userlogin.java

一个图书管理系统

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


public class UserLogin extends JFrame implements ActionListener{
	DataBaseManager db=new DataBaseManager();
	MainWindow mainFrame;
	JPanel panel1,panel2;
	JLabel UserLabel,PasswordLabel;
	JTextField UserTextField;
	JPasswordField PasswordTextField;
	JButton YesBtn,CancelBtn;
	Container c;
	ResultSet rs;
	public UserLogin(MainWindow mainFrame)
	{
		super("用户登陆");
		this.mainFrame=mainFrame;
		UserLabel=new JLabel("用户名",JLabel.CENTER);
		PasswordLabel=new JLabel("密码",JLabel.CENTER);
		UserTextField=new JTextField(10);
		PasswordTextField=new JPasswordField(10);
		YesBtn=new JButton("确定");
		CancelBtn=new JButton("取消");
		YesBtn.addActionListener(this);
		CancelBtn.addActionListener(this);
		
		panel1=new JPanel();
		panel1.setLayout(new GridLayout(2,2));
		panel2=new JPanel();
		c=getContentPane();
		c.setLayout(new BorderLayout());
		panel1.add(UserLabel);
		panel1.add(UserTextField);
		panel1.add(PasswordLabel);
		panel1.add(PasswordTextField);
		c.add(panel1,BorderLayout.CENTER);
		panel2.add(YesBtn);
		panel2.add(CancelBtn);
		c.add(panel2,BorderLayout.SOUTH);
		setSize(300,300);
	}

    public void actionPerformed(ActionEvent e)
    {
    	if(e.getSource()==CancelBtn)
    	{
    	
    		this.dispose();
    	}
    	else
    	{
    		char[] password=PasswordTextField.getPassword();
    		String passwordSTR=new String(password);
    		if(UserTextField.getText().trim().equals(""))
    		{
    			JOptionPane.showMessageDialog(null,"用户名不可为空!");
    			return;
    		}
    		if(passwordSTR.equals(""))
    		{
    			JOptionPane.showMessageDialog(null,"密码不可为空!");
    			return;
    		}
    		
    		String strSQL;
    		strSQL="select * from authors";
    		rs=db.getResult(strSQL);
    		boolean isExist=false;
    		try
    		{
    			isExist=rs.first();
    			
    		}
    	catch(SQLException sqle)
			{
				System.out.println(sqle.toString());
			}
			if(!isExist)
			{
				JOptionPane.showMessageDialog(null,"用户名不存在或者密码不正确!");
		
			}
			else
			{
				try
				{
					rs.first();
					mainFrame.setEnable(rs.getString("power").trim());
					db.closeConnection();
					this.dispose();
				}
				catch(SQLException sqle2)
				{
					System.out.println(sqle2.toString());
				}
			}
    	}
    }
    
}