loginframe.java

一个小型的考试系统,可以自行判断用户的得分

package com.ui;

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;

import javax.swing.*;

public class LoginFrame extends JFrame implements ActionListener{
	private JLabel jl;
	private JTextField jf;
	private JButton jb1;
	private JButton jb2;
	public LoginFrame()
	{
		super();
		JPanel top=new JPanel();
		jl=new JLabel("用户名：");
		jf=new JTextField(20);
		top.add(jl);
		top.add(jf);
		JPanel bottom=new JPanel();
		jb1=new JButton("登录");
		jb1.addActionListener(this);
		bottom.add(jb1);
		jb2=new JButton("退出");
		bottom.add(jb2);
		jb2.addActionListener(this);
//		this.getContentPane().add(jl);
//		this.getContentPane().add(jf);
//		this.getContentPane().add(jb1);
//		this.getContentPane().add(jb2);
		this.getContentPane().add(top,"North");
		this.getContentPane().add(bottom,"South");
//		this.setSize(350,150);
		this.setBounds(400, 300, 350, 150);
		this.setDefaultCloseOperation(3);
		this.setVisible(true);
	}
	public static void main(String[] args) {
		new LoginFrame();
	}
	public void actionPerformed(ActionEvent e) {
		if(e.getSource()==jb1)
		{
			File file=new File("txt\\user.txt");
			boolean isLoginSuccess=false;
			try {
				BufferedReader bf=new BufferedReader(new FileReader(file));
				String str="";
				while((str=bf.readLine())!=null)
				{
					if(str.equals(jf.getText().trim()))
					{
						isLoginSuccess=true;
					}
				}
				if(!isLoginSuccess)
				{
					jf.setText(null);
				    jf.grabFocus();
				}
				else
				{
					String user=jf.getText().trim();
					dispose();
					new MyJFrame(user);
				}
			} catch ( Exception e1) {
				// TODO 自动生成 catch 块
				e1.printStackTrace();
			}
		}
		// TODO 自动生成方法存根
		
	}
}