login.java

来自「用纯java语言实现的数字证书制作工具。」· Java 代码 · 共 113 行

package data;
import java.awt.*;
import java.sql.*;
import java.awt.event.*;
import javax.swing.*;
import data.MyWindowListener;
import data.Connect;


public class Login extends JFrame implements ActionListener
{
	private JTextField user;
	private JPasswordField pwd;
	private JButton ok;
	private JButton cancel;
	
	public  Login() 
	{
		super("用户查询登录界面");
		Container c=getContentPane();
		c.setLayout(new FlowLayout());
		user=new JTextField(10);
		c.add(new JLabel("用户名称："));
		c.add(user);
		pwd=new JPasswordField(10);
		c.add(new JLabel("用户密码："));
		c.add(pwd);
		
		ok=new JButton("OK");
		c.add(ok);
		cancel=new JButton("Reset");
		c.add(cancel);
		setSize(220,130);
		setVisible(true);
		ok.addActionListener(this);
		cancel.addActionListener(this);
	}
	public void actionPerformed(ActionEvent e)
	{
		if(e.getSource()==ok) 
		{
			String query;
			String name,pass,msg;
			name=user.getText().trim();
			pass=pwd.getText().trim();
			if(name.equals(""))
			{
				msg="请填写您的用户名称！";
				JOptionPane.showMessageDialog(null,msg);
				System.out.println(msg);
			}
			else if(pass.equals(""))
			{
			    msg="请填写您的用户密码！";
			    JOptionPane.showMessageDialog(null,msg);
			    System.out.println(msg);
			}
			else
			try
			{
				Connect conn=new Connect();
				Statement stmt=conn.con.createStatement();
				query="select * from Login where Name='" + name + "'and Psw='" + pass+"'";
				ResultSet rs=stmt.executeQuery(query);
				int result=0;
				while(rs.next())
					result+=1;
				if(result==0)
				{
					msg="你输入了错误的用户名或密码，请检查！";
				JOptionPane.showMessageDialog(null,msg);
				}
				else
				{
					try{
			        msg="欢迎"+name+"登录！";
					JOptionPane.showMessageDialog(null,msg);
					System.out.println("欢迎登录");	
					this.setVisible(false);
					Query qy=new Query();
    				qy.Display();	
    				}catch(Exception g)
    				{
    					msg="查询过程错误！！";
						JOptionPane.showMessageDialog(null,msg);
						System.out.println(msg);	
    				}

				}
			}
			catch(SQLException se)
			{
				String mm;
	       		mm="数据库执行错误："+se.getMessage();
	       		JOptionPane.showMessageDialog(null,mm);
			}
			
		}	
		if(e.getSource()==cancel)
		{
			user.setText("");
			pwd.setText("");
		}
	}

/*public static void main(String args[]) throws Exception
	{
		Login Userpwd=new Login();
		Userpwd.addWindowListener(new MyWindowListener());
		Userpwd.setBounds(400,360,220,130);
	}
*/
}