java制作登陆界面验证问题mysql为数据库：操作报错

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class ConnectionDemo02{
               //public ConnectionDemo02 conn;
	public static final String DBDRIVER="org.gjt.mm.mysql.Driver";
	public static final String DBURL="jdbc:mysql://localhost:3306/wxf";
	public static final String DBUSER="root";
	public static final String DBPASS="26533621";
	public  Connection getConn(){
		Connection conn=null;
		try{
			Class.forName(DBDRIVER);
		}catch (ClassNotFoundException e){
			e.printStackTrace();
		}
		try{
			conn=DriverManager.getConnection(DBURL,DBUSER,DBPASS);
		}catch(SQLException e){
			e.printStackTrace();
		}
		
		return conn;
	}
}

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class Login {
	PreparedStatement ps = null;
	ResultSet rs = null;
	Connection conn = null;

	public boolean verify(String name,String password ) {
		boolean result=false;
		
		String sql = "select * from usekey where idcard=? and password=?";
		Connection con = new ConnectionDemo02().getConn();
		try {
			ps = con.prepareStatement(sql);
			ps.setString(1, name);
			ps.setString(2, password);
			rs = ps.executeQuery();
			
			if (rs.next()) {//验证成功
				result=true;
			}

		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			try {
				if (rs != null)
					rs.close();
				if (ps != null)
					ps.close();
				if (conn != null)
					conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		
		return result;
	}

}

import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import javax.swing.*;
import java.awt.geom.*;
import java.util.Vector;

public class denglu extends JFrame {
	public Label name = new Label("用户名");
	public Label pass = new Label("密码");
	public TextField txtname = new TextField();
	public TextField txtpass = new TextField();
	public Button btok = new Button("登陆");
	public Button btexit = new Button("取消");

	public denglu() {
		setTitle("欢迎使用工资管理系统");
		setLayout(null);

		setResizable(false);
		setSize(500, 350);

		Dimension scr = Toolkit.getDefaultToolkit().getScreenSize();
		Dimension frm = this.getSize();
		setLocation((scr.width - frm.width) / 2,
				(scr.height - frm.height) / 2 - 18);
		txtpass.setEchoChar('*');
		name.setBounds(70, 260, 40, 27);
		pass.setBounds(70, 300, 40, 27);
		txtname.setBounds(120, 260, 120, 27);
		txtpass.setBounds(120, 300, 120, 27);
		btok.setBounds(340, 260, 100, 28);
		btexit.setBounds(340, 300, 100, 28);
		add(name);
		add(txtname);
		add(pass);
		add(txtpass);
		add(btok);
		add(btexit);
		setVisible(true);
		btok.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent arg0) {
				if (验证用户名和密码通过) {
					denglu.this.dispose();
					new yonghu().init();
				}
			}
		});
	}

	public static void main(String args[]) {
		denglu dl = new denglu();
	}
}

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

public class yonghu {
	public void init() {
		JFrame jf = new JFrame();
		jf.setTitle("aaa");
		jf.setBounds(300, 250, 300, 200);
		jf.setVisible(true);
	}
}