我正在开始使用JSF Flow。我正在按照本教程http://courses.coreservlets.com/Course-Materials/pdf/jsf/jsf2/JSF-2.2-Faces-Flow-1.pdf第6-12页中的说明进行操作。

隐式导航对我不起作用，就像教程中一样。当我导航到index. xhtml，然后单击命令按钮到sampleFlow时，我得到了nullPointerException。点击刷新/F5后，我的流页被加载。然后我可以使用Page-A和Page-B链接。但是每当我想导航出流时，使用index，sampleFlow-back，我都会得到相同的堆栈。

玻璃鱼原木

FATAL:   JSF1073: javax.faces.FacesException caught during processing of INVOKE_APPLICATION 5 : UIComponent-ClientId=, Message=null
FATAL:   No associated message
javax.faces.FacesException
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:89)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
    at com.sun.faces.flow.FlowCDIContext.flowEntered(FlowCDIContext.java:423)
    at com.sun.faces.flow.FlowHandlerImpl.pushFlow(FlowHandlerImpl.java:392)
    at com.sun.faces.flow.FlowHandlerImpl.transition(FlowHandlerImpl.java:280)
    at com.sun.faces.application.NavigationHandlerImpl.handleNavigation(NavigationHandlerImpl.java:240)
    at com.sun.faces.application.NavigationHandlerImpl.handleNavigation(NavigationHandlerImpl.java:183)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:132)
    at javax.faces.component.UICommand.broadcast(UICommand.java:315)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    ... 31 more

我创建了简单的应用程序，结构如下：

|   index.xhtml
|   sampleFlow-return.xhtml
|
+---sampleFlow
|       page_a.xhtml
|       page_b.xhtml
|       sampleFlow-flow.xml
|       sampleFlow.xhtml
|
\---WEB-INF
        web.xml

每个*. xhtml页面都包含相同的命令集按钮

<h:form>
    <h:commandButton action="sampleFlow" value="sampleFlow"/><br/>
    <h:commandButton action="page_a" value="sampleFlow - page A"/><br/>
    <h:commandButton action="page_b" value="sampleFlow - page B"/><br/>
    <h:commandButton action="sampleFlow-return" value="sampleFlow - return"/><br/>
    <h:commandButton action="index" value="Home"/><br/>
</h:form>

我的sampleFlow-flow. xml是空的，如教程所述。

我正在运行Netbean 8.1和Glassfish 4.1.1