login.java

7、学生学籍管理系统 调查所在学校学生处、教务处

package file;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
/***
 * 
 * 
 * *系统的登陆界面**/
public class Login extends JFrame implements ActionListener,KeyListener{

	private JLabel l1,l2,l3;
	private JTextField text1;
	private JPasswordField text2;
	private JButton b1,b2;
	private JPanel p1,p2,p3,p4,p5;
	private Container c;
	
	public Login()
	{
		super("学生成绩管理系统--登陆");
	    c=this.getContentPane();
	    this.setResizable(true);
		//set frame in center
    	int x,y;
    	x=(int)(Toolkit.getDefaultToolkit()).getScreenSize().getWidth();
    	y=(int)(Toolkit.getDefaultToolkit()).getScreenSize().getHeight();
    	this.setLocation(x/2-250,y/2-300);
    	this.setSize(350,300);
    	//end
    	p1=new JPanel();
    	p2=new JPanel();
    	p3=new JPanel();
    	p4=new JPanel();
    	p5=new JPanel();
    	
    	l1=new JLabel("管理员登陆",JLabel.CENTER);
    	l2=new JLabel("密码：",JLabel.CENTER);
    	l3=new JLabel("用户名：",JLabel.CENTER);
    	b1=new JButton("确定");
    	b2=new JButton("重置");
    	b1.addActionListener(this);
    	b2.addActionListener(this);
    	//请输入用户名密码
    	text1=new JTextField();
    	//text1.setSize(5,5);
    	
    	text2=new JPasswordField();
    	text1.setPreferredSize(new Dimension(3,0));
    	text1.requestFocus();
    	text1.addKeyListener(this);
    	text2.addKeyListener(this);
    	l1.setPreferredSize(new Dimension(190,50));
        l1.setForeground(new Color(204,0,153));
        Font titleLabelFont = new Font("Dialog",Font.BOLD,18);
        l1.setFont(titleLabelFont);
        text1.setPreferredSize(new Dimension(10,20));
        p1.setLayout(new GridLayout(3,1));
    	p1.add(l1);
    	p2.setLayout(new GridLayout(2,1));
    	p2.add(l3);
    	p2.add(l2);
    	p3.setLayout(new GridLayout(2,1));
    	p3.add(text1);
    	p3.add(text2);
    	p4.setLayout(new FlowLayout());
    	p4.add(b1);
    	p4.add(b2);
    	p5.setLayout(new GridLayout(1,2));
    	p5.add(p2);
    	p5.add(p3);
    	
    
     	p1.add(p5);
    	p1.add(p4,BorderLayout.WEST);
    	
    	c.setLayout(new GridLayout(1,1));
    	c.add(p1);
    	this.setResizable(false);
    	
	
		
	}
	
	public void check()
	{
		String username=text1.getText();
		String password=text2.getText();
		if(username==null || password==null || username.equals("") || password.equals(""))
		{
			JOptionPane.showMessageDialog(null,"       请正确输入! ");
			text2.setText(null);
			
		}
		else
		{
			//check
			Operate_db temp_db=new Operate_db();
			if(temp_db.login_check(username, password))
			{
				this.hide();
				JOptionPane.showMessageDialog(null,"     欢迎"+username+"登陆本系统!");
				MainFrame sf=new MainFrame();
				sf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
				sf.show();
			}
			else
			{
				JOptionPane.showMessageDialog(null,"用户名或密码错误!\n登陆失败,请重新登陆!");
				text1.setText(null);
				text2.setText(null);
			}
			temp_db.close();
		}
	}
	
	public void keyTyped(KeyEvent e)
	{	
	}
	public void keyPressed(KeyEvent e)
	{
		if(e.getKeyChar()=='\n')
		{
			check();
		}
			
	}
	public void keyReleased(KeyEvent e)
	{}
	
	public void actionPerformed(ActionEvent e)
	{
		JButton temp=(JButton)e.getSource();
		
		if(temp==b1)
		{
			check();
		}
		else if(temp==b2)
		{
			text1.setText(null);
			text2.setText(null);
			
		}
	}

}