userlogin.java

java 开发的图书管理系统~~~。可以实现很多功能

package bookmanager;
import java.sql.*;

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

 public class userLogin extends JFrame implements ActionListener{
	public userLogin(BookManagerMain bMain)
	{
		myBook=bMain;
		setTitle("用户登陆");
		JPanel panel1=new JPanel();
		panel1.setSize(100,200);
		panel1.setLayout(new GridLayout(3,2,20,20));
		userlbl=new JLabel("用户名");
		passwordlbl=new JLabel("密码");
		usertex=new JTextField("");
		passwordtex=new JPasswordField("");
		surebtn=new JButton("确定");
		cancelbtn=new JButton("取消");
		panel1.add(userlbl);
		panel1.add(usertex);
		panel1.add(passwordlbl);
		panel1.add(passwordtex);
		panel1.add(surebtn);
		panel1.add(cancelbtn);
		getContentPane().add(panel1);
		surebtn.addActionListener(this);
		cancelbtn.addActionListener(this);
	} 
	public void actionPerformed(ActionEvent e)
	{
		Object source=e.getSource();
		if(source==surebtn)
		{
			if(usertex.getText().trim().equals(""))
			{
			JOptionPane.showMessageDialog(null,"用户名不能为空!");
			return;
		}
		if(new String(passwordtex.getPassword()).trim().equals(""))
		{
			JOptionPane.showMessageDialog(null,"密码名不能为空!");
			return;
		}
		String strsql;
		//查询密码与用户名匹配的一项
		strsql=("select * from admin where Username='"+usertex.getText().trim()+"'and Password='"+(new String(passwordtex.getPassword()).trim())+"'");
		rs=db.getResult(strsql);
		
		boolean isexist=false;
		try{
			//把游标指向结果集的第一行，如果没有数据则返回false
			isexist=rs.first();		
		}
		catch(SQLException w)
		{
			System.out.println(w);}
		//判断结果是否正确
		if(!isexist){
			JOptionPane.showMessageDialog(null,"用户名不存在,或密码不正确");
			myBook.setEnabled("else");
		}
		else{
			try{
				rs.first();
				myBook.setEnabled(rs.getString("power").trim());
				this.dispose();
			}
			catch(SQLException es){
			}
		}
		if(source==cancelbtn)
		{
			myBook.setEnabled("");
			this.dispose();
			return;
		}
	}
		/*
			String user=usertex.getText();
			ch=passwordtex.getPassword();
			String password=new String(ch);
			if(user.trim().equals(""))
			{
			JOptionPane.showMessageDialog(null,"用户名不能为空!");
			return;
		}
		if(password.trim().equals(""))
		{
			JOptionPane.showMessageDialog(null,"密码名不能为空!");
			return;
		}
			if(user.equals("admin")&&password.equals("admin"))
			{
				myBook.setEnabled("管理员");
			}
			if(user.equals("borrowcontrol")&&password.equals("borrowcontrol"))
			{
				myBook.setEnabled("借阅操作员");
			}
			if(user.equals("bookcontrol")&&password.equals("bookcontrol"))
			{
				myBook.setEnabled("书籍管理员");
			}
			this.dispose();
		}*/
		if(source==cancelbtn)
		{
			myBook.setEnabled("");
			this.dispose();
			return;
		}
		}
//	private ResultSet rs;
//	private DBManager db=DBManager();
	private BookManagerMain myBook;
	private JLabel userlbl;
	private JLabel passwordlbl;
	private JTextField usertex;
	private JPasswordField passwordtex;
	private JButton surebtn;
	private JButton cancelbtn;
	private GridLayout gl;
	private char[] ch;
	private ResultSet rs;
	private DBManager db=new DBManager();
}