报异常，是什么异常？如何解决？

Question

Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:535)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:433)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:174)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:78)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)
root cause java.lang.NullPointerException
org.action.UserAction.addJjin(UserAction.java:116)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:270)
org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:187)
org.apache.struts.actions.MappingDispatchAction.execute(MappingDispatchAction.java:169)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:174)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:78)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.20 logs.
--------------------------------------------------------------------------------Apache Tomcat/5.5.20

Answer 1

在UserAction中的存在有空对象。

Answer 2

UserAction的addJjin方法，第116行，有一个空指针异常

Answer 3

查看下116行调用的方法，是不是使用null对象调用了方法

Answer 4

汗。。貌似是SESSION超时导致的。。我是说重启了TOMCAT就可以了

Answer 5

如果是session超时造成的，那楼主要好好看看代码的健壮性了

Answer 6

恩，XML里面设置好了。整了80分钟，看它还超时不

Answer 7

不是这个问题，你得确保你的程序在session超时时还可以跑得通