jsp配置mysql问题。急啊，谢谢！！！

用tomcat和mysql 做jsp  是连接是出现异常。如下：
HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:372)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause java.lang.NullPointerException
hospital.db.dboperation.DBOperation.closeConnection(dboperation.java:64)
org.apache.jsp.patient.register_jsp._jspService(register_jsp.java:114)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.
--------------------------------------------------------------------------------Apache Tomcat/5.0.28
查看日志文件说：
2005-05-18 11:06:17 org.gjt.mm.mysql.MysqlIO.init() Ln 370:   Communication link failure: java.io.EOFException
是不是驱动有问题啊。怎么改啊！我用的驱动是在lib下放的.jar环境变量还用不 用添加啊！！怎么添加