为什么joptionpane popup两次

Question

I have two problem now. My First Problem is when i click the confirm button, it will insert the data two times into ms access database. My Second Problem is why joptionpane also popup two times.

I have the main login page when open the program. When i click the sign up button, it will remove all the component inside the center jpanel. Then it will add again component to use in registration form like jtextfield,jlabel,icon for username,password,tel no and others.I already checked, that the statement to execute insert statement and joptionpanes only have one times only.

This is the full code of my program

package userForm;

    import java.sql.*;
    import java.util.logging.Handler;
    import javax.swing.*;
    import javax.swing.border.Border;
    import javax.swing.border.EmptyBorder; 
    import java.awt.*;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;

    public class loginForm extends JFrame implements ActionListener{

    private JPanel centerPanel,bottomPanel;
    private JLabel titleLabel, descriptionLabel;
    private JLabel usernameLabel, passwordLabel, signInLabel, iconUsername, iconPassword;
    private JLabel signUpLabel, fullNameLabel, staffIDLabel, usernameRegLabel, passwordRegLabel, telNoLabel, emailLabel;
    private JLabel iconFullName, iconStaffID, iconUsernameReg, iconPasswordReg, iconTelNo, iconEmail;
    private JTextField usernameField, fullNameField, staffIDField, usernameRegField,  telNoField, emailField;
    private JPasswordField passwordField, passwordRegField;
    private JButton loginButton, signUpButton,confirmButton,exitButton;
    private String username;
    private String password;
    userDatabase db;
    userDatabase db1;
    handler handle;

    public loginForm(String title) {

        db=new userDatabase();
        handle =new handler();

        //create label to use in topPanel
        titleLabel = new JLabel("ABC Burger Inventory System");
        titleLabel.setFont(new Font("Calibri", Font.TRUETYPE_FONT, 23));
        titleLabel.setForeground(Color.white);
        Border empty = new EmptyBorder(30, 20, 0, 0);
        titleLabel.setBorder(empty);
        descriptionLabel = new JLabel("Please Login To Use This System");
        Border empty1 = new EmptyBorder(-30, 20, 0, 0);
        descriptionLabel.setBorder(empty1);
        descriptionLabel.setFont(new Font("Calibri", Font.HANGING_BASELINE, 14));
        descriptionLabel.setForeground(Color.white);

        //create label to use in centerPanel
        signInLabel = new JLabel("SIGN IN");
        usernameLabel = new JLabel("Username:");
        passwordLabel = new JLabel("Password");

        //create textfield to use in center Panel
        usernameField = new JTextField("Required");

        passwordField = new JPasswordField("Required");

        //create label to use in registration form
        signUpLabel = new JLabel("SIGN UP");
        fullNameLabel = new JLabel("Full Name:");
        staffIDLabel = new JLabel("Staff ID:");
        usernameRegLabel = new JLabel("Username:");
        passwordRegLabel = new JLabel("Password");
        telNoLabel = new JLabel("Tel No:");
        emailLabel = new JLabel("Email:");

        //create textfield to use in registration form
        fullNameField = new JTextField(30);
        staffIDField = new JTextField(30);
        usernameRegField = new JTextField(30);
        passwordRegField = new JPasswordField(30);
        telNoField = new JTextField(30);
        emailField = new JTextField(30);


        //create button to use in bottom Panel
        loginButton = new JButton("Login");
        signUpButton = new JButton("Sign Up");
        confirmButton = new JButton("Confirm");
        confirmButton.addActionListener(this);
        exitButton = new JButton("Exit");
        exitButton.addActionListener(this);

        //create panel to use in frame
        topPanelWithBackground topPanel = new topPanelWithBackground();
        topPanel.setLayout(new GridLayout(2,1));
        centerPanel = new JPanel();
        centerPanel.setLayout(null);
        bottomPanel = new JPanel();
        bottomPanel.setLayout(new FlowLayout(FlowLayout.CENTER, 40, 10));

        //add component to top panel
        topPanel.add(titleLabel);
        topPanel.add(descriptionLabel);

        //add component to center panel
        signInLabel.setBounds(270, 30, 100, 20);
        signInLabel.setFont(new Font("Calibri", Font.TRUETYPE_FONT, 20));
        centerPanel.add(signInLabel);

        usernameLabel.setBounds(200, 60, 100, 20);
        usernameLabel.setFont(new Font("Calibri", Font.BOLD, 14));
        centerPanel.add(usernameLabel);

        ImageIcon imageUser = new ImageIcon("user.png");
        iconUsername = new JLabel(imageUser, JLabel.CENTER);
        iconUsername.setBounds(160, 90, 32, 32);
        centerPanel.add(iconUsername);

        usernameField.setBounds(200, 90, 200, 32);
        usernameField.setFont(new Font("Calibri", Font.BOLD, 14));
        centerPanel.add(usernameField);

        passwordLabel.setBounds(200, 140, 100, 20);
        passwordLabel.setFont(new Font("Calibri", Font.BOLD, 14));
        centerPanel.add(passwordLabel);

        ImageIcon imagePassword = new ImageIcon("password.png");
        iconUsername = new JLabel(imagePassword, JLabel.CENTER);
        iconUsername.setBounds(160, 170, 32, 32);
        centerPanel.add(iconUsername);

        passwordField.setBounds(200, 170, 200, 32);
        passwordField.setFont(new Font("Calibri", Font.BOLD, 14));
        centerPanel.add(passwordField);

        loginButton.setFont(new Font("Calibri", Font.BOLD, 14));
        loginButton.addActionListener(handle);
        bottomPanel.add(loginButton);

        signUpButton.setFont(new Font("Calibri", Font.BOLD, 14));
        signUpButton.addActionListener(this);
        bottomPanel.add(signUpButton);

        //add confirm button
        exitButton.setFont(new Font("Calibri", Font.BOLD, 14));
        exitButton.addActionListener(this);
        bottomPanel.add(exitButton);

        getContentPane().setLayout(new BorderLayout());
        getContentPane().add(topPanel, BorderLayout.NORTH );
        getContentPane().add(centerPanel, BorderLayout.CENTER);
        getContentPane().add(bottomPanel, BorderLayout.SOUTH);


        //frame behaviour
        super.setTitle(title);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//exit
        setSize(600,500);

    }

        class handler implements ActionListener{
            public void actionPerformed(ActionEvent as) {
                if(as.getSource()==loginButton){
                    centerPanel.removeAll(); 
                    centerPanel.revalidate();
                    centerPanel.repaint();
                    //add component to center panel
                    signInLabel.setBounds(270, 30, 100, 20);
                    signInLabel.setFont(new Font("Calibri", Font.TRUETYPE_FONT, 20));
                    centerPanel.add(signInLabel);

                    usernameLabel.setBounds(200, 60, 100, 20);
                    usernameLabel.setFont(new Font("Calibri", Font.BOLD, 14));
                    centerPanel.add(usernameLabel);

                    ImageIcon imageUser = new ImageIcon("user.png");
                    iconUsername = new JLabel(imageUser, JLabel.CENTER);
                    iconUsername.setBounds(160, 90, 32, 32);
                    centerPanel.add(iconUsername);

                    usernameField.setBounds(200, 90, 200, 32);
                    usernameField.setFont(new Font("Calibri", Font.BOLD, 14));
                    centerPanel.add(usernameField);

                    passwordLabel.setBounds(200, 140, 100, 20);
                    passwordLabel.setFont(new Font("Calibri", Font.BOLD, 14));
                    centerPanel.add(passwordLabel);

                    ImageIcon imagePassword = new ImageIcon("password.png");
                    iconUsername = new JLabel(imagePassword, JLabel.CENTER);
                    iconUsername.setBounds(160, 170, 32, 32);
                    centerPanel.add(iconUsername);

                    passwordField.setBounds(200, 170, 200, 32);
                    passwordField.setFont(new Font("Calibri", Font.BOLD, 14));
                    centerPanel.add(passwordField);

                    char[] temp_pwd=passwordField.getPassword();
                    String pwd=null;
                    pwd=String.copyValueOf(temp_pwd);
                    System.out.println("Username,Pwd:"+usernameField.getText()+","+pwd);

                    //The entered username and password are sent via "checkLogin()" which return boolean
                    if(db.checkLogin(usernameField.getText(), pwd))
                    {
                        newFrame regFace =new newFrame();
                        regFace.setVisible(true);
                        dispose();
                    }
                    else if(usernameField.getText().equals("") || passwordField.getText().equals("")){
                        JOptionPane.showMessageDialog(null, "Please fill out the form","Error!!",
                                JOptionPane.ERROR_MESSAGE);
                    }
                    else
                    {
                        //a pop-up box
                        JOptionPane.showMessageDialog(null, "Login failed!","Failed!!",
                                            JOptionPane.ERROR_MESSAGE);
                    }
                }

            }
             }

        @Override
        public void actionPerformed(ActionEvent ae) {
            if(ae.getSource()==signUpButton){
                centerPanel.removeAll(); 
                        //sign up label
                signUpLabel.setBounds(270, 30, 100, 20);
                signUpLabel.setFont(new Font("Calibri", Font.TRUETYPE_FONT, 20));
                centerPanel.add(signUpLabel);

                //fullname label,icon and field
                fullNameLabel.setBounds(80, 60, 100, 20);
                fullNameLabel.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(fullNameLabel);

                ImageIcon imageFullname = new ImageIcon("fullname.png");
                iconUsernameReg = new JLabel(imageFullname, JLabel.CENTER);
                iconUsernameReg.setBounds(40, 90, 32, 32);
                centerPanel.add(iconUsernameReg);

                fullNameField.setBounds(80, 90, 200, 32);
                fullNameField.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(fullNameField);

                //staffID label,icon and field
                staffIDLabel.setBounds(80, 140, 100, 20);
                staffIDLabel.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(staffIDLabel);

                ImageIcon imageStaffID = new ImageIcon("staffID.png");
                iconStaffID = new JLabel(imageStaffID, JLabel.CENTER);
                iconStaffID.setBounds(40, 170, 32, 32);
                centerPanel.add(iconStaffID);

                staffIDField.setBounds(80, 170, 200, 32);
                staffIDField.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(staffIDField);

                //usernameReg label,icon and field          
                usernameRegLabel.setBounds(80, 220, 100, 20);
                usernameRegLabel.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(usernameRegLabel);

                ImageIcon imageUsernameReg = new ImageIcon("user.png");
                iconUsernameReg = new JLabel(imageUsernameReg, JLabel.CENTER);
                iconUsernameReg.setBounds(40, 250, 32, 32);
                centerPanel.add(iconUsernameReg);

                usernameRegField.setBounds(80, 250, 200, 32);
                usernameRegField.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(usernameRegField);

                //passwordReg label,icon and field          
                passwordRegLabel.setBounds(350, 60, 100, 20);
                passwordRegLabel.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(passwordRegLabel);

                ImageIcon imagePasswordReg = new ImageIcon("password.png");
                iconPasswordReg = new JLabel(imagePasswordReg, JLabel.CENTER);
                iconPasswordReg.setBounds(310, 90, 32, 32);
                centerPanel.add(iconPasswordReg);

                passwordRegField.setBounds(350, 90, 200, 32);
                passwordRegField.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(passwordRegField);

                //telNo label,icon and field            
                telNoLabel.setBounds(350, 140, 100, 20);
                telNoLabel.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(telNoLabel);

                ImageIcon imagetelNo = new ImageIcon("phone.png");
                iconTelNo = new JLabel(imagetelNo, JLabel.CENTER);
                iconTelNo.setBounds(310, 170, 32, 32);
                centerPanel.add(iconTelNo);

                telNoField.setBounds(350, 170, 200, 32);
                telNoField.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(telNoField);

                //Email label,icon and field            
                emailLabel.setBounds(350, 220, 100, 20);
                emailLabel.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(emailLabel);

                ImageIcon imageEmail = new ImageIcon("mail.png");
                iconEmail  = new JLabel(imageEmail , JLabel.CENTER);
                iconEmail .setBounds(310, 250, 32, 32);
                centerPanel.add(iconEmail );

                emailField.setBounds(350, 250, 200, 32);
                emailField.setFont(new Font("Calibri", Font.BOLD, 14));
                centerPanel.add(emailField);

                //add confirm button
                confirmButton.setFont(new Font("Calibri", Font.BOLD, 14));
                confirmButton.addActionListener(this);
                bottomPanel.add(confirmButton);     

                centerPanel.revalidate();
                centerPanel.repaint();

            }
            else if(ae.getSource()==confirmButton){
                char[] temp_pwd1=passwordRegField.getPassword();
                String pwd=null;
                pwd=String.copyValueOf(temp_pwd1);
                if(fullNameField.getText().equals("") || staffIDField.getText().equals("") || usernameRegField.getText().equals("") ||  passwordRegField.getPassword().length == 0 ||  telNoField.getText().equals("") || emailField.getText().equals("")){
                    JOptionPane.showMessageDialog(null, "Please Fill Out Any Field", "Error",
                            JOptionPane.ERROR_MESSAGE);
                }
                else {
                db1 = new userDatabase();
                try {
                    db1.insertData(fullNameField.getText(), staffIDField.getText(), usernameRegField.getText(), pwd, telNoField.getText(), emailField.getText());
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                }
            }
            else if(ae.getSource()==exitButton){
                System.exit(0);
            }
        }

}

Answer 1

When you click the sign up button you are adding listener to the confirm button again. So when you click the confirm button it is executed twice.

Remove the following line in the actionPerformed method of LoginForm

confirmButton.addActionListener(this);