Java-学生管理系统

• 登录部分

public class LoginFrame extends JFrame {
   
    private String username;
    private String password;

    private JLabel lblUsername;
    private JLabel lblPassword;
    private JTextField txtUsername;
    private JPasswordField txtPassword;

    private JButton btnOK;
    private JButton btnCancel;
    private JButton btnSign;

    private JPanel panel, panel1, panel2, panel3, panel4;

    /**
     * 有参构造方法
     *
     * @param title
     */
    public LoginFrame(String title) {
   
        super(title);
        initGUI(); // 调用初始化图形用户界面方法
        eventsHandling(); // 调用事件处理方法
    }

    /**
     * 事件处理
     */
    private void eventsHandling() {
   
        // 给【确定】按钮注册监听器
        btnOK.addActionListener(new ActionListener() {
   
            @Override
            public void actionPerformed(ActionEvent e) {
   
                // 获取用户输入的用户名和密码
                username = txtUsername.getText().trim();
                password = new String(txtPassword.getPassword());
                // 创建用户服务对象
                UserService userService = new UserService();
                // 调用服务对象的登录方法
                User user = userService.login(username, password);
                // 判断用户登录是否成功
                if (user != null) {
   
                    // 弹出消息提示窗口
                    try {
   
                        new Main();
                        JOptionPane.showMessageDialog(null, "恭喜【"+ username + "】登录成功~");
                    } catch (IOException ioException) {
   
                        System.err.println("失败~");
                    }
                    dispose();
                } else {
   
                    // 弹出消息提示窗口
                    JOptionPane.showMessageDialog(null, "【"+ username + "】登录失败~\n用户名或密码错误~");
                    // 情况两个文本框
                    txtUsername.setText("");
                    txtPassword.setText("");
                    // 让姓名文本框获取焦点
                    txtUsername.requestFocus();
                }
            }
        });

        //给取消按钮注册监听器
        btnCancel.addActionListener(new ActionListener() {
   
            @Override
            public void actionPerformed(ActionEvent e)