login.java

简单的银行管理

import javax.swing.*;
import java.awt.event.*;
import java.awt.Toolkit;


public class Login extends JFrame implements ActionListener {
 
 JLabel _name,_password;
 JButton _logon,_exit;
 JTextField _jtfname;
 JPasswordField _jtfpassword;
 JPanel _jpname,_jppassword,_jpbutton;
 
    public Login() {
     super("欢迎登录");
     _name   =   new JLabel("用户名:");
     _password = new JLabel("密    码:");
     _logon = new JButton("登录");
     _logon.addActionListener(this);
     _exit  = new JButton("退出");
     _exit.addActionListener(this);
     _jtfname = new JTextField(8);
     _jtfpassword = new JPasswordField(8);
     _jpname = new JPanel();
     _jppassword = new JPanel();
     _jpbutton = new JPanel();
     
     _jpname.add(_name);
     _jpname.add(_jtfname);
     
     _jppassword.add(_password);
     _jppassword.add(_jtfpassword);
     
     _jpbutton.add(_logon);
     _jpbutton.add(_exit);
     
     add(_jpname,"North");
     add(_jppassword);
     add(_jpbutton,"South");
     
     pack();
     setVisible(true);
    int W = (int)Toolkit.getDefaultToolkit().getScreenSize().getWidth();
    int H = (int)Toolkit.getDefaultToolkit().getScreenSize().getHeight();
    this.setLocation((W-this.getWidth())/2,(H-this.getHeight())/2);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    
    public static void main (String[] args) {
     new Login(); 
 }
 public void actionPerformed(ActionEvent e){
  if(e.getSource()==_logon){
   String username = _jtfname.getText().trim();
      String password = new String(_jtfpassword.getPassword()).trim();
      DB db = new DB();
      if(db.login(username,password)){
       JOptionPane.showMessageDialog(this,"登录成功");
       new Select(username,password);
       this.dispose();
      }
      else
      {
       JOptionPane.showMessageDialog(this,"登录失败，请确认您的输入正确!"+"/n"+"或者已经成功连接数据库!!!");
      }
  }
  if(e.getSource()==_exit){
   System.exit(0);
  }
 }
}