eclipse连接MySQL报错如何解决

<%@ page language="java" import="java.sql.*" pageEncoding="UTF-8"%>
<% request.setCharacterEncoding("UTF-8"); %>
<html>
<head></head>
<body>
<%
  String driverName = "com.mysql.jdbc.Driver";         //驱动程序名
   String userName = "root";                          //数据库用户名
   String userPwd = "123456";                        //密码
   String dbName = "students";                        //数据库名
   String  url1="jdbc:mysql://localhost:3306/"+dbName;
   String url2 ="?user="+userName+"&password="+userPwd;
   String  url3="&useUnicode=true&characterEncoding=UTF-8";
   String url =url1+url2+url3;              
   Class.forName(driverName);                  //加载并注册驱动程序
   Connection conn=DriverManager.getConnection(url); //创建连接对象
%>
</body>
</html>


连接的jar包也导入了,运行出来一开始是connection一行有问题,显示Communications link failure,后来再运行就变成了404The requested resource is not available.
求解答!!

你数据库是什么版本的,驱动包又是什么版本。