src/main/java/com/mathgenerator/controller/ChangePasswordController.java

@@ -0,0 +1,90 @@
+package com.mathgenerator.controller;
+
+import com.mathgenerator.model.User;
+import com.mathgenerator.service.UserService;
+import javafx.event.ActionEvent;
+import javafx.fxml.FXML;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Parent;
+import javafx.scene.Scene;
+import javafx.scene.control.Button;
+import javafx.scene.control.Label;
+import javafx.scene.control.PasswordField;
+import javafx.stage.Stage;
+import java.io.IOException;
+
+public class ChangePasswordController {
+
+    private final UserService userService = new UserService();
+    private User currentUser;
+
+    @FXML private PasswordField oldPasswordField;
+    @FXML private PasswordField newPasswordField;
+    @FXML private PasswordField confirmNewPasswordField;
+    @FXML private Button confirmButton;
+    @FXML private Button backButton;
+    @FXML private Label statusLabel;
+
+    /**
+     * 初始化控制器，接收当前用户信息
+     */
+    public void initData(User user) {
+        this.currentUser = user;
+    }
+
+    @FXML
+    private void handleConfirmAction(ActionEvent event) {
+        // 1. 获取输入
+        String oldPassword = oldPasswordField.getText();
+        String newPassword = newPasswordField.getText();
+        String confirmNewPassword = confirmNewPasswordField.getText();
+
+        // 2. 输入校验
+        if (oldPassword.isEmpty() || newPassword.isEmpty() || confirmNewPassword.isEmpty()) {
+            statusLabel.setText("所有密码字段都不能为空！");
+            return;
+        }
+        if (!newPassword.equals(confirmNewPassword)) {
+            statusLabel.setText("两次输入的新密码不匹配！");
+            return;
+        }
+        if (!UserService.isPasswordValid(newPassword)) {
+            statusLabel.setText("新密码格式错误！必须为6-10位，且包含大小写字母和数字。");
+            return;
+        }
+
+        // 3. 调用后端服务修改密码
+        boolean success = userService.changePassword(
+                currentUser.username(),
+                oldPassword,
+                newPassword
+        );
+
+        // 4. 更新UI反馈
+        if (success) {
+            statusLabel.setText("密码修改成功！请返回主菜单。");
+            confirmButton.setDisable(true); // 防止重复点击
+        } else {
+            statusLabel.setText("修改失败：当前密码错误。");
+        }
+    }
+
+    /**
+     * 处理返回按钮事件，返回主菜单
+     */
+    @FXML
+    private void handleBackAction(ActionEvent event) {
+        try {
+            FXMLLoader loader = new FXMLLoader(getClass().getResource("/com/mathgenerator/view/MainMenuView.fxml"));
+            Parent root = loader.load();
+            MainMenuController controller = loader.getController();
+            controller.initData(currentUser); // 将用户信息传回主菜单
+
+            Stage stage = (Stage) backButton.getScene().getWindow();
+            stage.setScene(new Scene(root));
+            stage.setTitle("主菜单");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}

src/main/java/com/mathgenerator/controller/LoginController.java

@@ -15,7 +15,7 @@ import javafx.stage.Stage;
 
 import java.io.IOException;
 import java.util.Optional;
-
+import com.mathgenerator.util.ValidationUtils;
 public class LoginController {
 
     // 依赖注入后端服务
@@ -46,7 +46,13 @@ public class LoginController {
         String username = usernameField.getText();
         String password = passwordField.getText();
 
-        if (username.isEmpty() || password.isEmpty()) {
+        // --- 2. 使用工具类进行校验 ---
+        if (!ValidationUtils.isUsernameValid(username)) {
+            statusLabel.setText("登录失败：用户名不能为空且不能包含空格。");
+            return;
+        }
+
+        if (password.isEmpty()) {
             statusLabel.setText("用户名和密码不能为空！");
             return;
         }

src/main/java/com/mathgenerator/controller/MainMenuController.java

@@ -48,11 +48,26 @@ public class MainMenuController {
 
     @FXML
     private void handleChangePasswordAction(ActionEvent event) {
-        // TODO: 跳转到修改密码界面
-        statusLabel.setText("修改密码功能待实现。");
-    }
+        try {
+            // 1\. 加载 FXML 文件
+            FXMLLoader loader = new FXMLLoader(getClass().getResource("/com/mathgenerator/view/ChangePasswordView.fxml"));
+            Parent root = loader.load();
+            // 2\. 获取新界面的控制器
+            ChangePasswordController controller = loader.getController();
 
-    @FXML
+            // 3\. 调用控制器的方法，传递当前用户信息
+            controller.initData(currentUser);
+
+            // 4\. 显示新场景
+            Stage stage = (Stage) logoutButton.getScene().getWindow();
+            stage.setScene(new Scene(root));
+            stage.setTitle("修改密码");
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+        @FXML
     private void handleLogoutAction(ActionEvent event) {
         // 跳转回登录界面
         loadScene("/com/mathgenerator/view/LoginView.fxml");

src/main/java/com/mathgenerator/controller/QuizController.java

@@ -62,7 +62,7 @@ public class QuizController {
     }
 
     /**
-     * 显示当前的题目和选项
+     * 显示当前的题目和选项 (已更新，增加ABCD前缀)
      */
     private void displayCurrentQuestion() {
         ChoiceQuestion currentQuestion = questions.get(currentQuestionIndex);
@@ -72,8 +72,10 @@ public class QuizController {
         questionTextLabel.setText(currentQuestion.questionText());
 
         List<RadioButton> radioButtons = List.of(option1, option2, option3, option4);
+        String[] prefixes = {"A. ", "B. ", "C. ", "D. "}; // 定义选项前缀
         for (int i = 0; i < radioButtons.size(); i++) {
-            radioButtons.get(i).setText(currentQuestion.options().get(i));
+            // 将前缀和选项文本结合起来
+            radioButtons.get(i).setText(prefixes[i] + currentQuestion.options().get(i));
         }
 
         optionsGroup.selectToggle(null); // 清除上一次的选择

src/main/java/com/mathgenerator/controller/RegisterController.java

@@ -12,7 +12,7 @@ import javafx.scene.control.PasswordField;
 import javafx.scene.control.TextField;
 import javafx.stage.Stage;
 import java.io.IOException;
-
+import com.mathgenerator.util.ValidationUtils;
 public class RegisterController {
 
     private final UserService userService = new UserService();
@@ -50,41 +50,52 @@ public class RegisterController {
 
     @FXML
     private void handleRegisterAction(ActionEvent event) {
-        // 1. 字段校验
-        if (usernameField.getText().isEmpty() || emailField.getText().isEmpty() ||
-                verificationCodeField.getText().isEmpty() || passwordField.getText().isEmpty()) {
-            statusLabel.setText("所有字段都不能为空！");
-            return;
-        }
-        if (!passwordField.getText().equals(confirmPasswordField.getText())) {
-            statusLabel.setText("两次输入的密码不匹配！");
+        // 1. 字段校验 (已简化，不再校验密码)
+        String username = usernameField.getText();
+        String email = emailField.getText();
+
+        if (!ValidationUtils.isUsernameValid(username) || !ValidationUtils.isEmailValid(email) ||
+                verificationCodeField.getText().isEmpty()) {
+            statusLabel.setText("所有字段都不能为空且格式正确！");
             return;
         }
         if (this.sentCode == null || !this.sentCode.equals(verificationCodeField.getText())) {
             statusLabel.setText("验证码错误！");
             return;
         }
-        if (!UserService.isPasswordValid(passwordField.getText())) {
-            statusLabel.setText("密码格式错误！必须为6-10位，且包含大小写字母和数字。");
-            return;
-        }
 
-        // 2. 调用后端服务进行注册
-        boolean success = userService.register(
-                usernameField.getText(),
-                emailField.getText(),
-                passwordField.getText()
-        );
+        // 2. 调用后端服务进行无密码注册
+        boolean success = userService.register(username, email);
 
-        // 3. 根据结果更新UI
+        // 3. 根据结果更新UI或跳转
         if (success) {
-            statusLabel.setText("注册成功！请返回登录。");
-            registerButton.setDisable(true);
+            statusLabel.setText("注册成功！请设置您的密码。");
+            // 成功后，加载设置密码界面，并传递用户名
+            loadSetPasswordScene(username);
         } else {
             statusLabel.setText("注册失败：用户名或邮箱已被占用。");
         }
     }
 
+    /**
+     * (新增) 加载设置密码界面，并传递用户名。
+     */
+    private void loadSetPasswordScene(String username) {
+        try {
+            FXMLLoader loader = new FXMLLoader(getClass().getResource("/com/mathgenerator/view/SetPasswordView.fxml"));
+            Parent root = loader.load();
+
+            SetPasswordController controller = loader.getController();
+            controller.initData(username); // 将用户名传递给新界面的控制器
+
+            Stage stage = (Stage) registerButton.getScene().getWindow();
+            stage.setScene(new Scene(root));
+            stage.setTitle("设置密码");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
     @FXML
     private void handleBackToLoginAction(ActionEvent event) {
         loadScene("/com/mathgenerator/view/LoginView.fxml");

src/main/java/com/mathgenerator/controller/SetPasswordController.java

@@ -0,0 +1,80 @@
+package com.mathgenerator.controller;
+
+import com.mathgenerator.model.User;
+import com.mathgenerator.service.UserService;
+import com.mathgenerator.util.ValidationUtils;
+import javafx.event.ActionEvent;
+import javafx.fxml.FXML;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Parent;
+import javafx.scene.Scene;
+import javafx.scene.control.Button;
+import javafx.scene.control.Label;
+import javafx.scene.control.PasswordField;
+import javafx.stage.Stage;
+
+import java.io.IOException;
+
+public class SetPasswordController {
+
+    private final UserService userService = new UserService();
+    private String username;
+
+    @FXML private Label promptLabel;
+    @FXML private PasswordField newPasswordField;
+    @FXML private PasswordField confirmPasswordField;
+    @FXML private Button confirmButton;
+    @FXML private Label statusLabel;
+
+    /**
+     * 接收从注册界面传递过来的用户名
+     */
+    public void initData(String username) {
+        this.username = username;
+        promptLabel.setText("为您的账户 " + username + " 设置密码");
+    }
+
+    @FXML
+    private void handleConfirmAction(ActionEvent event) {
+        String newPassword = newPasswordField.getText();
+        String confirmPassword = confirmPasswordField.getText();
+
+        if (!newPassword.equals(confirmPassword)) {
+            statusLabel.setText("两次输入的密码不匹配！");
+            return;
+        }
+        if (!ValidationUtils.isPasswordValid(newPassword)) {
+            statusLabel.setText("新密码格式错误！必须为6-10位，且包含大小写字母和数字。");
+            return;
+        }
+
+        // 调用后端服务设置密码
+        boolean success = userService.setPassword(this.username, newPassword);
+
+        if (success) {
+            statusLabel.setText("密码设置成功！正在进入主菜单...");
+            // 密码设置成功后，获取完整的用户信息并直接跳转到主菜单
+            userService.findUserByUsername(this.username).ifPresent(this::loadMainMenu);
+        } else {
+            statusLabel.setText("密码设置失败，请稍后重试或重新注册。");
+        }
+    }
+
+    /**
+     * 加载主菜单界面，并传递用户信息 (实现自动登录)
+     */
+    private void loadMainMenu(User user) {
+        try {
+            FXMLLoader loader = new FXMLLoader(getClass().getResource("/com/mathgenerator/view/MainMenuView.fxml"));
+            Parent root = loader.load();
+            MainMenuController controller = loader.getController();
+            controller.initData(user); // 将完整的User对象传递给主菜单
+
+            Stage stage = (Stage) confirmButton.getScene().getWindow();
+            stage.setScene(new Scene(root));
+            stage.setTitle("主菜单");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}

src/main/java/com/mathgenerator/generator/PrimarySchoolGenerator.java

@@ -172,25 +172,6 @@ public class PrimarySchoolGenerator implements QuestionGenerator {
         parts.add(startIndex, "(");
     }
 
-    // 在 PrimarySchoolGenerator.java 中添加这个方法
-    /**
-     * 仅生成题目字符串，不包含答案和选项。
-     * 这是为了方便子类（初中、高中）继承和修改题干。
-     * @return 题目文本字符串
-     */
-    public String generateBasicQuestionText() {
-        ThreadLocalRandom random = ThreadLocalRandom.current();
-        int operandCount = random.nextInt(2, 5);
-        List<String> parts = new ArrayList<>();
-        parts.add(String.valueOf(getOperand()));
-        for (int i = 1; i < operandCount; i++) {
-            parts.add(getRandomOperator());
-            parts.add(String.valueOf(getOperand()));
-        }
-        if (operandCount > 2 && random.nextBoolean()) {
-            addParentheses(parts);
-        }
-        return String.join(" ", parts);
-    }
+
 
 }

src/main/java/com/mathgenerator/service/UserService.java

@@ -35,18 +35,20 @@ public class UserService {
     }
 
     private Map<String, User> loadUsersFromFile() {
-        try {
-            if (Files.exists(USER_FILE_PATH) && Files.size(USER_FILE_PATH) > 0) {
-                try (FileReader reader = new FileReader(USER_FILE_PATH.toFile())) {
-                    Type type = new TypeToken<Map<String, User>>() {}.getType();
-                    Map<String, User> loadedUsers = gson.fromJson(reader, type);
-                    return loadedUsers != null ? new ConcurrentHashMap<>(loadedUsers) : new ConcurrentHashMap<>();
-                }
-            }
+        // 如果文件不存在，直接返回一个空的Map，不再创建默认用户
+        if (!Files.exists(USER_FILE_PATH)) {
+            return new ConcurrentHashMap<>();
+        }
+
+        try (FileReader reader = new FileReader(USER_FILE_PATH.toFile())) {
+            Type type = new TypeToken<Map<String, User>>() {}.getType();
+            Map<String, User> loadedUsers = gson.fromJson(reader, type);
+            // 如果文件为空或格式错误，也返回一个空的Map
+            return loadedUsers != null ? new ConcurrentHashMap<>(loadedUsers) : new ConcurrentHashMap<>();
         } catch (IOException e) {
             System.err.println("错误：加载用户文件失败 - " + e.getMessage());
+            return new ConcurrentHashMap<>();
         }
-        return new ConcurrentHashMap<>();
     }
 
     private void saveUsers() {
@@ -103,32 +105,49 @@ public class UserService {
     }
 
     /**
-     * 注册新用户。
-     * @return 成功返回true, 否则返回false
+     * (已修正) 注册一个没有初始密码的新用户。
+     * @param username 新用户的用户名
+     * @param email 新用户的邮箱
+     * @return 注册成功返回true, 如果用户名或邮箱已存在则返回false。
      */
-    public boolean register(String username, String email, String password) {
-        // 1. 基础校验：防止 null 或空白输入
-        if (username == null || email == null || password == null ||
-                username.trim().isEmpty() || email.trim().isEmpty() || password.trim().isEmpty()) {
-            return false;
+    public boolean register(String username, String email) {
+        if (userDatabase.containsKey(username)) {
+            return false; // 用户名已存在
         }
-
-        // 2. 检查用户名或邮箱是否已存在（使用 Objects.equals 安全比较）
-        boolean usernameExists = userDatabase.containsKey(username);
-        boolean emailExists = userDatabase.values().stream()
-                .anyMatch(u -> Objects.equals(u.email(), email));
-
-        if (usernameExists || emailExists) {
-            return false; // 用户名或邮箱已存在
+        // 检查数据库中已存在的用户的email是否与新email相同
+        // 使用 email.equals(u.email()) 可以安全地处理 u.email() 为 null 的情况
+        if (userDatabase.values().stream()
+                .anyMatch(u -> email.equals(u.email()))) {
+            return false; // 邮箱已存在
         }
 
-        // 3. 创建新用户并保存
-        User newUser = new User(username, email, password);
+        // --- 核心修正在这里 ---
+        // 创建用户时，密码字段设为 null，表示该用户处于“待设置密码”状态
+        User newUser = new User(username, email, null);
         userDatabase.put(username, newUser);
         saveUsers();
         return true;
     }
 
+    /**
+     * (新增) 为指定用户设置初始密码。
+     * @param username 要设置密码的用户名
+     * @param password 要设置的新密码
+     * @return 成功设置返回 true, 如果用户不存在则返回 false
+     */
+    public boolean setPassword(String username, String password) {
+        return findUserByUsername(username)
+                .map(user -> {
+                    // 只有当用户当前密码为 null 时才允许设置
+                    if (user.password() == null) {
+                        User updatedUser = new User(user.username(), user.email(), password);
+                        userDatabase.put(username, updatedUser);
+                        saveUsers();
+                        return true;
+                    }
+                    return false; // 用户已经有密码，不能通过此方法设置
+                }).orElse(false);
+    }
     /**
      * 验证密码是否符合复杂度要求。
      * @param password 待验证的密码

src/main/java/com/mathgenerator/util/ValidationUtils.java

@@ -0,0 +1,52 @@
+package com.mathgenerator.util;
+
+import java.util.regex.Pattern;
+
+/**
+ * 一个包含静态校验方法的工具类。
+ * 用于集中管理项目中所有的数据格式验证逻辑。
+ */
+public final class ValidationUtils {
+
+    // 密码策略: 6-10位, 必须包含大小写字母和数字
+    private static final Pattern PASSWORD_PATTERN =
+            Pattern.compile("^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d).{6,10}$");
+
+    // 用户名策略: 不包含任何空白字符
+    private static final Pattern USERNAME_NO_WHITESPACE_PATTERN =
+            Pattern.compile("^\\S+$");
+
+    // 私有构造函数，防止这个工具类被实例化
+    private ValidationUtils() {}
+
+    /**
+     * 验证用户名格式是否有效。
+     * 当前规则：不允许包含任何空格或空白字符。
+     * @param username 待验证的用户名
+     * @return 如果有效返回true, 否则返回false
+     */
+    public static boolean isUsernameValid(String username) {
+        if (username == null || username.isEmpty()) {
+            return false;
+        }
+        return USERNAME_NO_WHITESPACE_PATTERN.matcher(username).matches();
+    }
+
+    /**
+     * 验证密码是否符合复杂度要求。
+     * @param password 待验证的密码
+     * @return 如果符合要求返回true
+     */
+    public static boolean isPasswordValid(String password) {
+        return password != null && PASSWORD_PATTERN.matcher(password).matches();
+    }
+
+    /**
+     * 验证邮箱格式是否有效 (简单校验)。
+     * @param email 待验证的邮箱
+     * @return 如果格式基本正确返回true
+     */
+    public static boolean isEmailValid(String email) {
+        return email != null && !email.isEmpty() && email.contains("@");
+    }
+}

src/main/resources/com/mathgenerator/view/ChangePasswordView.fxml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.control.Button?>
+<?import javafx.scene.control.Label?>
+<?import javafx.scene.control.PasswordField?>
+<?import javafx.scene.layout.VBox?>
+<?import javafx.scene.text.Font?>
+
+<VBox alignment="CENTER" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="450.0" spacing="15.0" style="-fx-background-color: #f4f4f4;" xmlns="http://javafx.com/javafx/17" xmlns:fx="http://javafx.com/fxml/1" fx:controller="com.mathgenerator.controller.ChangePasswordController">
+    <children>
+        <Label text="修改密码">
+            <font>
+                <Font name="System Bold" size="24.0" />
+            </font>
+        </Label>
+        <PasswordField fx:id="oldPasswordField" maxWidth="300.0" promptText="当前密码" />
+        <PasswordField fx:id="newPasswordField" maxWidth="300.0" promptText="新密码 (6-10位, 含大小写字母和数字)" />
+        <PasswordField fx:id="confirmNewPasswordField" maxWidth="300.0" promptText="确认新密码" />
+        <Button fx:id="confirmButton" mnemonicParsing="false" onAction="#handleConfirmAction" prefWidth="120.0" text="确认修改" />
+        <Button fx:id="backButton" mnemonicParsing="false" onAction="#handleBackAction" style="-fx-background-color: #6c757d;" text="返回主菜单" textFill="WHITE" />
+        <Label fx:id="statusLabel" textFill="RED" wrapText="true">
+            <VBox.margin>
+                <Insets top="10.0" />
+            </VBox.margin>
+        </Label>
+    </children>
+    <padding>
+        <Insets bottom="20.0" left="20.0" right="20.0" top="20.0" />
+    </padding>
+</VBox>

src/main/resources/com/mathgenerator/view/RegisterView.fxml

@@ -24,8 +24,6 @@
                 <Button fx:id="sendCodeButton" mnemonicParsing="false" onAction="#handleSendCodeAction" text="发送验证码" />
             </children>
         </HBox>
-        <PasswordField fx:id="passwordField" maxWidth="300.0" promptText="设置密码 (6-10位, 含大小写字母和数字)" />
-        <PasswordField fx:id="confirmPasswordField" maxWidth="300.0" promptText="确认密码" />
         <Button fx:id="registerButton" mnemonicParsing="false" onAction="#handleRegisterAction" prefWidth="120.0" text="确认注册" />
         <Button fx:id="backToLoginButton" mnemonicParsing="false" onAction="#handleBackToLoginAction" style="-fx-background-color: #6c757d;" text="返回登录" textFill="WHITE" />
         <Label fx:id="statusLabel" textFill="RED" wrapText="true">

src/main/resources/com/mathgenerator/view/SetPasswordView.fxml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.control.Button?>
+<?import javafx.scene.control.Label?>
+<?import javafx.scene.control.PasswordField?>
+<?import javafx.scene.layout.VBox?>
+<?import javafx.scene.text.Font?>
+
+<VBox alignment="CENTER" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="350.0" prefWidth="450.0" spacing="15.0" style="-fx-background-color: #f4f4f4;" xmlns="http://javafx.com/javafx/17" xmlns:fx="http://javafx.com/fxml/1" fx:controller="com.mathgenerator.controller.SetPasswordController">
+    <children>
+        <Label text="设置您的初始密码">
+            <font>
+                <Font name="System Bold" size="24.0" />
+            </font>
+        </Label>
+        <Label fx:id="promptLabel" text="为您的账户 [用户名] 设置密码" />
+        <PasswordField fx:id="newPasswordField" maxWidth="300.0" promptText="新密码 (6-10位, 含大小写字母和数字)" />
+        <PasswordField fx:id="confirmPasswordField" maxWidth="300.0" promptText="确认新密码" />
+        <Button fx:id="confirmButton" mnemonicParsing="false" onAction="#handleConfirmAction" prefWidth="120.0" text="确认并进入" />
+        <Label fx:id="statusLabel" textFill="RED" wrapText="true">
+            <VBox.margin>
+                <Insets top="10.0" />
+            </VBox.margin>
+        </Label>
+    </children>
+    <padding>
+        <Insets bottom="20.0" left="20.0" right="20.0" top="20.0" />
+    </padding>
+</VBox>