如何使用 Java Swing 在按钮操作侦听器上正确设置 session

Question

Today I am practicing new tech skills which is java swing with mysql for the database. My task today is to create a login form and when the user click the sign in button, user will go to the next form together with the details of users.

Goal: How to get the users details to the second form?

1. Is java swing have a session like what programming language have?
2. If yes, what term name use session on java swing programming?

Login Form:

Sign In Function:

JButton btnNewButton = new JButton("Sign In");
    btnNewButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            String email = EmailTxtInput.getText();
            String password = PassTxtInput.getText();
            
            if(email.length() == 0) {
                JOptionPane.showMessageDialog(null,"Invalid Email");
            }
            else if(password.length() == 0) {
                JOptionPane.showMessageDialog(null,"Invalid Password");
            }else {
                
                try {
                    Class.forName("com.mysql.cj.jdbc.Driver");
                    Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/health_check?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC","root","");
                    String query = "SELECT COUNT(*) as checking_if_exist, role, first_name, users_id FROM users WHERE email = '"+email+"' AND password = '" +password +"' ";
                    
                    Statement sta = con.createStatement();
                    ResultSet rs = sta.executeQuery(query);
                    rs.next();
                    
                    
                    if(rs.getInt(1) == 1) {
                        
                        JOptionPane.showMessageDialog(null,"Successfully Login");
                        
                        if(rs.getInt(2) == 1) {
                            
                            AdminDashboardScreen admindashboardscreen = new AdminDashboardScreen();
                            
                            admindashboardscreen.setUndecorated(true);
                            admindashboardscreen.setLocationRelativeTo(null);
                            admindashboardscreen.setVisible(true);
                            setVisible(false);
                        }
                        else if(rs.getInt(2) == 2) {
                            
                            UserDashboard userdashboard = new UserDashboard();
                            
                            userdashboard.setUndecorated(true);
                            userdashboard.setLocationRelativeTo(null);
                            userdashboard.setVisible(true);
                            setVisible(false);
                        }
                        
                        
                    }else {
                        JOptionPane.showMessageDialog(null,"Invalid Account");
                    }
                
                    
                    sta.close();
                    
                }catch(Exception ex) {
                    System.out.println(ex.getMessage());
                }
                
            }
            
        }
    });

After I solved the first problem here is what happen after I add constructor to the UserDashboard Form the gui that I created is not showing.

Here is the real output without constructor

Thank you.

Answer 1

You are using Eclipse WindowBuilder. In order for custom classes to appear in the design view, each one must have a default, no-arguments constructor as stipulated in the JavaBeans specification. So give class AdminDashboardScreen and class UserDashboard two constructors: one default constructor – so that you can use the class in WindowBuilder – and another constructor that takes arguments which you need when running your application.