Question

java做的一个登陆界面（补充说明） 怎么连接上数据库来判断是不是用户 并登陆

package java1;

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

class LoginFrm extends JFrame implements ActionListener// throws Exception
{
JLabel lbl1=new JLabel("用户名");
JLabel lbl2=new JLabel("密码");
JTextField txt=new JTextField(15);
JPasswordField pf=new JPasswordField();
JButton btn1=new JButton("确定");
JButton btn2=new JButton("取消");

public LoginFrm()
{
this.setTitle("登陆");
JPanel jp=(JPanel)this.getContentPane();
jp.setLayout(new GridLayout(3,2,10,10));
jp.add(lbl1);jp.add(txt);
jp.add(lbl2);jp.add(pf);
jp.add(btn1);jp.add(btn2);
btn1.addActionListener(this);
btn2.addActionListener(this);
}

public void actionPerformed(ActionEvent ae)
{
if(ae.getSource()==btn1)
{
try
{
Class.forName("com.aaa.jdbc.Driver");//mysql数据库
Connection con=DriverManager.getConnection("jdbc:mysql://localhost/cyimpression","root","");//数据库名为cyimpression，密码为空
Statement cmd=con.createStatement();
ResultSet rs=cmd.executeQuery("select * from register where username='"+txt.getText()+"' and password2='"+pf.getText()+"'");//表名为register，username和password2是存放用户名和密码的字段名
if(rs.next())
{
JOptionPane.showMessageDialog(null,"登陆成功！");
}
else
JOptionPane.showMessageDialog(null,"用户名或密码错误！");
} catch(Exception ex){}

if(ae.getSource()==btn2)
{
txt.setText("");
pf.setText("");
}
}
}

public static void main(String arg[])
{
JFrame.setDefaultLookAndFeelDecorated(true);
LoginFrm frm=new LoginFrm();
frm.setSize(400,200);
frm.setVisible(true);
}
}

Answer 1

sql语句：select * from 表名 where name = ? and pwd = ?
再判断结果集是否为空就可以了

Answer 2

？你这不行吗？

Answer 3

Class.forName("com.aaa.jdbc.Driver");//mysql数据库
这样不行吧。

Answer 4

已经OK了