login.java

是一个简化的学校教职工管理系统

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

public class Login extends JFrame implements ActionListener{
     
	JLabel j1,j2;
	JPasswordField jf_passwd;
	JTextField jf_user;
	JButton jb_ok,jb_exit;
	int count=0;
	boolean isLaw=false;
	public Login(){
		
		j1=new JLabel("user:");
		j2=new JLabel("password:");
		jf_user=new JTextField();
		jf_passwd=new JPasswordField('*');
		jb_ok=new JButton("OK");
		jb_exit=new JButton("EXIT");
		
		jb_ok.addActionListener(this);
		jb_exit.addActionListener(this);
		
		Container c=this.getContentPane();
		c.setLayout(new GridLayout(3,2));
		c.add(j1);c.add(jf_user);
		c.add(j2);c.add(jf_passwd);
		c.add(jb_ok);c.add(jb_exit);
		
		this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
		setTitle("please login first!");
		setSize(300,100);
		//pack();
		setVisible(true);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		
		
	}
	
	

	public void actionPerformed(ActionEvent e) {
		
		if(e.getActionCommand().equals("OK")){
			
			try{

				String user=jf_user.getText();
				String passwd=MD5.md5(jf_passwd.getText());
				
				File file=new File("code.caa");
				BufferedReader bf=new BufferedReader(new FileReader(file));
				
				
				String line;
				isLaw=false;
				while((line=bf.readLine())!=null){
					int pos=line.indexOf(":");
					String sub=line.substring(0, pos);
					
					//System.out.println(sub);
					String sub2=line.substring(pos+1, line.length());
					//System.out.println(sub2);
					if(sub.equalsIgnoreCase(user)){
						
						
						if(sub2.equalsIgnoreCase(passwd)){
							isLaw=true;
							break;
						}
							
						
							
						
					}
					
				}
				
				
				if(isLaw){
					JOptionPane.showMessageDialog(this, "成功登陆！");
					new DBControler();
					this.dispose();
					
				}
				else{
					JOptionPane.showMessageDialog(this, "用户名或密码错误！");
					count++;
					if(count>=3){
						JOptionPane.showMessageDialog(this, "三次尝试错误，系统将退出！");
						System.exit(0);
						
					}
					
					
				}
					//JOptionPane.showMessageDialog(this, "用户名或密码错误！");
					
					
			}catch(IOException e1){
				
				JOptionPane.showMessageDialog(null, e1.getMessage());
			}
		}
		else {
			
			if(e.getActionCommand().equals("EXIT"))
				System.exit(0);
		}
		
		
	}
    public static void main(String[] args) {
		
                new Login();
	}

}