通过继承JFrame写一个类，该类中有一个隐藏当前FRAME的按钮，请问该如何编写该按钮的代码？

Question

通过继承JFrame写一个类，该类中有一个隐藏当前FRAME的按钮，请问该如何编写该按钮的代码？具体代码如下：class RegFrame extends JFrame
{
    public RegFrame()
    {
        setTitle("用户注册");
        setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
        Toolkit kit=Toolkit.getDefaultToolkit();
        Dimension screenSize=kit.getScreenSize();
        setLocation(screenSize.width/4,screenSize.height/4);
        Container contentPane=getContentPane();
        okButton=new JButton("注册");
        calButton=new JButton("取消");
                JPanel buttonPanel=new JPanel();
        buttonPanel.add(okButton);
        buttonPanel.add(calButton);
        contentPane.add(buttonPanel,BorderLayout.SOUTH);
        ActionListener okAction=new RegFrame.okAction();
        ActionListener calAction=new RegFrame.calAction();
        calButton.addActionListener(calAction);
        okButton.addActionListener(okAction);
        inputPanel=new JPanel();
        inputPanel.setLayout(new GridLayout(0,2));
        contentPane.add(inputPanel,BorderLayout.CENTER);
        
        usernameText=new JTextField();
        passwordText=new JPasswordField();
        usersexText=new JTextField();
        
        JLabel userLabel=new JLabel("用户名：");
        JLabel passLabel=new JLabel("密　码：");
        JLabel sexLabel=new JLabel("性　别：");
        
        inputPanel.add(userLabel);
        inputPanel.add(usernameText);
        inputPanel.add(passLabel);
        inputPanel.add(passwordText);
        inputPanel.add(sexLabel);
        inputPanel.add(usersexText);
    }
    private class okAction implements ActionListener
    {
        
        public void actionPerformed(ActionEvent e) 
        {
                try {
       Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
      //Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
      String url ="jdbc:microsoft:sqlserver://192.168.0.86;DatabaseName=mmc";
      //Test为你的数据库的
      String user = "sa";
      String password = "";
      Connection conn = DriverManager.getConnection(url, user, password);
      Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
      String username=usernameText.getText();
      String spassword=new String(passwordText.getPassword());
      String ssex=usersexText.getText();
           
      String sql = "Insert mmc(username,userpwd,usersex) values('"+username+"','"+spassword+"','"+ssex+"')";
      stmt.execute(sql);
      stmt.close();
      conn.close();
      //JOptionPane.showMessageDialog(null,"注册成功！",JOptionPane.INFORMATION_MESSAGE,null);
      JOptionPane.showMessageDialog(null,"注册成功！","用户注册",JOptionPane.INFORMATION_MESSAGE);    }
    catch (Exception ee) {
    System.out.println(ee);
    JOptionPane.showMessageDialog(null,"出错了！","用户注册",JOptionPane.INFORMATION_MESSAGE);
    }
        }
        
    }
    private class calAction implements ActionListener
    {
        
        public void actionPerformed(ActionEvent e2) 
        {
            //这里写代码隐藏该FRAME，如何写？
            //这里写代码隐藏该FRAME，如何写？
            //这里写代码隐藏该FRAME，如何写？
            //这里写代码隐藏该FRAME，如何写？
            //这里写代码隐藏该FRAME，如何写？
            //这里写代码隐藏该FRAME，如何写？
            //这里写代码隐藏该FRAME，如何写？
            //这里写代码隐藏该FRAME，如何写？
            
        }
        
    }
    public static final int DEFAULT_WIDTH=200;
    public static final int DEFAULT_HEIGHT=170;
    private JButton okButton;
    private JButton calButton;
    private JPanel inputPanel;
    private JTextField usernameText;
    private JTextField usernameText2;
    private JPasswordField passwordText;
    private JTextField usersexText;
    
}