import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
/**
 *
 * @author FC
 */
public class LoginPanel extends JFrame {
    JPanel panel=new JPanel();
    JLabel label1=new JLabel("用户名");
    JLabel label2=new JLabel("密码");
    JTextField field1=new JTextField(10);
    JPasswordField field2=new JPasswordField(10);
    JButton btl1=new JButton("登陆");
    JButton btl2=new JButton("取消");
    JButton btl3=new JButton("重填"); 
    public LoginPanel() {
        this.initb();
    }
    public void initb(){
     
        this.getContentPane().add(panel);
        panel.add(label1);
        panel.add(field1);
        panel.add(label2);
        panel.add(field2);
        panel.add(btl1);
        panel.add(btl2);
        panel.add(btl3);
        MyActionListener ma=new MyActionListener();
        btl1.addActionListener(ma);
        btl3.addActionListener(new MyActionListener());
    }
    class MyActionListener implements ActionListener{
        public void actionPerformed(ActionEvent e){ 
            Object obj=e.getSource();
            if(obj==btl1){
                if(field1.getText().length()==0){
                    JOptionPane.showMessageDialog(null ,"用户名不能为空");
                }
                if(field2.getPassword().length()==0){
                    JOptionPane.showMessageDialog(null,"密码不能为空");
                }
               
                else {
                    JOptionPane.showMessageDialog(null,"即将转入页面，请稍候");
                }
            }
            else if(obj==btl3){
                field1.setText("");
                field2.setText("");
            }
        }
    }
    public void displayDetails(){
      this.show();
      this.setSize(400, 400);
      this.setDefaultCloseOperation(3);
    }
    public static void main(String args[]){
      LoginPanel p=new LoginPanel();
       p.displayDetails();
    }
 
}