java.lang.ClassCastException:org.apache.catalina.util.DefaultAnnotationProcessor cannot be cast to o

 在tomcat 中测试comet技术，结果工程出现这样的错误，

 org.apache.jasper.JasperException: java.lang.ClassCastException:org.apache.catalina.util.DefaultAnnotationProcessor cannot be cast to org.apache.AnnotationProcessor

         at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:522)

         at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:356)

 

后来网上查了下，需要

 修改了tomcat里的context.xml文件，在context 元素下添加

 <Loader delegate="true" />

 

 

但是我本地有点问题 ，下面这样子可以，不会报错，

 <Context>

     <Loader delegate="true" />

     <!-- Default set of monitored resources -->
     <WatchedResource>WEB-INF/web.xml</WatchedResource>

     <!-- Uncomment this to disable session persistence across Tomcat restarts -->
     <!--
     <Manager pathname="" />
     -->

     <!-- 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>

 

 

这样子依然会出错

 <Context>

     <!-- Default set of monitored resources -->
     <WatchedResource>WEB-INF/web.xml</WatchedResource>

     <!-- Uncomment this to disable session persistence across Tomcat restarts -->
     <!--
     <Manager pathname="" />
     -->

     <!-- Uncomment this to enable Comet connection tacking (provides events
          on session expiration as well as webapp lifecycle) -->
     <!--
     <Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
     -->

     <Loader delegate="true" />
 </Context>