mysql与tomcat连接中遇到的问题

我刚开始学JSP，从别人那里弄来个源程序，服务器用的是tomcat6.16，数据库用的是mysql5.0，开始不知道怎样连接，后来从网上查了些资料，用JDBC5.08连接，但是弄了几天就是打不开，浏览器上显示如下，麻烦高手指点一下
HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /corrision/conn/conn.jsp at line 14

11: String dbUrl="jdbc:mysql://localhost:3306/OA?useUnicode=true&characterEncoding=GBK";
12: String dbUser="root";
13: String dbPwd="123456";
14: con=java.sql.DriverManager.getConnection(dbUrl,dbUser,dbPwd);
15: stmt=con.createStatement();
16: %>


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:398)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


root cause

javax.servlet.ServletException: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

下载驱动，然后
Connection con;
Statement sql;
ResultSet rs;

Class.forName("org.gjt.mm.mysql.Driver").newInstance();

con=DriverManager.getConnection("jdbc:mysql://localhost/dbname","username","password");
    sql=con.createStatement();
    rs=sql.executeQuery(" select count(*) from tablename");

500是服务器错误！

上传源码看看！
我也正在学习JSP
刚刚测试成功--JSP和ACCESS连接