JDBC问题

package util;

import java.sql.Connection;

import java.sql.DriverManager;

public class DBHelper {

private static final String driver = "com.mysql.jdbc.Driver"; //数据库驱动

//连接数据库的URL地址

private static final String url="jdbc:mysql://localhost:3306/shopping?useUnicode=true&characterEncoding=UTF-8"; 

private static final String username="root";//数据库的用户名

private static final String password="Aa123456";//数据库的密码

private static Connection conn=null;

//静态代码块负责加载驱动

static 

{

try

{

Class.forName(driver);

}

catch(Exception ex)

{

ex.printStackTrace();

}

}

//单例模式返回数据库连接对象

public static Connection getConnection() throws Exception

{

if(conn==null)

{

conn = DriverManager.getConnection(url, username, password);

return conn;

}

return conn;

}

public static void main(String[] args) {

try

{

  Connection conn = DBHelper.getConnection();

  if(conn!=null)

  {

  System.out.println("数据库连接正常！");

  }

  else

  {

  System.out.println("数据库连接异常！");

  }

}

catch(Exception ex)

{

ex.printStackTrace();

}

}

}

为什么我没写密码就报错，视频中都没写密码