tomcat7 HTTP Status 500 - java.lang.ClassCastException

问题描述：

HTTP Status 500 - java.lang.ClassCastException: org.apache.jasper.el.ELContextImpl cannot be cast to org.apache.jasper.el.ELContextImpl

type Exception report

messagejava.lang.ClassCastException: org.apache.jasper.el.ELContextImpl cannot be cast to org.apache.jasper.el.ELContextImpl

descriptionThe server encountered an internal error that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: java.lang.ClassCastException: org.apache.jasper.el.ELContextImpl cannot be cast to org.apache.jasper.el.ELContextImpl org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334) javax.servlet.http.HttpServlet.service(HttpServlet.java:727) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

java.lang.ClassCastException: org.apache.jasper.el.ELContextImpl cannot be cast to org.apache.jasper.el.ELContextImpl org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:964) org.apache.jsp.index_jsp._jspService(index_jsp.java:85) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) javax.servlet.http.HttpServlet.service(HttpServlet.java:727) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334) javax.servlet.http.HttpServlet.service(HttpServlet.java:727) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

noteThe full stack trace of the root cause is available in the Apache Tomcat/7.0.53 logs.

Apache Tomcat/7.0.53

可以发布项目不报错，访问jsp和http://localhost:8080却是出错了，查了下，说是EL表达式错误，

解决的方案：

修改tomcat的conf文件夹下的context.xml文件

在context元素下添加如下语句<Loader delegate="true" />

具体如下：

<?xml version='1.0' encoding='utf-8'?>

<!--

Licensed to the Apache Software Foundation (ASF) under one or more

contributor license agreements. See the NOTICE file distributed with

this work for additional information regarding copyright ownership.

The ASF licenses this file to You under the Apache License, Version 2.0

(the "License"); you may not use this file except in compliance with

the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software

distributed under the License is distributed on an "AS IS" BASIS,

WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

See the License for the specific language governing permissions and

limitations under the License.

-->

<!-- The contents of this file will be loaded for each web application -->

<Context>

<!-- Default set of monitored resources -->

<WatchedResource>WEB-INF/web.xml</WatchedResource>

<!-- Uncomment this to disable session persistence across Tomcat restarts -->

<!--

<Manager pathname="" />

-->

<Loader delegate="true" /><!-- 添加的东西 -->

<!-- Uncomment this to enable Comet connection tacking (provides events

on session expiration as well as webapp lifecycle) -->

<!--

<Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />

-->

</Context>

修改完后再将tomcat重启即可！