程序代码：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class MyFieldExample extends JFrame implements ActionListener
{
    JLabel JL1,JL2,JL3;
    JButton JB1,JB2;
    JTextField JF1;
    JPasswordField JP1;
    public MyFieldExample()
    {
        super("登录界面");
        JL1=new JLabel("用户名称");
        JL1.setBounds(15,5,60,20);
        JL2=new JLabel("登录密码");
        JL2.setBounds(15,25,60,20);
        JF1=new JTextField("",20);
        JF1.setBounds(110,5,100,20);
        JP1=new JPasswordField("",20);
        JP1.setBounds(110,25,100,20);
        JB1=new JButton("确定");
        JB1.setBounds(35,50,60,30);
        JB1.addActionListener(this);
        JB2=new JButton("取消");
        JB2.setBounds(130,50,60,30);
        JB2.addActionListener(this);
        JL3=new JLabel("");
        JL3.setBounds(60,90,200,30);
        Container winContainer=this.getContentPane();
        winContainer.setLayout(null);
        winContainer.add(JL1);
        winContainer.add(JL2);
        winContainer.add(JB1);
        winContainer.add(JB2);
        winContainer.add(JL3);
        winContainer.add(JF1);
        winContainer.add(JP1);
        this.setSize(250,150);
        this.setVisible(true);
     }
     public static void main(String args[])
     {
         MyFieldExample w1=new MyFieldExample();
        
     }
     public void actionPerformed(ActionEvent e)
     {
         if(e.getSource()==JB1)
         {
             if(JF1.getText().equals("JAVA")&&JP1.getText().equals("1234"))
             JL3.setText("输入正确，登录成功");
             else
             JL3.setText("输入错误，请重新输入");
         }
         else if
         (e.getSource()==JB2)
          System.exit(0);
       
     }
       
       
       
       
    }