我正在运行 Fedora 21 发行版中的 Java 和 Tomcat，在最近 Tomcat 7.0.59 更新发布之前，它一直与我的应用程序一起运行良好。现在设置 crossContext="true" 并不能防止抛出致命异常，如果设置了 crossContext="false"，通常会看到这种异常。这是Tomcat版本：
Server version: Apache Tomcat/7.0.59
Server built: Feb 14 2015 21:28:39 UTC
Server number: 7.0.59.0
OS Name: Linux
OS Version: 3.18.9-200.fc21.x86_64
Architecture: amd64
JVM Version: 1.8.0_40-b25
JVM Vendor: Oracle Corporation
这是抛出的异常：
javax.servlet.jsp.JspTagException: Unable to get RequestDispatcher for
Context: "/" and URL:
"/calendar.jsp?nid=0&pid=185&layoutpane_id=7&cid=276&accessuser=".
Verify values and/or enable cross context access.
有任何想法吗？在最近的 Tomcat 版本中似乎有跨上下文请求调度的工作，但我找不到任何专门解决这个问题的东西。这是完整的异常跟踪：
javax.servlet.jsp.JspTagException: Unable to get RequestDispatcher for Context: "/"
and URL: "/calendar.jsp?nid=0&pid=185&layoutpane_id=7&cid=276&accessuser=".
Verify values and/or enable cross context access.
org.apache.taglibs.standard.tag.common.core.ImportSupport.acquireString(ImportSupport.java:278)
org.apache.taglibs.standard.tag.common.core.ImportSupport.doEndTag(ImportSupport.java:161)
org.apache.jsp.index_jsp._jspService(index_jsp.java:3021)
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:395)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:221)
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:190)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)