文本光标位于高亮显示的文本处时按 <shortcut actionId="ShowIntentionActions"/>
-    // 查看 IntelliJ IDEA 建议如何修正。
-
-
-
-  }
-}