[求助]请问关于配置jdk+tomcat+mysqlserver

请问高手，我配置半天，jsp是能运行了，就是连接不了数据库mysql server？？？运行测试例子运行不了？？？以下是提示:

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: Access denied for user ''@'localhost' (using password: NO)
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:375)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

javax.servlet.ServletException: Access denied for user ''@'localhost' (using password: NO)
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:858)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:791)
org.apache.jsp.by_jsp._jspService(by_jsp.java:99)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.sql.SQLException: Access denied for user ''@'localhost' (using password: NO)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2921)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:770)
com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:3641)
com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1175)
com.mysql.jdbc.Connection.createNewIO(Connection.java:2544)
com.mysql.jdbc.Connection.<init>(Connection.java:1474)
com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:264)
java.sql.DriverManager.getConnection(Unknown Source)
java.sql.DriverManager.getConnection(Unknown Source)
org.apache.jsp.by_jsp._jspService(by_jsp.java:66)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

note The full stack trace of the root cause is available in the Apache Tomcat/5.5.16 logs.

请问是不是没有配置servlet的问题？？？？如果不是那是什么问题？？？如果是，那该怎么配置？？？？