Navigation JSF导航期间的NullPointerException（MyFaces）

在尝试从一个页面导航到另一个页面时，我遇到了NullPointerException。 我已经像往常一样在faces-config.xml中定义了导航规则

但由于某些原因，我的webapp无法导航到下一页。它停留在当前页面上，我得到了看起来像是无限循环的堆栈错误消息

我从Eclipse控制台获得的错误堆栈是：

SEVERE: Servlet.service() for servlet Faces Servlet threw exception
java.lang.NullPointerException
    at javax.faces.component.UIViewRoot.getViewMap(UIViewRoot.java:657)
    at javax.faces.component.UIViewRoot.getViewMap(UIViewRoot.java:645)
    at org.apache.myfaces.renderkit.ErrorPageWriter._writeVariables(ErrorPageWriter.java:574)
    at org.apache.myfaces.renderkit.ErrorPageWriter.debugHtml(ErrorPageWriter.java:288)
    at org.apache.myfaces.renderkit.ErrorPageWriter.debugHtml(ErrorPageWriter.java:250)
    at org.apache.myfaces.renderkit.ErrorPageWriter.handleThrowable(ErrorPageWriter.java:417)
    at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:274)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:191)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:349)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:311)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:101)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:173)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Thread.java:662)

我读过其他论坛的帖子，其中提到了（在web.xml中）：

javax.faces.DEFAULT_后缀
.jsp

我已经这么做了，但是运气不好。 我要强调的是，我以前也参与过其他JSF项目，并顺利实现了页面导航。所以我认为我的导航规则没有问题

我试图导航到的页面称为“login.jsp”。导航规则如下所示：

<navigation-rule>
    <display-name>Global Rule to Login Page</display-name>
    <navigation-case>
        <from-outcome>login</from-outcome>
        <to-view-id>/login.jsf</to-view-id>
    </navigation-case>
</navigation-rule>

登录页面的全局规则
登录
/login.jsf

如有任何意见或建议，我们将不胜感激

非常感谢,，

---

Glen

看起来出现了一些异常，MyFaces准备呈现相应的错误页面。NullPointerException似乎发生在呈现错误页面的过程中。看来原来的错误被隐藏了

您可以尝试禁用MyFaces错误处理，以查看是否找到了根本原因：

<context-param>
  <param-name>org.apache.myfaces.ERROR_HANDLING</param-name>
  <param-value>false</param-value>
</context-param>

org.apache.myfaces.ERROR\u处理
错误的

对不起，我解决了问题，完全忘记更新我的问题。问题是因为我试图从JSF环境之外的页面（index.html）导航到jsp。因此，通过将url重新定向到一个单独的“index.jsf”页面，而不是我将“index.html”的内容移动到的页面，解决了这个问题。上述情况再次发生变化，不再需要重新定向，但这是问题的原因。我希望它能帮助那些遇到同样问题的人。嗨，chkal，谢谢你的建议。在此阶段未为webapp设置错误页面。

<context-param>
  <param-name>org.apache.myfaces.ERROR_HANDLING</param-name>
  <param-value>false</param-value>
</context-param>