jstl启动报错的问题解决方案

今天遇到了一个问题，很尴尬。头疼了几个小时，最后还是找到了问题的根源。
如下所示报错。
我发现代码部分没有任何问题，写的也很合理，jar包没有缺失，但是为什么总是会报servlet错误，空指针呢。
我的直觉告诉我，一定是jstl部分出现了问题，具体问题在哪里我也不敢可能。只能大概猜测一下，估计是在jar包的位置。
但是我的jar包引用的jstl-2.0的也没有任何问题。那原因是什么呢。只有一个可能就是jar包冲突。没错
于是，我开始寻找错误jar包的位置最后确认到了juel-impl.jar。网上一查，果然没错juel-impl冲突的结果很多。
1.把tomcat的el.api.jar删掉。                    
2.剪切JBPM下的juel-api.jar，juel-impl.jar,juel-engine.jar到tomcat的lib目录下。                  

3.项目里从新添加一次JBPM架包，并重新部署项目。

严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at javax.el.CompositeELResolver.add(CompositeELResolver.java:49)
at org.apache.jasper.el.JasperELResolver.add(JasperELResolver.java:70)
at org.apache.jasper.el.JasperELResolver.<init>(JasperELResolver.java:58)
at org.apache.jasper.runtime.JspApplicationContextImpl.createELResolver(JspApplicationContextImpl.java:115)
at org.apache.jasper.runtime.JspApplicationContextImpl.createELContext(JspApplicationContextImpl.java:88)
at org.apache.jasper.runtime.PageContextImpl.getELContext(PageContextImpl.java:949)
at org.apache.jsp.WEB_002dINF.views.modules.site.jd.index_jsp._jspx_meth_c_005fset_005f0(index_jsp.java:202)
at org.apache.jsp.WEB_002dINF.views.modules.site.jd.index_jsp._jspService(index_jsp.java:142)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:719)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:465)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:390)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:317)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:264)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1208)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:992)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:939)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.opensymphony.sitemesh.webapp.SiteMeshFilter.obtainContent(SiteMeshFilter.java:129)
at com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:77)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1096)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:674)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
DEBUG: org.springframework.web.servlet.DispatcherServlet - Could not complete request
org.apache.jasper.JasperException: An exception occurred processing JSP page /WEB-INF/views/modules/site/jd/index.jsp at line 9


6: <%@ taglib prefix="fnc" uri="/WEB-INF/tlds/fnc.tld" %>
7: <%@ taglib prefix="tags" tagdir="/WEB-INF/tags" %>
8: <%@ taglib prefix="ebx" uri="/WEB-INF/tlds/ebx.tld" %>
9: <c:set var="site885" value="http://localhost:8080/"/>
10: <c:set var="ctx" value="${site885}${pageContext.request.contextPath}${fns:getFrontPath()}"/>
11: <c:set var="ctxfront" value="${site885}${pageContext.request.contextPath}"/>
12: <c:set var="ctxStatic" value="${site885}${pageContext.request.contextPath}/resources"/>




Stacktrace:
at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:574)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:719)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:465)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:390)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:317)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:264)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1208)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:992)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:939)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.opensymphony.sitemesh.webapp.SiteMeshFilter.obtainContent(SiteMeshFilter.java:129)
at com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:77)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1096)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:674)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at javax.el.CompositeELResolver.add(CompositeELResolver.java:49)
at org.apache.jasper.el.JasperELResolver.add(JasperELResolver.java:70)
at org.apache.jasper.el.JasperELResolver.<init>(JasperELResolver.java:58)
at org.apache.jasper.runtime.JspApplicationContextImpl.createELResolver(JspApplicationContextImpl.java:115)
at org.apache.jasper.runtime.JspApplicationContextImpl.createELContext(JspApplicationContextImpl.java:88)
at org.apache.jasper.runtime.PageContextImpl.getELContext(PageContextImpl.java:949)
at org.apache.jsp.WEB_002dINF.views.modules.site.jd.index_jsp._jspx_meth_c_005fset_005f0(index_jsp.java:202)
at org.apache.jsp.WEB_002dINF.views.modules.site.jd.index_jsp._jspService(index_jsp.java:142)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
... 63 more
三月 20, 2017 8:02:27 下午 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet [appServlet] in context with path [/GHouse] threw exception [An exception occurred processing JSP page /WEB-INF/views/modules/site/jd/index.jsp at line 9


6: <%@ taglib prefix="fnc" uri="/WEB-INF/tlds/fnc.tld" %>
7: <%@ taglib prefix="tags" tagdir="/WEB-INF/tags" %>
8: <%@ taglib prefix="ebx" uri="/WEB-INF/tlds/ebx.tld" %>
9: <c:set var="site885" value="http://localhost:8080/"/>
10: <c:set var="ctx" value="${site885}${pageContext.request.contextPath}${fns:getFrontPath()}"/>
11: <c:set var="ctxfront" value="${site885}${pageContext.request.contextPath}"/>
12: <c:set var="ctxStatic" value="${site885}${pageContext.request.contextPath}/resources"/>




Stacktrace:] with root cause
java.lang.NullPointerException