错误:java.lang.NullPointerException,求指教!
jsp+sql2000+Tomcat 5.0,ie浏览器打开用户登录界面,提示以下错误
HTTP Status 500 -
--------------------------------------------------------------------------------
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
java.lang.NullPointerException
com.bean.LoginBean.login(LoginBean.java:20)
com.servlet.LoginServlet.doGet(LoginServlet.java:41)
com.servlet.LoginServlet.doPost(LoginServlet.java:76)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
我纯菜鸟,请问高手怎么解决啊?