在weblogic上运行程序：在上传一个文件时，页面上报下面的错误！但在tomcat下好使！
Error 500--Internal Server Error
From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:
10.5.1 500 Internal Server Error
The server encountered an unexpected condition which prevented it from fulfilling the request.
查看日志发现，程序的日志里没有报任何错误。但在weblogic日志中报了以下错误！
java.lang.NullPointerException
at weblogic.servlet.internal.ServletResponseImpl.sendError(ServletResponseImpl.java:643)
at org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:725)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:485)
at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:395)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
at com.ipi.coop.util.SecuritFilter2.doFilter(SecuritFilter2.java:56)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
at com.ipi.coop.util.SecuritFilter.doFilter(SecuritFilter.java:79)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3496)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(Unknown Source)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2180)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2086)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1406)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:173)
请各位帮帮忙，看一下到底是哪的原因造成的呢？
