请编程设计一个登陆界面，要求输入账号和密码(不考虑事件)

import  java.awt.Container;
import  java.awt.FlowLayout;
import  java.awt.GridLayout;
import  java.awt.event.ActionEvent;
import  java.awt.event.ActionListener;

import  javax.swing.JButton;
import  javax.swing.JFrame;
import  javax.swing.JLabel;
import  javax.swing.JTextField;

public  class  dengru  extends  JFrame  implements  ActionListener {

    private  static  final  long  serialVersionUID = 1L;

    private  Container c =  null ;
    private  JButton jb =  null ;

    public  dengru() {
        this .setLayout( new  FlowLayout());
        jb =  new  JButton( "登入" );
        jb.addActionListener( this );
        this .add(jb);
        this .setSize( 500 ,  400 );
        this .setVisible( true );
        this .setDefaultCloseOperation(DISPOSE_ON_CLOSE);
    }

    public  static  void  main(String[] args) {
              new   dengru();
    }

    @Override
    public  void  actionPerformed(ActionEvent e) {
        if  (e.getSource() == jb) {
            JFrame jf= new  JFrame();
            c = jf.getContentPane();
            c.setLayout( new  GridLayout( 3 , 2 , 2 , 2 ));
            JLabel jl1 =  new  JLabel( "用户名：" );
            JLabel jl2 =  new  JLabel( "密    码：" );
            JTextField jtf1 =  new  JTextField();
            JTextField jtf2 =  new  JTextField();
            jtf1.setSize( 200 ,  40 );
            jtf2.setSize( 200 ,  40 );
            c.add(jl1);
            c.add(jtf1);
            c.add(jl2);
            c.add(jtf2);
            c.add( new  JButton( "登入" ));
            jf.setVisible( true );
            jf.setSize( 300 ,  100 );
            jf.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
        }
    }
}