登录的确定和取消按钮为什么不出现。该如何处理

import java.awt.*;import java.awt.event.*;import javax.swing.*;public class Test_Login extends javax.swing.JFrame{    private JPanel jPanel1, jPanel2;    private JButton bntLogin;    private JButton bntCannel;    private JPasswordField pwd;    private JTextField username;    private JTextField computerid;    private JLabel jLabel2;    private JLabel jLabel3;    private JLabel jLabel1;    public Test_Login()    {        super();        initGUI();    }    private void initGUI()    {        try        {            setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);            {                getContentPane().setLayout(null);                jPanel1 = new JPanel();                jPanel2 = new JPanel();                getContentPane().add(jPanel1, BorderLayout.CENTER);                                jPanel1.setBounds(0, 0, 300, 150);                jPanel2.setBounds(0, 150, 300, 80);                jPanel2.setBackground(new java.awt.Color(102, 255, 204));                jPanel1.setLayout(null);                jLabel1 = new JLabel();                jLabel1.setText("用户名");                jLabel1.setBounds(45, 30, 75, 25);                jLabel2 = new JLabel();                jLabel2.setText("密码");                jLabel2.setBounds(45, 75, 55, 15);                username = new JTextField();                username.setBounds(100, 30, 140, 25);                pwd = new JPasswordField();                pwd.setBounds(100, 70, 140, 25);                jPanel1.add(jLabel1);                jPanel1.add(jLabel2);                jPanel1.add(username);                jPanel1.add(pwd);                // jPanel2.setLayout(new FlowLayout());//new FlowLayout                //jPanel2.setLayout(null);// new FlowLayout                bntLogin = new JButton();                bntLogin.setText("登陆");                //bntLogin.setBounds(0, 220, 60, 30);                bntCannel = new JButton();                bntCannel.setText("取消");                //bntCannel.setBounds(250, 220, 60, 30);                jPanel2.add(bntLogin);                jPanel2.add(bntCannel);                getContentPane().add(jPanel2, BorderLayout.SOUTH);                // jPanel2.add(bntLogin);                // jPanel2.add(bntCannel);                pack();                setSize(300, 230);                bntLogin.addMouseListener(new MouseAdapter()                {                    public void mouseClicked(MouseEvent e)                    {                        if (username.getText().equals("lisong")                                && pwd.getText().equals("lisong"))                        {                            JOptionPane.showMessageDialog(Test_Login.this,                                    "登录成功");                        } else                        {                            JOptionPane.showMessageDialog(Test_Login.this,                                    "登录失败");                        }                    }                });                bntCannel.addMouseListener(new MouseAdapter()                {                    public void mouseClicked(MouseEvent e)                    {                        System.exit(0);                    }                });            }        } catch (Exception e)        {            e.printStackTrace();        }    }    public static void main(String[] args)    {        Test_Login inst = new Test_Login();        inst.setLocationRelativeTo(null);        // inst.setResizable (false); //设置窗口不可放大缩小        inst.setVisible(true);    }}