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doc/数学在线考试系统说明文档.md

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+# 数学在线考试系统
+
+## 项目简介
+
+一个基于JavaFX开发的数学在线考试系统，支持用户注册、登录、密码管理和多学段数学题目生成。系统提供小学、初中、高中三个学段的数学题目，支持自动组卷、在线答题和自动评分功能。
+
+## 功能特性
+
+### 用户管理
+
+- 用户注册（邮箱验证）
+- 用户登录（支持邮箱/用户名登录）
+- 密码重置
+- 密码修改
+- 用户信息持久化存储
+
+###  考试功能
+
+- **多学段支持**：小学、初中、高中
+- **智能题目生成**：根据学段生成相应难度题目
+- **题目去重**：同一试卷中不会出现重复题目
+- **实时答题**：在线答题界面，支持题目导航
+- **自动评分**：答题完成后自动计算得分
+- **进度显示**：答题进度可视化
+
+###  题目特点
+
+- **小学**：基础四则运算，确保结果为正数
+- **初中**：包含平方、开方等运算
+- **高中**：包含三角函数等高级运算
+- **选项生成**：智能生成干扰项，避免重复
+
+## 技术架构
+
+### 后端技术栈
+
+- **JavaFX** - 桌面应用框架
+- **Jackson** - JSON数据序列化
+- **Jakarta Mail** - 邮件发送服务
+- **BCrypt** - 密码加密
+- **JUnit** - 单元测试
+
+### 项目结构
+
+```
+src/main/java/com/example/myapp/
+├── controller/          # 控制器层
+│   ├── LoginController.java
+│   ├── RegisterController.java
+│   ├── DashboardController.java
+│   ├── ExamController.java
+│   └── ...
+├── model/              # 数据模型
+│   ├── User.java
+│   ├── Exam.java
+│   ├── Question.java
+│   └── Expression.java
+├── service/            # 业务服务层
+│   ├── UserService.java
+│   ├── ExamService.java
+│   ├── EmailService.java
+│   └── MathQuestionGenerator.java
+├── util/               # 工具类
+│   └── PasswordUtil.java
+└── Main.java           # 应用入口
+```
+
+
+
+## 核心功能模块
+
+### 1. 用户认证系统
+
+java
+
+复制下载
+
+```
+// 密码规则：6-10位，必须包含大小写字母和数字
+public static boolean validatePasswordRules(String pwd) {
+    Pattern validPattern = Pattern.compile("^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d).{6,10}$");
+    return validPattern.matcher(pwd).matches();
+}
+```
+
+
+
+### 2. 题目生成系统
+
+采用工厂模式 + 抽象类实现多学段题目生成：
+
+java
+
+复制下载
+
+```
+// 题目生成工厂
+public class QueSetingFactory {
+    public QuestionSeting getQueSeting(String type) {
+        switch (type) {
+            case "小学": return new PrimaryQueSeting();
+            case "初中": return new MiddleQueSeting();
+            case "高中": return new HighQueSeting();
+            default: return null;
+        }
+    }
+}
+```
+
+
+
+### 3. 数据存储系统
+
+使用JSON文件进行数据持久化：
+
+- `data/users.json` - 用户数据
+- `data/registration_codes.json` - 注册验证码
+- `data/reset_password_codes.json` - 密码重置码
+
+## 安装与运行
+
+### 环境要求
+
+- Java 17 或更高版本
+- Maven 3.6+
+- 可用的SMTP服务器（用于邮件发送）
+
+
+
+## 使用指南
+
+### 用户注册流程
+
+1. 输入邮箱地址
+2. 接收验证码邮件
+3. 输入验证码验证
+4. 设置用户名和密码
+5. 注册完成，进入用户中心
+
+### 考试流程
+
+1. 登录系统
+2. 选择学段（小学/初中/高中）
+3. 输入题目数量（1-100题）
+4. 进入答题界面
+5. 逐题作答，支持前后导航
+6. 提交试卷，查看成绩
+
+### 密码管理
+
+- **修改密码**：登录后可在用户中心修改
+- **重置密码**：登录页点击"忘记密码"，通过邮箱验证重置

src/main/java/com/example/myapp/Main.java

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+package com.example.myapp;
+
+import javafx.application.Application;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Parent;
+import javafx.scene.Scene;
+import javafx.stage.Stage;
+
+public class Main extends Application {
+  private static Stage primaryStage;
+
+  @Override
+  public void start(Stage stage) throws Exception{
+    primaryStage = stage;
+    showLogin();
+  }
+
+  public static void showLogin() throws Exception{
+    FXMLLoader loader = new FXMLLoader(Main.class.getResource("/fxml/login.fxml"));
+    primaryStage.setScene(new Scene(loader.load()));
+    primaryStage.setTitle("登录");
+    primaryStage.show();
+  }
+
+  public static void showRegister() throws Exception{
+    FXMLLoader loader = new FXMLLoader(Main.class.getResource("/fxml/register.fxml"));
+    primaryStage.setScene(new Scene(loader.load()));
+    primaryStage.setTitle("注册 - 输入邮箱");
+  }
+
+  public static void showSetPassword(String email) throws Exception{
+    FXMLLoader loader = new FXMLLoader(Main.class.getResource("/fxml/set_password.fxml"));
+    // 传递 email 给 controller
+    Parent root = loader.load();
+    var ctrl = loader.getController();
+    ((com.example.myapp.controller.SetPasswordController)ctrl).setEmail(email);
+    primaryStage.setScene(new Scene(root));
+    primaryStage.setTitle("设置密码");
+  }
+
+  public static void showDashboard(String email) throws Exception{
+    FXMLLoader loader = new FXMLLoader(Main.class.getResource("/fxml/dashboard.fxml"));
+    Parent root = loader.load();
+    var ctrl = loader.getController();
+    ((com.example.myapp.controller.DashboardController)ctrl).initUser(email);
+    primaryStage.setScene(new Scene(root));
+    primaryStage.setTitle("用户界面");
+  }
+
+  // 在 Main.java 中添加以下方法
+  public static void showGradeSelection(String email) throws Exception {
+    FXMLLoader loader = new FXMLLoader(Main.class.getResource("/fxml/grade_selection.fxml"));
+    Parent root = loader.load();
+    var ctrl = loader.getController();
+    ((com.example.myapp.controller.GradeSelectionController)ctrl).initUser(email);
+    primaryStage.setScene(new Scene(root));
+    primaryStage.setTitle("选择学段");
+  }
+
+  public static void showExamPage(String email) throws Exception {
+    FXMLLoader loader = new FXMLLoader(Main.class.getResource("/fxml/exam.fxml"));
+    Parent root = loader.load();
+
+    // 获取控制器并初始化
+    var ctrl = loader.getController();
+    ((com.example.myapp.controller.ExamController)ctrl).initExam(email);
+
+    primaryStage.setScene(new Scene(root));
+    primaryStage.setTitle("答题界面");
+  }
+
+  public static void showScorePage(String email, int score) throws Exception {
+    FXMLLoader loader = new FXMLLoader(Main.class.getResource("/fxml/score.fxml"));
+    Parent root = loader.load();
+    var ctrl = loader.getController();
+    ((com.example.myapp.controller.ScoreController)ctrl).initScore(email, score);
+    primaryStage.setScene(new Scene(root));
+    primaryStage.setTitle("考试成绩");
+  }
+
+  public static void showChangePassword(String email) throws Exception {
+    FXMLLoader loader = new FXMLLoader(Main.class.getResource("/fxml/change_password.fxml"));
+    Parent root = loader.load();
+    var ctrl = loader.getController();
+    ((com.example.myapp.controller.ChangePasswordController)ctrl).initUser(email);
+    primaryStage.setScene(new Scene(root));
+    primaryStage.setTitle("修改密码");
+  }
+
+
+  // 在 Main.java 中添加
+  public static void showForgotPassword(String email) throws Exception {
+    FXMLLoader loader = new FXMLLoader(Main.class.getResource("/fxml/forgot_password.fxml"));
+    Parent root = loader.load();
+    var ctrl = loader.getController();
+    ((com.example.myapp.controller.ForgotPasswordController)ctrl).setEmail(email);
+    primaryStage.setScene(new Scene(root));
+    primaryStage.setTitle("忘记密码");
+  }
+  public static void main(String[] args){
+    launch(args);
+  }
+}

src/main/java/com/example/myapp/controller/ChangePasswordController.java

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+package com.example.myapp.controller;
+
+import com.example.myapp.Main;
+import com.example.myapp.service.UserService;
+import com.example.myapp.util.PasswordUtil;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+
+public class ChangePasswordController {
+  @FXML private Label userLabel;
+  @FXML private PasswordField oldPwd;
+  @FXML private PasswordField newPwd;
+  @FXML private PasswordField newPwdConfirm;
+  @FXML private Button changeBtn;
+  @FXML private Button backBtn;
+  @FXML private Button clearBtn;
+  @FXML private Label statusLabel;
+
+  private String email;
+  private final UserService userService = UserService.getInstance();
+
+  public void initUser(String email) {
+    this.email = email;
+    userLabel.setText("修改密码 - " + email);
+    clearFields();
+  }
+
+  @FXML
+  public void onChangePassword() {
+    String oldp = oldPwd.getText();
+    String np = newPwd.getText();
+    String np2 = newPwdConfirm.getText();
+
+    if (oldp.isEmpty() || np.isEmpty() || np2.isEmpty()) {
+      statusLabel.setText("请填写所有密码字段");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    if (!userService.checkPassword(email, oldp)) {
+      statusLabel.setText("原密码不正确");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+    if (!np.equals(np2)) {
+      statusLabel.setText("两次新密码不一致");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+    if (!PasswordUtil.validatePasswordRules(np)) {
+      statusLabel.setText("新密码不符合规则（6-10位，含大小写和数字）");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    userService.setPassword(email, PasswordUtil.hash(np));
+    statusLabel.setText("密码修改成功！");
+    statusLabel.setStyle("-fx-text-fill: green;");
+    clearFields();
+  }
+
+  @FXML
+  public void onBack() {
+    try {
+      Main.showDashboard(email);
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  @FXML
+  public void onClear() {
+    clearFields();
+    statusLabel.setText("");
+  }
+
+  private void clearFields() {
+    oldPwd.clear();
+    newPwd.clear();
+    newPwdConfirm.clear();
+  }
+}

src/main/java/com/example/myapp/controller/DashboardController.java

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+package com.example.myapp.controller;
+
+import com.example.myapp.Main;
+import com.example.myapp.service.UserService;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+
+public class DashboardController {
+  @FXML private Label welcomeLabel;
+  @FXML private Button changePasswordBtn;
+  @FXML private Button studyBtn;
+  @FXML private Button logoutBtn;
+
+  private String email;
+  private final UserService userService = UserService.getInstance();
+
+  public void initUser(String email){
+    this.email = email;
+    String displayName = userService.getDisplayName(email);
+    welcomeLabel.setText("欢迎: " + displayName);
+  }
+
+  @FXML
+  public void onChangePassword() {
+    try {
+      Main.showChangePassword(email);
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  @FXML
+  public void onStudy() {
+    try {
+      Main.showGradeSelection(email);
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  @FXML
+  public void onLogout() {
+    try {
+      Main.showLogin();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+}

src/main/java/com/example/myapp/controller/ExamController.java

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+package com.example.myapp.controller;
+
+import com.example.myapp.Main;
+import com.example.myapp.model.Exam;
+import com.example.myapp.model.Question;
+import com.example.myapp.service.ExamService;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+
+public class ExamController {
+  @FXML private Label questionNumberLabel;
+  @FXML private Label questionTextLabel;
+  @FXML private RadioButton optionARadio;
+  @FXML private RadioButton optionBRadio;
+  @FXML private RadioButton optionCRadio;
+  @FXML private RadioButton optionDRadio;
+  @FXML private Label optionALabel;
+  @FXML private Label optionBLabel;
+  @FXML private Label optionCLabel;
+  @FXML private Label optionDLabel;
+  @FXML private Button previousBtn;
+  @FXML private Button nextBtn;
+  @FXML private Button submitBtn;
+  @FXML private ProgressIndicator progressIndicator;
+
+  private String email;
+  private ExamService examService = ExamService.getInstance();
+  private int currentQuestionIndex = 0;
+  private ToggleGroup optionsToggleGroup;
+
+  // 添加初始化方法，使用 @FXML 注解确保在FXML加载后立即执行
+  @FXML
+  public void initialize() {
+    // 在这里初始化 ToggleGroup，确保在FXML加载完成后立即执行
+    this.optionsToggleGroup = new ToggleGroup();
+
+    optionARadio.setToggleGroup(optionsToggleGroup);
+    optionBRadio.setToggleGroup(optionsToggleGroup);
+    optionCRadio.setToggleGroup(optionsToggleGroup);
+    optionDRadio.setToggleGroup(optionsToggleGroup);
+
+    // 设置默认禁用状态
+    previousBtn.setDisable(true);
+    submitBtn.setDisable(true);
+  }
+
+  public void initExam(String email) {
+    this.email = email;
+
+    // 确保有考试数据
+    Exam exam = examService.getCurrentExam(email);
+    if (exam == null || exam.getQuestions().isEmpty()) {
+      showAlert("错误", "没有找到考试数据，请重新选择学段");
+      try {
+        Main.showGradeSelection(email);
+      } catch (Exception e) {
+        e.printStackTrace();
+      }
+      return;
+    }
+
+    loadQuestion(0);
+  }
+
+  @FXML
+  public void onPreviousQuestion() {
+    saveCurrentAnswer();
+    if (currentQuestionIndex > 0) {
+      loadQuestion(currentQuestionIndex - 1);
+    }
+  }
+
+  @FXML
+  public void onNextQuestion() {
+    saveCurrentAnswer();
+    Exam exam = examService.getCurrentExam(email);
+    if (currentQuestionIndex < exam.getQuestions().size() - 1) {
+      loadQuestion(currentQuestionIndex + 1);
+    }
+  }
+
+  @FXML
+  public void onSubmitExam() {
+    saveCurrentAnswer();
+
+    // 计算分数
+    int score = examService.calculateScore(email);
+
+    // 显示分数界面
+    try {
+      Main.showScorePage(email, score);
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  private void loadQuestion(int index) {
+    Exam exam = examService.getCurrentExam(email);
+    if (exam == null || index < 0 || index >= exam.getQuestions().size()) {
+      return;
+    }
+
+    currentQuestionIndex = index;
+    Question question = exam.getQuestions().get(index);
+
+    // 更新界面
+    questionNumberLabel.setText("第 " + (index + 1) + " 题 / 共 " + exam.getQuestions().size() + " 题");
+    questionTextLabel.setText(question.getQuestionText());
+    optionALabel.setText("A. " + question.getOptionA());
+    optionBLabel.setText("B. " + question.getOptionB());
+    optionCLabel.setText("C. " + question.getOptionC());
+    optionDLabel.setText("D. " + question.getOptionD());
+
+    // 清除选择
+    optionsToggleGroup.selectToggle(null);
+
+    // 恢复用户之前的选择
+    if (question.getUserAnswer() != null) {
+      switch (question.getUserAnswer()) {
+        case "A": optionARadio.setSelected(true); break;
+        case "B": optionBRadio.setSelected(true); break;
+        case "C": optionCRadio.setSelected(true); break;
+        case "D": optionDRadio.setSelected(true); break;
+      }
+    }
+
+    // 更新按钮状态
+    previousBtn.setDisable(index == 0);
+    nextBtn.setDisable(index == exam.getQuestions().size() - 1);
+    submitBtn.setDisable(index != exam.getQuestions().size() - 1);
+
+    // 更新进度
+    progressIndicator.setProgress((double) (index + 1) / exam.getQuestions().size());
+  }
+
+  private void saveCurrentAnswer() {
+    // 添加空值检查
+    if (optionsToggleGroup == null) {
+      return;
+    }
+
+    RadioButton selectedRadio = (RadioButton) optionsToggleGroup.getSelectedToggle();
+    if (selectedRadio != null) {
+      String answer = "";
+      if (selectedRadio == optionARadio) answer = "A";
+      else if (selectedRadio == optionBRadio) answer = "B";
+      else if (selectedRadio == optionCRadio) answer = "C";
+      else if (selectedRadio == optionDRadio) answer = "D";
+
+      examService.submitAnswer(email, currentQuestionIndex, answer);
+    }
+  }
+
+  private void showAlert(String title, String message) {
+    Alert alert = new Alert(Alert.AlertType.ERROR);
+    alert.setTitle(title);
+    alert.setHeaderText(null);
+    alert.setContentText(message);
+    alert.showAndWait();
+  }
+}

src/main/java/com/example/myapp/controller/ForgotPasswordController.java

@@ -0,0 +1,105 @@
+package com.example.myapp.controller;
+
+import com.example.myapp.Main;
+import com.example.myapp.service.EmailService;
+import com.example.myapp.service.UserService;
+import com.example.myapp.util.PasswordUtil;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+import java.util.Random;
+
+public class ForgotPasswordController {
+  @FXML private Label emailLabel;
+  @FXML private Button sendCodeBtn;
+  @FXML private TextField codeField;
+  @FXML private PasswordField newPasswordField;
+  @FXML private PasswordField confirmPasswordField;
+  @FXML private Button resetPasswordBtn;
+  @FXML private Button backToLoginBtn;
+  @FXML private Label statusLabel;
+
+  private String email;
+  private final UserService userService = UserService.getInstance();
+  private EmailService emailService;
+
+  public ForgotPasswordController() {
+    try {
+      emailService = new EmailService();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  public void setEmail(String email) {
+    this.email = email;
+    emailLabel.setText("重置密码 - " + email);
+  }
+
+  @FXML
+  public void onSendCode() {
+    String code = generateCode();
+    userService.createResetPasswordCode(email, code);
+    try {
+      emailService.sendRegistrationCode(email, code);
+      statusLabel.setText("验证码已发送到您的邮箱，请查收");
+      statusLabel.setStyle("-fx-text-fill: green;");
+    } catch (Exception e) {
+      e.printStackTrace();
+      statusLabel.setText("发送失败: " + e.getMessage());
+      statusLabel.setStyle("-fx-text-fill: red;");
+    }
+  }
+
+  @FXML
+  public void onResetPassword() {
+    String code = codeField.getText().trim();
+    String newPassword = newPasswordField.getText();
+    String confirmPassword = confirmPasswordField.getText();
+
+    if (!userService.verifyResetPasswordCode(email, code)) {
+      statusLabel.setText("验证码错误或已过期");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    if (!newPassword.equals(confirmPassword)) {
+      statusLabel.setText("两次输入的密码不一致");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    if (!PasswordUtil.validatePasswordRules(newPassword)) {
+      statusLabel.setText("密码不符合规则（6-10位，须含大写、小写和数字）");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    String hash = PasswordUtil.hash(newPassword);
+    userService.setPassword(email, hash);
+
+    statusLabel.setText("密码重置成功，请重新登录");
+    statusLabel.setStyle("-fx-text-fill: green;");
+
+    try {
+      Thread.sleep(2000);
+      Main.showLogin();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  @FXML
+  public void onBackToLogin() {
+    try {
+      Main.showLogin();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  private String generateCode() {
+    Random r = new Random();
+    int v = 100000 + r.nextInt(900000);
+    return String.valueOf(v);
+  }
+}

src/main/java/com/example/myapp/controller/GradeSelectionController.java

@@ -0,0 +1,92 @@
+package com.example.myapp.controller;
+
+import com.example.myapp.Main;
+import com.example.myapp.service.ExamService;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+
+public class GradeSelectionController {
+  @FXML private Label welcomeLabel;
+
+  private String email;
+  private final ExamService examService = ExamService.getInstance();
+
+  public void initUser(String email) {
+    this.email = email;
+    welcomeLabel.setText("欢迎 " + email + "，请选择学段");
+  }
+
+  @FXML
+  public void onPrimarySchoolSelected() {
+    showQuestionCountDialog("小学");
+  }
+
+  @FXML
+  public void onMiddleSchoolSelected() {
+    showQuestionCountDialog("初中");
+  }
+
+  @FXML
+  public void onHighSchoolSelected() {
+    showQuestionCountDialog("高中");
+  }
+
+  @FXML
+  public void onBackToLogin() {
+    try {
+      Main.showLogin();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  @FXML
+  public void onBackToDashboard() {
+    try {
+      Main.showDashboard(email);
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  private void showQuestionCountDialog(String gradeLevel) {
+    TextInputDialog dialog = new TextInputDialog("10");
+    dialog.setTitle("题目数量");
+    dialog.setHeaderText("选择" + gradeLevel + "题目");
+    dialog.setContentText("请输入题目数量(1-100):");
+
+    dialog.showAndWait().ifPresent(countStr -> {
+      try {
+        int questionCount = Integer.parseInt(countStr);
+        if (questionCount < 1 || questionCount > 100) {
+          showAlert("题目数量必须在1-100之间");
+          return;
+        }
+
+        boolean success = examService.generateExam(gradeLevel, questionCount, email);
+        if (success) {
+          // 修复：添加异常处理
+          try {
+            Main.showExamPage(email);
+          } catch (Exception e) {
+            e.printStackTrace();
+            showAlert("无法进入考试页面");
+          }
+        } else {
+          showAlert("生成试卷失败，请重试");
+        }
+
+      } catch (NumberFormatException e) {
+        showAlert("请输入有效的数字");
+      }
+    });
+  }
+
+  private void showAlert(String message) {
+    Alert alert = new Alert(Alert.AlertType.ERROR);
+    alert.setTitle("错误");
+    alert.setHeaderText(null);
+    alert.setContentText(message);
+    alert.showAndWait();
+  }
+}

src/main/java/com/example/myapp/controller/LoginController.java

@@ -0,0 +1,121 @@
+package com.example.myapp.controller;
+
+import com.example.myapp.Main;
+import com.example.myapp.service.UserService;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+
+public class LoginController {
+  @FXML private TextField identifierField;  // 修改：改为identifier
+  @FXML private PasswordField passwordField;
+  @FXML private Button loginBtn;
+  @FXML private Button registerBtn;
+  @FXML private Button forgotPasswordBtn;
+  @FXML private Label statusLabel;
+
+  private final UserService userService = UserService.getInstance();
+
+  @FXML
+  public void onLogin(){
+    String identifier = identifierField.getText().trim();
+    String pwd = passwordField.getText();
+
+    if(identifier.isEmpty() || pwd.isEmpty()){
+      statusLabel.setText("请输入用户名/邮箱和密码");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    if(!userService.userExists(identifier)){
+      statusLabel.setText("账号不存在，请先注册");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    // 获取用户邮箱（用于后续操作）
+    String email = identifier;
+    if (!identifier.contains("@")) {
+      // 如果是用户名登录，需要获取对应的邮箱
+      var user = userService.getUserByIdentifier(identifier);
+      if (user != null) {
+        email = user.getEmail();
+      }
+    }
+
+    if(!userService.isUserRegistered(email)){
+      statusLabel.setText("该账号未完成注册，请完成注册流程");
+      statusLabel.setStyle("-fx-text-fill: orange;");
+      return;
+    }
+
+    boolean ok = userService.checkPassword(identifier, pwd);
+    if(ok){
+      statusLabel.setText("登录成功");
+      statusLabel.setStyle("-fx-text-fill: green;");
+      try {
+        Main.showDashboard(email);
+      } catch(Exception e){
+        e.printStackTrace();
+      }
+    } else {
+      statusLabel.setText("密码错误");
+      statusLabel.setStyle("-fx-text-fill: red;");
+    }
+  }
+
+  @FXML
+  public void onRegister(){
+    try {
+      Main.showRegister();
+    } catch(Exception e){
+      e.printStackTrace();
+    }
+  }
+
+  @FXML
+  public void onForgotPassword() {
+    String identifier = identifierField.getText().trim();
+
+    if (identifier.isEmpty()) {
+      statusLabel.setText("请输入用户名/邮箱");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    if (!userService.userExists(identifier)) {
+      statusLabel.setText("该账号未注册，请先注册");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    // 获取用户邮箱
+    String email = identifier;
+    if (!identifier.contains("@")) {
+      var user = userService.getUserByIdentifier(identifier);
+      if (user != null) {
+        email = user.getEmail();
+      }
+    }
+
+    if (!userService.isUserRegistered(email)) {
+      statusLabel.setText("该账号未完成注册，请先完成注册");
+      statusLabel.setStyle("-fx-text-fill: orange;");
+      return;
+    }
+
+    try {
+      Main.showForgotPassword(email);
+    } catch (Exception e) {
+      e.printStackTrace();
+      statusLabel.setText("系统错误: " + e.getMessage());
+      statusLabel.setStyle("-fx-text-fill: red;");
+    }
+  }
+
+  @FXML
+  public void onClear() {
+    identifierField.clear();
+    passwordField.clear();
+    statusLabel.setText("");
+  }
+}

src/main/java/com/example/myapp/controller/RegisterController.java

@@ -0,0 +1,142 @@
+package com.example.myapp.controller;
+
+import com.example.myapp.Main;
+import com.example.myapp.service.EmailService;
+import com.example.myapp.service.UserService;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+
+import java.util.Random;
+
+public class RegisterController {
+  @FXML private TextField emailField;
+  @FXML private Button sendCodeBtn;
+  @FXML private TextField codeField;
+  @FXML private Button verifyBtn;
+  @FXML private Label statusLabel;
+
+  private final UserService userService = UserService.getInstance();
+  private EmailService emailService;
+
+  public RegisterController(){
+    try {
+      emailService = new EmailService();
+    } catch(Exception e){
+      e.printStackTrace();
+    }
+  }
+
+  @FXML
+  public void onSendCode(){
+    String email = emailField.getText().trim();
+
+    // 验证邮箱格式
+    if(email.isEmpty()){
+      statusLabel.setText("请输入邮箱地址");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    if(!isValidEmail(email)){
+      statusLabel.setText("请输入有效的邮箱地址");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    // 检查邮箱是否已被注册
+    if(userService.emailExists(email)){
+      // 检查用户是否已完成注册（设置了密码）
+      if(userService.isUserRegistered(email)){
+        statusLabel.setText("该邮箱已被注册，请直接登录");
+        statusLabel.setStyle("-fx-text-fill: red;");
+        return;
+      } else {
+        // 用户已存在但未完成注册，可以重新发送验证码
+        statusLabel.setText("该邮箱正在注册流程中，重新发送验证码");
+        statusLabel.setStyle("-fx-text-fill: orange;");
+      }
+    }
+
+    String code = generateCode();
+    userService.createPendingUser(email, code);
+    try{
+      emailService.sendRegistrationCode(email, code);
+      statusLabel.setText("注册码已发送到您的邮箱，请查收");
+      statusLabel.setStyle("-fx-text-fill: green;");
+
+      // 禁用发送按钮一段时间，防止重复发送
+      disableSendButtonTemporarily();
+
+    }catch(Exception e){
+      e.printStackTrace();
+      statusLabel.setText("发送失败: " + e.getMessage());
+      statusLabel.setStyle("-fx-text-fill: red;");
+    }
+  }
+
+  private String generateCode(){
+    Random r = new Random();
+    int v = 100000 + r.nextInt(900000);
+    return String.valueOf(v);
+  }
+
+  @FXML
+  public void onVerify(){
+    String email = emailField.getText().trim();
+    String code = codeField.getText().trim();
+
+    if(email.isEmpty() || code.isEmpty()){
+      statusLabel.setText("请输入邮箱和验证码");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    if(userService.verifyCode(email, code)){
+      statusLabel.setText("验证通过，请设置密码");
+      statusLabel.setStyle("-fx-text-fill: green;");
+      try {
+        Main.showSetPassword(email);
+      } catch(Exception e){
+        e.printStackTrace();
+      }
+    } else {
+      statusLabel.setText("注册码错误或已过期");
+      statusLabel.setStyle("-fx-text-fill: red;");
+    }
+  }
+  @FXML
+  public void onClear() {
+    emailField.clear();
+    codeField.clear();
+    statusLabel.setText("");
+    sendCodeBtn.setDisable(false);
+  }
+  @FXML
+  public void onBackToLogin() {
+    try {
+      Main.showLogin();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  private boolean isValidEmail(String email) {
+    String emailRegex = "^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$";
+    return email.matches(emailRegex);
+  }
+
+  private void disableSendButtonTemporarily() {
+    sendCodeBtn.setDisable(true);
+    new java.util.Timer().schedule(
+            new java.util.TimerTask() {
+              @Override
+              public void run() {
+                javafx.application.Platform.runLater(() -> {
+                  sendCodeBtn.setDisable(false);
+                });
+              }
+            },
+            60000 // 60秒后才能重新发送
+    );
+  }
+}

src/main/java/com/example/myapp/controller/ScoreController.java

@@ -0,0 +1,65 @@
+package com.example.myapp.controller;
+
+import com.example.myapp.Main;
+import com.example.myapp.service.ExamService;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+
+public class ScoreController {
+  @FXML private Label scoreLabel;
+  @FXML private Label commentLabel;
+  @FXML private Button continueBtn;
+  @FXML private Button exitBtn;
+
+  private String email;
+  private int score;
+  private ExamService examService = ExamService.getInstance();
+
+  public void initScore(String email, int score) {
+    this.email = email;
+    this.score = score;
+
+    scoreLabel.setText("得分: " + score + " 分");
+
+    // 根据分数给出评价
+    if (score >= 90) {
+      commentLabel.setText("优秀！表现非常出色！");
+      commentLabel.setStyle("-fx-text-fill: #27ae60;");
+    } else if (score >= 80) {
+      commentLabel.setText("良好！继续努力！");
+      commentLabel.setStyle("-fx-text-fill: #2980b9;");
+    } else if (score >= 60) {
+      commentLabel.setText("及格！还有提升空间！");
+      commentLabel.setStyle("-fx-text-fill: #f39c12;");
+    } else {
+      commentLabel.setText("不及格！需要加强学习！");
+      commentLabel.setStyle("-fx-text-fill: #e74c3c;");
+    }
+  }
+
+  @FXML
+  public void onContinue() {
+    // 清除当前考试数据
+    examService.clearExam(email);
+
+    // 返回选择界面
+    try {
+      Main.showGradeSelection(email);
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  @FXML
+  public void onExit() {
+    // 清除考试数据
+    examService.clearExam(email);
+
+    // 返回登录界面
+    try {
+      Main.showLogin();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+}

src/main/java/com/example/myapp/controller/SetPasswordController.java

@@ -0,0 +1,83 @@
+package com.example.myapp.controller;
+
+import com.example.myapp.Main;
+import com.example.myapp.service.UserService;
+import com.example.myapp.util.PasswordUtil;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+
+public class SetPasswordController {
+  @FXML private Label emailLabel;
+  @FXML private TextField usernameField;
+  @FXML private PasswordField pwdField;
+  @FXML private PasswordField pwdConfirmField;
+  @FXML private Button setBtn;
+  @FXML private Label statusLabel;
+
+  private String email;
+  private final UserService userService = UserService.getInstance();
+
+  public void setEmail(String email){
+    this.email = email;
+    emailLabel.setText("设置账号信息 - " + email);
+  }
+
+  @FXML
+  public void onSetPassword(){
+    String username = usernameField.getText().trim();
+    String p1 = pwdField.getText();
+    String p2 = pwdConfirmField.getText();
+
+    // 验证用户名
+    if (username.isEmpty()) {
+      statusLabel.setText("请输入用户名");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    if (username.length() < 2 || username.length() > 20) {
+      statusLabel.setText("用户名长度应为2-20个字符");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    // 检查用户名是否已存在
+    if (userService.usernameExists(username)) {
+      statusLabel.setText("用户名已存在，请选择其他用户名");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    // 验证密码
+    if(!p1.equals(p2)){
+      statusLabel.setText("两次密码不一致");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    if(!PasswordUtil.validatePasswordRules(p1)){
+      statusLabel.setText("密码不符合规则（6-10位，须含大写、小写和数字）");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    // 设置用户名和密码
+    boolean usernameSet = userService.setUsername(email, username);
+    if (!usernameSet) {
+      statusLabel.setText("设置用户名失败");
+      statusLabel.setStyle("-fx-text-fill: red;");
+      return;
+    }
+
+    String hash = PasswordUtil.hash(p1);
+    userService.setPassword(email, hash);
+    statusLabel.setText("注册成功！即将进入用户中心");
+    statusLabel.setStyle("-fx-text-fill: green;");
+
+    try {
+      Main.showDashboard(email);
+    } catch(Exception e){
+      e.printStackTrace();
+    }
+  }
+}

src/main/java/com/example/myapp/model/Exam.java

@@ -0,0 +1,40 @@
+package com.example.myapp.model;
+
+import java.util.List;
+import java.time.LocalDateTime;
+
+public class Exam {
+  private String gradeLevel;
+  private int questionCount;
+  private List<Question> questions;
+  private int score;
+  private LocalDateTime startTime;
+  private LocalDateTime endTime;
+
+  public Exam(String gradeLevel, int questionCount, List<Question> questions) {
+    this.gradeLevel = gradeLevel;
+    this.questionCount = questionCount;
+    this.questions = questions;
+    this.startTime = LocalDateTime.now();
+    this.score = -1; // -1表示未评分
+  }
+
+  // Getters and Setters
+  public String getGradeLevel() { return gradeLevel; }
+  public void setGradeLevel(String gradeLevel) { this.gradeLevel = gradeLevel; }
+
+  public int getQuestionCount() { return questionCount; }
+  public void setQuestionCount(int questionCount) { this.questionCount = questionCount; }
+
+  public List<Question> getQuestions() { return questions; }
+  public void setQuestions(List<Question> questions) { this.questions = questions; }
+
+  public int getScore() { return score; }
+  public void setScore(int score) { this.score = score; }
+
+  public LocalDateTime getStartTime() { return startTime; }
+  public void setStartTime(LocalDateTime startTime) { this.startTime = startTime; }
+
+  public LocalDateTime getEndTime() { return endTime; }
+  public void setEndTime(LocalDateTime endTime) { this.endTime = endTime; }
+}

src/main/java/com/example/myapp/model/Expression.java

@@ -0,0 +1,14 @@
+// Expression.java
+package com.example.myapp.model;
+
+public class Expression {
+  public String expression;
+  public double value;  // 改为 double 类型支持小数答案
+  public String mainOperator;
+
+  public Expression(String expression, double value, String mainOperator) {
+    this.expression = expression;
+    this.value = value;
+    this.mainOperator = mainOperator;
+  }
+}

src/main/java/com/example/myapp/model/Question.java

@@ -0,0 +1,52 @@
+package com.example.myapp.model;
+
+public class Question {
+  private String questionText;
+  private String optionA;
+  private String optionB;
+  private String optionC;
+  private String optionD;
+  private String correctAnswer;
+  private String userAnswer;
+
+//  public Question(String questionText, String optionA, String optionB,
+//                  String optionC, String optionD, String correctAnswer) {
+//    this.questionText = questionText;
+//    this.optionA = optionA;
+//    this.optionB = optionB;
+//    this.optionC = optionC;
+//    this.optionD = optionD;
+//    this.correctAnswer = correctAnswer;
+//  }
+
+  // Getters and Setters
+  public Question(String questionText, String optionA, String optionB,
+                  String optionC, String optionD, String correctAnswer) {
+    this.questionText = questionText;
+    this.optionA = optionA;
+    this.optionB = optionB;
+    this.optionC = optionC;
+    this.optionD = optionD;
+    this.correctAnswer = correctAnswer;
+  }
+  public String getQuestionText() { return questionText; }
+  public void setQuestionText(String questionText) { this.questionText = questionText; }
+
+  public String getOptionA() { return optionA; }
+  public void setOptionA(String optionA) { this.optionA = optionA; }
+
+  public String getOptionB() { return optionB; }
+  public void setOptionB(String optionB) { this.optionB = optionB; }
+
+  public String getOptionC() { return optionC; }
+  public void setOptionC(String optionC) { this.optionC = optionC; }
+
+  public String getOptionD() { return optionD; }
+  public void setOptionD(String optionD) { this.optionD = optionD; }
+
+  public String getCorrectAnswer() { return correctAnswer; }
+  public void setCorrectAnswer(String correctAnswer) { this.correctAnswer = correctAnswer; }
+
+  public String getUserAnswer() { return userAnswer; }
+  public void setUserAnswer(String userAnswer) { this.userAnswer = userAnswer; }
+}

src/main/java/com/example/myapp/model/User.java

@@ -0,0 +1,62 @@
+package com.example.myapp.model;
+
+import java.io.Serializable;
+import java.time.LocalDateTime;
+
+public class User implements Serializable {
+  private String email;
+  private String username;  // 新增用户名字段
+  private String passwordHash;
+  private boolean verified;
+  private LocalDateTime createdAt;
+  private LocalDateTime lastModified;
+
+  public User() {
+    this.createdAt = LocalDateTime.now();
+    this.lastModified = LocalDateTime.now();
+  }
+
+  public User(String email, String username) {
+    this.email = email;
+    this.username = username;
+    this.verified = false;
+    this.createdAt = LocalDateTime.now();
+    this.lastModified = LocalDateTime.now();
+  }
+
+  // Getters and Setters
+  public String getEmail() { return email; }
+  public void setEmail(String email) {
+    this.email = email;
+    this.lastModified = LocalDateTime.now();
+  }
+
+  public String getUsername() { return username; }
+  public void setUsername(String username) {
+    this.username = username;
+    this.lastModified = LocalDateTime.now();
+  }
+
+  public String getPasswordHash() { return passwordHash; }
+  public void setPasswordHash(String passwordHash) {
+    this.passwordHash = passwordHash;
+    this.lastModified = LocalDateTime.now();
+  }
+
+  public boolean isVerified() { return verified; }
+  public void setVerified(boolean verified) {
+    this.verified = verified;
+    this.lastModified = LocalDateTime.now();
+  }
+
+  public LocalDateTime getCreatedAt() { return createdAt; }
+  public void setCreatedAt(LocalDateTime createdAt) { this.createdAt = createdAt; }
+
+  public LocalDateTime getLastModified() { return lastModified; }
+  public void setLastModified(LocalDateTime lastModified) { this.lastModified = lastModified; }
+
+  @Override
+  public String toString() {
+    return "User{email='" + email + "', username='" + username + "', verified=" + verified + "}";
+  }
+}

src/main/java/com/example/myapp/service/AbstractQuestionSeting.java

@@ -0,0 +1,80 @@
+// AbstractQuestionSeting.java
+package com.example.myapp.service;
+
+import com.example.myapp.model.Expression;
+import java.util.Random;
+
+public abstract class AbstractQuestionSeting implements QuestionSeting {
+  protected Random rand = new Random();
+
+  // 只生成整数（1-50）
+  protected String getRandomNumber() {
+    int num = 1 + rand.nextInt(50);
+    return String.valueOf(num);
+  }
+
+  // 生成完全平方数（用于开方运算）
+  protected String getPerfectSquare() {
+    int base = 1 + rand.nextInt(12); // 1-12的平方
+    int square = base * base;
+    return String.valueOf(square);
+  }
+
+  // 生成适合开方的数（完全平方数）
+  protected String getNumberForSqrt() {
+    // 80%概率生成完全平方数，20%概率生成普通数
+    //if (rand.nextDouble() < 1) {
+      return getPerfectSquare();
+//    } else {
+//      return getRandomNumber();
+//    }
+  }
+
+  protected String getRandomOperator() {
+    String[] ops = {"+", "-", "*", "/"};
+    return ops[rand.nextInt(ops.length)];
+  }
+
+  protected int getPriority(String op) {
+    if (op == null) return 3;
+    switch (op) {
+      case "+":
+      case "-":
+        return 1;
+      case "*":
+      case "/":
+        return 2;
+      case "²":
+      case "√":
+      case "sin":
+      case "cos":
+      case "tan":
+        return 3;
+      default:
+        return 0;
+    }
+  }
+
+  // 解析数字字符串为double
+  protected double parseNumber(String numStr) {
+    return Double.parseDouble(numStr);
+  }
+
+  // 格式化结果为字符串，如果是整数显示整数，小数显示小数
+  protected String formatResult(double value) {
+    if (value == (int) value) {
+      return String.valueOf((int) value);
+    } else {
+      // 保留2位小数，但去除末尾的0
+      String formatted = String.format("%.2f", value);
+      if (formatted.endsWith(".00")) {
+        return formatted.substring(0, formatted.length() - 3);
+      } else if (formatted.endsWith("0")) {
+        return formatted.substring(0, formatted.length() - 1);
+      }
+      return formatted;
+    }
+  }
+
+  public abstract String addParenthesesIfNeeded(Expression child, String parentOp, boolean isRightChild);
+}

src/main/java/com/example/myapp/service/EmailService.java

@@ -0,0 +1,46 @@
+package com.example.myapp.service;
+
+import jakarta.mail.*;
+import jakarta.mail.internet.*;
+import java.io.InputStream;
+import java.util.Properties;
+
+public class EmailService {
+  private final Properties props = new Properties();
+  private final String username;
+  private final String password;
+  private final String from;
+
+  public EmailService() throws Exception{
+    try(InputStream is = getClass().getResourceAsStream("/app.properties")){
+      Properties p = new Properties();
+      p.load(is);
+      String host = p.getProperty("smtp.host");
+      String port = p.getProperty("smtp.port");
+      username = p.getProperty("smtp.username");
+      password = p.getProperty("smtp.password");
+      from = p.getProperty("smtp.from");
+
+      props.put("mail.smtp.auth", "true");
+      props.put("mail.smtp.starttls.enable", "true");
+      props.put("mail.smtp.host", host);
+      props.put("mail.smtp.port", port);
+    }
+  }
+
+  public void sendRegistrationCode(String toEmail, String code) throws MessagingException {
+    Session session = Session.getInstance(props, new Authenticator(){
+      protected PasswordAuthentication getPasswordAuthentication(){
+        return new PasswordAuthentication(username, password);
+      }
+    });
+
+    Message message = new MimeMessage(session);
+    message.setFrom(new InternetAddress(from));
+    message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(toEmail));
+    message.setSubject("你的注册码");
+    message.setText("你的注册码是: " + code + "\n\n请输入此注册码完成注册。");
+
+    Transport.send(message);
+  }
+}

src/main/java/com/example/myapp/service/ExamService.java

@@ -0,0 +1,90 @@
+// ExamService.java
+package com.example.myapp.service;
+
+import com.example.myapp.model.Exam;
+import com.example.myapp.model.Question;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.Map;
+
+public class ExamService {
+  private Map<String, Exam> userExams = new ConcurrentHashMap<>();
+  private static final ExamService instance = new ExamService();
+
+  public static ExamService getInstance() {
+    return instance;
+  }
+
+  public boolean generateExam(String gradeLevel, int questionCount, String email) {
+    try {
+      List<Question> questions = MathQuestionGenerator.generateQuestions(gradeLevel, questionCount);
+      Exam exam = new Exam(gradeLevel, questionCount, questions);
+      userExams.put(email, exam);
+      return true;
+    } catch (Exception e) {
+      e.printStackTrace();
+      return false;
+    }
+  }
+
+  public Exam getCurrentExam(String email) {
+    return userExams.get(email);
+  }
+
+  public boolean submitAnswer(String email, int questionIndex, String selectedAnswer) {
+    Exam exam = userExams.get(email);
+    if (exam != null && questionIndex >= 0 && questionIndex < exam.getQuestions().size()) {
+      exam.getQuestions().get(questionIndex).setUserAnswer(selectedAnswer);
+      return true;
+    }
+    return false;
+  }
+
+  // 在 ExamService.java 的 calculateScore 方法中修改答案比较逻辑
+  public int calculateScore(String email) {
+    Exam exam = userExams.get(email);
+    if (exam == null) return 0;
+
+    int correctCount = 0;
+    for (Question question : exam.getQuestions()) {
+      String userAnswer = question.getUserAnswer();
+      String correctAnswer = question.getCorrectAnswer();
+
+      // 使用容差比较答案（针对小数）
+      if (isAnswerCorrect(userAnswer, correctAnswer)) {
+        correctCount++;
+      }
+    }
+
+    int score = (int) ((correctCount * 100.0) / exam.getQuestions().size());
+    exam.setScore(score);
+    return score;
+  }
+
+  // 新增答案比较方法，支持小数容差
+  private boolean isAnswerCorrect(String userAnswer, String correctAnswer) {
+    if (userAnswer == null || correctAnswer == null) {
+      return false;
+    }
+
+    try {
+      // 去除选项标签（如"A. "）
+      String cleanUserAnswer = userAnswer.replaceAll("^[A-D]\\.\\s*", "");
+      String cleanCorrectAnswer = correctAnswer.replaceAll("^[A-D]\\.\\s*", "");
+
+      // 尝试解析为数字进行比较
+      double userValue = Double.parseDouble(cleanUserAnswer);
+      double correctValue = Double.parseDouble(cleanCorrectAnswer);
+
+      // 使用容差比较
+      return Math.abs(userValue - correctValue) < 0.01;
+    } catch (NumberFormatException e) {
+      // 如果无法解析为数字，进行字符串比较
+      return userAnswer.trim().equals(correctAnswer.trim());
+    }
+  }
+
+  public void clearExam(String email) {
+    userExams.remove(email);
+  }
+}

src/main/java/com/example/myapp/service/FileStorageService.java

@@ -0,0 +1,104 @@
+package com.example.myapp.service;
+
+import com.example.myapp.model.User;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class FileStorageService {
+  private static final String DATA_DIR = "data";
+  private static final String USERS_FILE = DATA_DIR + "/users.json";
+  private static final String REGISTRATION_CODES_FILE = DATA_DIR + "/registration_codes.json";
+  private static final String RESET_PASSWORD_CODES_FILE = DATA_DIR + "/reset_password_codes.json";
+
+  private final ObjectMapper objectMapper;
+
+  public FileStorageService() {
+    this.objectMapper = new ObjectMapper();
+    objectMapper.registerModule(new JavaTimeModule());
+    objectMapper.enable(SerializationFeature.INDENT_OUTPUT);
+    objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
+
+    try {
+      Files.createDirectories(Paths.get(DATA_DIR));
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+  }
+
+  // 读取用户数据
+  public Map<String, User> readUsersData() {
+    try {
+      File file = new File(USERS_FILE);
+      if (!file.exists()) {
+        return new ConcurrentHashMap<>();
+      }
+      return objectMapper.readValue(file, new TypeReference<ConcurrentHashMap<String, User>>() {});
+    } catch (Exception e) {
+      e.printStackTrace();
+      return new ConcurrentHashMap<>();
+    }
+  }
+
+  // 读取注册码数据
+  public Map<String, String> readRegistrationCodesData() {
+    try {
+      File file = new File(REGISTRATION_CODES_FILE);
+      if (!file.exists()) {
+        return new ConcurrentHashMap<>();
+      }
+      return objectMapper.readValue(file, new TypeReference<ConcurrentHashMap<String, String>>() {});
+    } catch (Exception e) {
+      e.printStackTrace();
+      return new ConcurrentHashMap<>();
+    }
+  }
+
+  // 新增：读取重置密码码数据
+  public Map<String, String> readResetPasswordCodesData() {
+    try {
+      File file = new File(RESET_PASSWORD_CODES_FILE);
+      if (!file.exists()) {
+        return new ConcurrentHashMap<>();
+      }
+      return objectMapper.readValue(file, new TypeReference<ConcurrentHashMap<String, String>>() {});
+    } catch (Exception e) {
+      e.printStackTrace();
+      return new ConcurrentHashMap<>();
+    }
+  }
+
+  // 写入用户数据
+  public void writeUsersData(Map<String, User> data) {
+    try {
+      objectMapper.writeValue(new File(USERS_FILE), data);
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+  }
+
+  // 写入注册码数据
+  public void writeRegistrationCodesData(Map<String, String> data) {
+    try {
+      objectMapper.writeValue(new File(REGISTRATION_CODES_FILE), data);
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+  }
+
+  // 新增：写入重置密码码数据
+  public void writeResetPasswordCodesData(Map<String, String> data) {
+    try {
+      objectMapper.writeValue(new File(RESET_PASSWORD_CODES_FILE), data);
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+  }
+}

src/main/java/com/example/myapp/service/HighQueSeting.java

@@ -0,0 +1,139 @@
+// HighQueSeting.java
+package com.example.myapp.service;
+
+import com.example.myapp.model.Expression;
+
+public class HighQueSeting extends AbstractQuestionSeting {
+
+  @Override
+  public String addParenthesesIfNeeded(Expression child, String parentOp, boolean isRightChild) {
+    if (child.mainOperator == null
+        || child.mainOperator.equals("²") || child.mainOperator.equals("√")
+        || child.mainOperator.equals("sin") || child.mainOperator.equals("cos")
+        || child.mainOperator.equals("tan")) {
+      return child.expression;
+    }
+
+    int parentPriority = getPriority(parentOp);
+    int childPriority = getPriority(child.mainOperator);
+
+    if (childPriority < parentPriority) {
+      return "(" + child.expression + ")";
+    }
+
+    if (isRightChild && (parentOp.equals("-") || parentOp.equals("/"))) {
+      if (parentPriority == childPriority) {
+        return "(" + child.expression + ")";
+      }
+    }
+
+    return child.expression;
+  }
+
+  public Expression applyUnary(Expression child, String op) {
+    switch (op) {
+      case "²":
+        if (child.mainOperator == null) {
+          return new Expression(child.expression + "²", child.value * child.value, "²");
+        }
+        return new Expression("(" + child.expression + ")²", child.value * child.value, "²");
+      case "√":
+        String numStr = getNumberForSqrt();
+        child = new Expression(numStr, parseNumber(numStr), null);
+
+        double sqrtValue = Math.sqrt(child.value);
+        if (child.mainOperator == null) {
+          return new Expression("√" + child.expression, sqrtValue, "√");
+        }
+        return new Expression("√(" + child.expression + ")", sqrtValue, "√");
+      case "sin":
+        int[] sinAngles = {0, 30, 45, 60, 90, 120, 135, 150, 180};
+        int sinAngle = sinAngles[rand.nextInt(sinAngles.length)];
+        child = new Expression(String.valueOf(sinAngle), sinAngle, null);
+        return new Expression("sin(" + child.expression + "°)",
+            Math.sin(Math.toRadians(child.value)), "sin");
+      case "cos":
+        int[] cosAngles = {0, 30, 45, 60, 90, 120, 135, 150, 180};
+        int cosAngle = cosAngles[rand.nextInt(cosAngles.length)];
+        child = new Expression(String.valueOf(cosAngle), cosAngle, null);
+        return new Expression("cos(" + child.expression + "°)",
+            Math.cos(Math.toRadians(child.value)), "cos");
+      case "tan":
+        int[] tanAngles = {0, 30, 45, 60, 120, 135, 150, 180};
+        int tanAngle = tanAngles[rand.nextInt(tanAngles.length)];
+        child = new Expression(String.valueOf(tanAngle), tanAngle, null);
+        double tanValue = Math.tan(Math.toRadians(child.value));
+        if (Math.abs(tanValue) > 1000) {
+          tanValue = tanValue > 0 ? 1000 : -1000;
+        }
+        return new Expression("tan(" + child.expression + "°)", tanValue, "tan");
+      default:
+        return child;
+    }
+  }
+
+  @Override
+  public Expression setQuestion(int count) {
+    Expression result = firstSetQuestion(count);
+    // 确保高中题目包含至少一个三角函数
+    int attempts = 0;
+    while (!result.expression.contains("sin") && !result.expression.contains("cos")
+        && !result.expression.contains("tan") && attempts < 10) {
+      result = firstSetQuestion(count);
+      attempts++;
+    }
+    return result;
+  }
+
+  public Expression probability(Expression result) {
+    // 高中阶段：40%概率添加一元运算
+    if (rand.nextDouble() < 0.4) {
+      String[] unaryOps = {"²", "√", "sin", "cos", "tan"};
+      String unaryOp = unaryOps[rand.nextInt(unaryOps.length)];
+      result = applyUnary(result, unaryOp);
+      result.mainOperator = unaryOp;
+    }
+    return result;
+  }
+
+  public Expression firstSetQuestion(int count) {
+    if (count == 1) {
+      String numStr = getRandomNumber();
+      Expression expr = new Expression(numStr, parseNumber(numStr), null);
+      expr = probability(expr);
+      return expr;
+    }
+    int leftCount = 1 + rand.nextInt(count - 1);
+    int rightCount = count - leftCount;
+
+    Expression left = firstSetQuestion(leftCount);
+    Expression right = firstSetQuestion(rightCount);
+
+    String op = getRandomOperator();
+    double value = 0;
+    switch (op) {
+      case "+":
+        value = left.value + right.value;
+        break;
+      case "-":
+        value = left.value - right.value;
+        break;
+      case "*":
+        value = left.value * right.value;
+        break;
+      case "/":
+        if (Math.abs(right.value) < 1e-10) {
+          return firstSetQuestion(count);
+        }
+        value = left.value / right.value;
+        break;
+    }
+
+    String leftExpr = addParenthesesIfNeeded(left, op, false);
+    String rightExpr = addParenthesesIfNeeded(right, op, true);
+
+    Expression result = new Expression(leftExpr + " " + op + " " + rightExpr, value, op);
+    result = probability(result);
+    return result;
+  }
+}

src/main/java/com/example/myapp/service/MathQuestionGenerator.java

@@ -0,0 +1,139 @@
+// MathQuestionGenerator.java
+package com.example.myapp.service;
+
+import com.example.myapp.model.Question;
+import com.example.myapp.model.Expression;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+public class MathQuestionGenerator {
+  private static final Random random = new Random();
+
+  public static List<Question> generateQuestions(String gradeLevel, int count) {
+    List<Question> questions = new ArrayList<>();
+    QueSetingFactory factory = new QueSetingFactory();
+    QuestionSeting questionSeting = factory.getQueSeting(gradeLevel);
+    Set<String> generatedExpressions = new HashSet<>();
+    int maxAttempts = count * 3; // 最大尝试次数，防止无限循环
+    for (int i = 0; i < count; i++) {
+      boolean questionGenerated = false;
+      int attempts = 0;
+      while (!questionGenerated && attempts < maxAttempts) {
+        try {
+          int nodeCount = 2 + random.nextInt(3);
+          Expression expression = questionSeting.setQuestion(nodeCount);
+          if (generatedExpressions.contains(expression.expression)) {
+            attempts++;
+            continue; // 如果重复，重新生成
+          }
+          String correctAnswer = formatValue(expression.value);
+          String questionText = "计算: " + expression.expression + " = ?";
+          List<String> options = generateOptions(expression.value);
+          Question question = new Question(
+                  questionText, options.get(0),  // A
+                  options.get(1),  // B
+                  options.get(2),  // C
+                  options.get(3),  // D
+                  getCorrectAnswerLabel(options, correctAnswer)  // 正确答案标签
+          );
+          questions.add(question);
+          generatedExpressions.add(expression.expression); // 记录已生成的题目
+          questionGenerated = true;
+        } catch (Exception e) {
+          System.err.println("生成题目失败: " + e.getMessage());
+          attempts++;
+        }
+      }
+      if (!questionGenerated) {
+        questions.add(createFallbackQuestion(i, generatedExpressions));
+      }
+    }
+    return questions;
+  }
+
+  // 格式化数值，整数显示整数，小数显示小数（去除末尾的0）
+  private static String formatValue(double value) {
+    if (value == (int) value) {
+      return String.valueOf((int) value);
+    } else {
+      // 保留2位小数，但去除末尾的0
+      String formatted = String.format("%.2f", value);
+      if (formatted.endsWith(".00")) {
+        return formatted.substring(0, formatted.length() - 3);
+      } else if (formatted.endsWith("0")) {
+        return formatted.substring(0, formatted.length() - 1);
+      }
+      return formatted;
+    }
+  }
+
+  private static List<String> generateOptions(double correctValue) {
+    List<String> options = new ArrayList<>();
+    String correctAnswerStr = formatValue(correctValue);
+    options.add(correctAnswerStr);  // 正确答案
+
+    // 生成3个错误答案
+    while (options.size() < 4) {
+      double deviation;
+      // 根据正确答案的大小调整偏差
+      if (Math.abs(correctValue) < 10) {
+        // 小数值使用较小的偏差
+        deviation = 0.5 + random.nextDouble() * 3.0;
+      } else {
+        // 大数值使用较大的偏差
+        deviation = 1 + random.nextInt(5);
+      }
+
+      boolean positive = random.nextBoolean();
+      double wrongValue = positive ? correctValue + deviation : correctValue - deviation;
+
+      // 确保错误答案合理且与正确答案不同
+      String wrongValueStr = formatValue(wrongValue);
+      if (!options.contains(wrongValueStr)) {
+        options.add(wrongValueStr);
+      }
+    }
+
+    Collections.shuffle(options);
+    return options;
+  }
+
+  private static String getCorrectAnswerLabel(List<String> options, String correctAnswer) {
+    for (int i = 0; i < options.size(); i++) {
+      if (options.get(i).equals(correctAnswer)) {
+        return String.valueOf((char)('A' + i));
+      }
+    }
+    return "D";
+  }
+
+  // 修改备用题目生成方法，也避免重复
+  private static Question createFallbackQuestion(int index, Set<String> generatedExpressions) {
+    int baseNum = index + 1;
+    String expression;
+
+    // 尝试生成不重复的简单表达式
+    if (!generatedExpressions.contains(baseNum + " + " + (baseNum + 1))) {
+      expression = baseNum + " + " + (baseNum + 1);
+    } else if (!generatedExpressions.contains(baseNum + " × " + (baseNum + 2))) {
+      expression = baseNum + " × " + (baseNum + 2);
+    } else {
+      expression = (baseNum + 5) + " - " + baseNum;
+    }
+
+    generatedExpressions.add(expression);
+
+    return new Question(
+            "计算: " + expression + " = ?",
+            "A. " + (2 * baseNum + 1),
+            "B. " + (2 * baseNum + 2),
+            "C. " + (2 * baseNum + 3),
+            "D. " + (2 * baseNum + 4),
+            "C"
+    );
+  }
+}

src/main/java/com/example/myapp/service/MiddleQueSeting.java

@@ -0,0 +1,113 @@
+// MiddleQueSeting.java
+package com.example.myapp.service;
+
+import com.example.myapp.model.Expression;
+
+public class MiddleQueSeting extends AbstractQuestionSeting {
+
+  public Expression applyUnary(Expression child, String op) {
+    switch (op) {
+      case "²":
+        if (child.mainOperator == null) {
+          return new Expression(child.expression + "²", child.value * child.value, "²");
+        }
+        return new Expression("(" + child.expression + ")²", child.value * child.value, "²");
+      case "√":
+        // 使用适合开方的数（主要是完全平方数）
+        String numStr = getNumberForSqrt();
+        child = new Expression(numStr, parseNumber(numStr), null);
+
+        double sqrtValue = Math.sqrt(child.value);
+        if (child.mainOperator == null) {
+          return new Expression("√" + child.expression, sqrtValue, "√");
+        }
+        return new Expression("√(" + child.expression + ")", sqrtValue, "√");
+      default:
+        return child;
+    }
+  }
+
+  @Override
+  public String addParenthesesIfNeeded(Expression child, String parentOp, boolean isRightChild) {
+    if (child.mainOperator == null || child.mainOperator.equals("²") || child.mainOperator.equals("√")) {
+      return child.expression;
+    }
+
+    int parentPriority = getPriority(parentOp);
+    int childPriority = getPriority(child.mainOperator);
+
+    if (childPriority < parentPriority) {
+      return "(" + child.expression + ")";
+    }
+
+    if (isRightChild && (parentOp.equals("-") || parentOp.equals("/"))) {
+      if (parentPriority == childPriority) {
+        return "(" + child.expression + ")";
+      }
+    }
+
+    return child.expression;
+  }
+
+  @Override
+  public Expression setQuestion(int count) {
+    Expression result = firstSetQuestion(count);
+    // 确保初中题目包含平方或开方
+    while (!result.expression.contains("²") && !result.expression.contains("√")) {
+      result = firstSetQuestion(count);
+    }
+    return result;
+  }
+
+  public Expression firstSetQuestion(int count) {
+    if (count == 1) {
+      String numStr = getRandomNumber();
+      Expression expr = new Expression(numStr, parseNumber(numStr), null);
+      return probability(expr);
+    }
+    int leftCount = 1 + rand.nextInt(count - 1);
+    int rightCount = count - leftCount;
+    Expression left = firstSetQuestion(leftCount);
+    Expression right = firstSetQuestion(rightCount);
+    String op = getRandomOperator();
+    double value = 0;
+    switch (op) {
+      case "+":
+        value = left.value + right.value;
+        break;
+      case "-":
+        value = left.value - right.value;
+        if (value < 0) {
+          Expression temp = left;
+          left = right;
+          right = temp;
+          value = left.value - right.value;
+        }
+        break;
+      case "*":
+        value = left.value * right.value;
+        break;
+      case "/":
+        if (Math.abs(right.value) < 1e-10) {
+          right = firstSetQuestion(rightCount);
+        }
+        value = left.value / right.value;
+        break;
+    }
+    String leftExpr = addParenthesesIfNeeded(left, op, false);
+    String rightExpr = addParenthesesIfNeeded(right, op, true);
+    Expression result = new Expression(leftExpr + " " + op + " " + rightExpr, value, op);
+    result = probability(result);
+    return result;
+  }
+
+  public Expression probability(Expression result) {
+    if (rand.nextDouble() < 0.3) {
+      String[] unaryOps = {"²", "√"};
+      String unaryOp = unaryOps[rand.nextInt(unaryOps.length)];
+      result = applyUnary(result, unaryOp);
+      result.mainOperator = unaryOp;
+    }
+    return result;
+  }
+}

src/main/java/com/example/myapp/service/PrimaryQueSeting.java

@@ -0,0 +1,69 @@
+// PrimaryQueSeting.java
+package com.example.myapp.service;
+
+import com.example.myapp.model.Expression;
+
+public class PrimaryQueSeting extends AbstractQuestionSeting {
+
+  @Override
+  public Expression setQuestion(int count) {
+    if (count == 1) {
+      String expr = getRandomNumber();
+      return new Expression(expr, parseNumber(expr), null);
+    }
+
+    int leftCount = 1 + rand.nextInt(count - 1);
+    int rightCount = count - leftCount;
+    Expression left = setQuestion(leftCount);
+    Expression right = setQuestion(rightCount);
+
+    String op = getRandomOperator();
+
+    // 处理除数为0的情况
+    while (op.equals("/") && Math.abs(right.value) < 1e-10) {
+      right = setQuestion(rightCount);
+    }
+
+    // 确保减法结果不为负数
+    if (op.equals("-") && left.value < right.value) {
+      Expression temp = left;
+      left = right;
+      right = temp;
+    }
+
+    String leftExpr = addParenthesesIfNeeded(left, op, false);
+    String rightExpr = addParenthesesIfNeeded(right, op, true);
+
+    double value = switch (op) {
+      case "+" -> left.value + right.value;
+      case "-" -> left.value - right.value;
+      case "*" -> left.value * right.value;
+      case "/" -> left.value / right.value;
+      default -> 0;
+    };
+
+    return new Expression(leftExpr + " " + op + " " + rightExpr, value, op);
+  }
+
+  @Override
+  public String addParenthesesIfNeeded(Expression child, String parentOp, boolean isRightChild) {
+    if (child.mainOperator == null) {
+      return child.expression;
+    }
+
+    int parentPriority = getPriority(parentOp);
+    int childPriority = getPriority(child.mainOperator);
+
+    if (childPriority < parentPriority) {
+      return "(" + child.expression + ")";
+    }
+
+    if (isRightChild && (parentOp.equals("-") || parentOp.equals("/"))) {
+      if (parentPriority == childPriority) {
+        return "(" + child.expression + ")";
+      }
+    }
+
+    return child.expression;
+  }
+}

src/main/java/com/example/myapp/service/QueSetingFactory.java

@@ -0,0 +1,18 @@
+// QueSetingFactory.java
+package com.example.myapp.service;
+
+public class QueSetingFactory {
+  public QuestionSeting getQueSeting(String type) {
+    switch (type) {
+      case "小学":
+        return new PrimaryQueSeting();
+      case "初中":
+        return new MiddleQueSeting();
+      case "高中":
+        return new HighQueSeting();
+      default:
+        System.out.println("类型错误");
+        return null;
+    }
+  }
+}

src/main/java/com/example/myapp/service/QuestionSeting.java

@@ -0,0 +1,8 @@
+// QuestionSeting.java
+package com.example.myapp.service;
+
+import com.example.myapp.model.Expression;
+
+public interface QuestionSeting {
+  Expression setQuestion(int count);
+}

src/main/java/com/example/myapp/service/UserService.java

@@ -0,0 +1,181 @@
+package com.example.myapp.service;
+
+import com.example.myapp.model.User;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class UserService {
+  private Map<String, User> users;
+  private Map<String, String> usernameToEmail;
+  private Map<String, String> registrationCodes;
+  private Map<String, String> resetPasswordCodes;
+
+  private final FileStorageService fileStorageService;
+  private static final UserService instance = new UserService();
+
+  public static UserService getInstance() {
+    return instance;
+  }
+
+  private UserService() {
+    this.fileStorageService = new FileStorageService();
+    loadData();
+  }
+
+  private void loadData() {
+    users = fileStorageService.readUsersData();
+    registrationCodes = fileStorageService.readRegistrationCodesData();
+    resetPasswordCodes = fileStorageService.readResetPasswordCodesData();
+
+    usernameToEmail = new ConcurrentHashMap<>();
+    if (users != null) {
+      for (User user : users.values()) {
+        if (user.getUsername() != null && !user.getUsername().trim().isEmpty()) {
+          usernameToEmail.put(user.getUsername().toLowerCase(), user.getEmail());
+        }
+      }
+    }
+
+    if (users == null) users = new ConcurrentHashMap<>();
+    if (registrationCodes == null) registrationCodes = new ConcurrentHashMap<>();
+    if (resetPasswordCodes == null) resetPasswordCodes = new ConcurrentHashMap<>();
+    if (usernameToEmail == null) usernameToEmail = new ConcurrentHashMap<>();
+  }
+
+  private void saveUsers() {
+    fileStorageService.writeUsersData(users);
+  }
+
+  private void saveRegistrationCodes() {
+    fileStorageService.writeRegistrationCodesData(registrationCodes);
+  }
+
+  private void saveResetPasswordCodes() {
+    fileStorageService.writeResetPasswordCodesData(resetPasswordCodes);
+  }
+
+  public boolean emailExists(String email) {
+    return users.containsKey(email);
+  }
+
+  public boolean usernameExists(String username) {
+    return usernameToEmail.containsKey(username.toLowerCase());
+  }
+
+  public User getUserByIdentifier(String identifier) {
+    if (identifier.contains("@")) {
+      return users.get(identifier);
+    } else {
+      String email = usernameToEmail.get(identifier.toLowerCase());
+      return email != null ? users.get(email) : null;
+    }
+  }
+
+  public boolean userExists(String identifier) {
+    if (identifier.contains("@")) {
+      return emailExists(identifier);
+    } else {
+      return usernameExists(identifier);
+    }
+  }
+
+  public boolean isUserRegistered(String email) {
+    User user = users.get(email);
+    return user != null && user.getPasswordHash() != null && !user.getPasswordHash().isEmpty();
+  }
+
+  public void createPendingUser(String email, String code) {
+    if (users.containsKey(email)) {
+      User existingUser = users.get(email);
+      if (existingUser.getPasswordHash() == null || existingUser.getPasswordHash().isEmpty()) {
+        registrationCodes.put(email, code);
+        saveRegistrationCodes();
+        return;
+      }
+    }
+
+    users.putIfAbsent(email, new User(email, null));
+    registrationCodes.put(email, code);
+    saveUsers();
+    saveRegistrationCodes();
+  }
+
+  public boolean setUsername(String email, String username) {
+    if (username == null || username.trim().isEmpty()) {
+      return false;
+    }
+
+    String usernameLower = username.toLowerCase();
+    if (usernameToEmail.containsKey(usernameLower)) {
+      return false;
+    }
+
+    User user = users.get(email);
+    if (user != null) {
+      if (user.getUsername() != null) {
+        usernameToEmail.remove(user.getUsername().toLowerCase());
+      }
+
+      user.setUsername(username);
+      usernameToEmail.put(usernameLower, email);
+      saveUsers();
+      return true;
+    }
+    return false;
+  }
+
+  public boolean verifyCode(String email, String code) {
+    String storedCode = registrationCodes.get(email);
+    if (storedCode != null && storedCode.equals(code)) {
+      User u = users.get(email);
+      if (u != null) {
+        u.setVerified(true);
+        registrationCodes.remove(email);
+        saveUsers();
+        saveRegistrationCodes();
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // 忘记密码相关方法
+  public void createResetPasswordCode(String email, String code) {
+    resetPasswordCodes.put(email, code);
+    saveResetPasswordCodes();
+  }
+
+  public boolean verifyResetPasswordCode(String email, String code) {
+    String storedCode = resetPasswordCodes.get(email);
+    if (storedCode != null && storedCode.equals(code)) {
+      resetPasswordCodes.remove(email);
+      saveResetPasswordCodes();
+      return true;
+    }
+    return false;
+  }
+
+  public void setPassword(String email, String passwordHash) {
+    User u = users.get(email);
+    if (u != null) {
+      u.setPasswordHash(passwordHash);
+      u.setVerified(true);
+      saveUsers();
+    }
+  }
+
+  public boolean checkPassword(String identifier, String plain) {
+    User user = getUserByIdentifier(identifier);
+    if (user == null || user.getPasswordHash() == null) {
+      return false;
+    }
+
+    return com.example.myapp.util.PasswordUtil.check(plain, user.getPasswordHash());
+  }
+
+  public String getDisplayName(String identifier) {
+    User user = getUserByIdentifier(identifier);
+    if (user == null) return identifier;
+    return user.getUsername() != null ? user.getUsername() : user.getEmail();
+  }
+}

src/main/java/com/example/myapp/util/PasswordUtil.java

@@ -0,0 +1,21 @@
+package com.example.myapp.util;
+
+import org.mindrot.jbcrypt.BCrypt;
+import java.util.regex.Pattern;
+
+public class PasswordUtil {
+  private static final Pattern validPattern = Pattern.compile("^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d).{6,10}$");
+
+  public static boolean validatePasswordRules(String pwd){
+    if(pwd==null) return false;
+    return validPattern.matcher(pwd).matches();
+  }
+
+  public static String hash(String plain){
+    return BCrypt.hashpw(plain, BCrypt.gensalt(12));
+  }
+
+  public static boolean check(String plain, String hash){
+    return BCrypt.checkpw(plain, hash);
+  }
+}