src/model/Login.java

@@ -64,6 +64,19 @@ public class Login {
     return null;
   }
 
+  public static boolean isEmailExists(String email){
+    if(email == null || email.trim().isEmpty()){
+      return false;
+    }
+    for(Account acc:accounts.values()){
+      if(acc.email != null && acc.email.equalsIgnoreCase(email.trim())){
+        return true;
+      }
+    }
+    return false;
+  }
+
+
   // 注册（GUI 调用），若用户名已存在返回 false
   // 注册（GUI 调用），若用户名或邮箱已存在返回 false
   public static synchronized boolean register(String username, String password, Level level,
@@ -73,6 +86,10 @@ public class Login {
       return false;
     }
 
+    if(isEmailExists(email)){
+      return false;
+    }
+
     // 检查邮箱是否重复
     for (Account existing : accounts.values()) {
       if (existing.email != null && existing.email.equalsIgnoreCase(email)) {

src/view/RegisterFrame.java

@@ -1,6 +1,6 @@
 package view;
 
-import java.awt.GridLayout;
+import java.awt.*;
 import java.util.Properties;
 import java.util.Random;
 
@@ -25,7 +25,6 @@ import jakarta.mail.internet.MimeMessage;
 
 import model.Login;
 import model.LanguageSwitch;
-
 /**
  * 注册界面（使用 QQ 邮箱发送验证码）
  */
@@ -33,19 +32,21 @@ public class RegisterFrame extends JDialog {
 
   private JTextField usernameField;
   private JTextField emailField;
-  private JComboBox<String> levelBox;
   private JPasswordField pwdField;
   private JPasswordField pwdField2;
   private JTextField codeField;
   private String lastCode;
 
+  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);
+  }
   // QQ 邮箱配置
   private static final String FROM_EMAIL = "songqifeng.sqf@qq.com";
   private static final String AUTH_CODE = "gcyschltjgxedgjd"; // ⚠️ 在 QQ 邮箱里申请的授权码
-
   public RegisterFrame(JFrame owner) {
     super(owner, "注册新用户", true);
-    setSize(420, 320);
+    setSize(420, 300);
     setLocationRelativeTo(owner);
 
     JPanel p = new JPanel(new GridLayout(7, 2, 6, 6));
@@ -58,11 +59,7 @@ public class RegisterFrame extends JDialog {
     emailField = new JTextField();
     p.add(emailField);
 
-    p.add(new JLabel("年级:"));
-    levelBox = new JComboBox<>(new String[]{"小学", "初中", "高中"});
-    p.add(levelBox);
-
-    p.add(new JLabel("密码 (6-10位，含大小写与数字):"));
+    p.add(new JLabel("密码 (6-10位，需含大小写与数字):"));
     pwdField = new JPasswordField();
     p.add(pwdField);
 
@@ -70,11 +67,15 @@ public class RegisterFrame extends JDialog {
     pwdField2 = new JPasswordField();
     p.add(pwdField2);
 
-    JButton sendCodeBtn = new JButton("发送注册码");
-    p.add(sendCodeBtn);
+    p.add(new JLabel("请输入注册码:"));
     codeField = new JTextField();
     p.add(codeField);
 
+    JButton sendCodeBtn = new JButton("发送注册码");
+    p.add(sendCodeBtn);
+
+    p.add(new JLabel());
+
     JButton regBtn = new JButton("注册");
     p.add(regBtn);
     JButton cancelBtn = new JButton("取消");
@@ -84,10 +85,16 @@ public class RegisterFrame extends JDialog {
 
     sendCodeBtn.addActionListener(e -> {
       String email = emailField.getText().trim();
-      if (email.isEmpty() || !email.contains("@")) {
+      if (email.isEmpty() || !isValidEmail(email)) {
         JOptionPane.showMessageDialog(this, "请输入有效邮箱");
         return;
       }
+
+      if(Login.isEmailExists(email)){
+        JOptionPane.showMessageDialog(this,"该邮箱已经被注册，请使用其他邮箱");
+        return;
+      }
+
       lastCode = String.format("%04d", new Random().nextInt(10000));
       boolean sent = sendEmail(email, lastCode);
       if (sent) {
@@ -108,6 +115,10 @@ public class RegisterFrame extends JDialog {
         JOptionPane.showMessageDialog(this, "请填写完整信息并输入注册码");
         return;
       }
+      if(Login.isEmailExists(email)){
+        JOptionPane.showMessageDialog(this,"该邮箱已被注册，请使用其他邮箱");
+        return;
+      }
       if (!code.equals(lastCode)) {
         JOptionPane.showMessageDialog(this, "注册码错误，请重新输入");
         return;
@@ -120,8 +131,9 @@ public class RegisterFrame extends JDialog {
         JOptionPane.showMessageDialog(this, "密码不满足要求：6-10位且包含大写、小写和数字");
         return;
       }
-      String levelStr = (String) levelBox.getSelectedItem();
-      Login.Level lv = LanguageSwitch.chineseToLevel(levelStr);
+
+      Login.Level lv = Login.Level.PRIMARY;
+
       boolean ok = Login.register(u, pwd, lv, email);
       if (!ok) {
         JOptionPane.showMessageDialog(this, "用户名或邮箱已存在，请换一个用户名");