命令链接在带有 URL 查询字符串的页面内不起作用

Question

我在一个页面中有一个使用带有查询字符串的输出链接进行重定向的页面，例如，

   http://localhost:8070/ChennaiVolunteer/faces/gallery.xhtml?usrId=22

在 gallery.xhtml 中，我有一个命令链接

  <p:commandLink value="List of Activities" action="#{listingActivityData.listofactivities}"  ajax="false">
                    </p:commandLink>

我都在 QueryString“usrId”的 getter 中调用了一个函数

而且每当我单击时 commandLink 我遇到了如下异常：

SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/ChennaiVolunteer] threw exception [java.lang.IllegalArgumentException] with root cause
   java.lang.IllegalArgumentException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at javax.el.BeanELResolver.setValue(BeanELResolver.java:135)
at javax.el.CompositeELResolver.setValue(CompositeELResolver.java:83)
at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.setValue(FacesCompositeELResolver.java:182)
at org.apache.myfaces.config.ManagedBeanBuilder.initializeProperties(ManagedBeanBuilder.java:349)
at org.apache.myfaces.config.ManagedBeanBuilder.buildManagedBean(ManagedBeanBuilder.java:169)
at org.apache.myfaces.el.unified.resolver.ManagedBeanResolver.createManagedBean(ManagedBeanResolver.java:303)
at org.apache.myfaces.el.unified.resolver.ManagedBeanResolver.getValue(ManagedBeanResolver.java:266)
at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:67)
at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:142)
at org.apache.myfaces.el.VariableResolverImpl.resolveVariable(VariableResolverImpl.java:65)
at org.apache.myfaces.el.convert.VariableResolverToELResolver.getValue(VariableResolverToELResolver.java:96)
at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:67)
at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:142)
at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:71)
at org.apache.el.parser.AstValue.getValue(AstValue.java:147)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
at org.apache.myfaces.view.facelets.el.TagValueExpression.getValue(TagValueExpression.java:85)
at javax.faces.component._DeltaStateHelper.eval(_DeltaStateHelper.java:243)
at javax.faces.component.UIData.getValue(UIData.java:1153)
at javax.faces.component.UIData.createDataModel(UIData.java:1101)
at javax.faces.component.UIData.getDataModel(UIData.java:1078)
at javax.faces.component.UIData.setRowIndex(UIData.java:514)
at javax.faces.component.UIData.visitTree(UIData.java:1342)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:770)
at javax.faces.component.UIComponentBase.visitTree(UIComponentBase.java:991)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:770)
at javax.faces.component.UIComponentBase.visitTree(UIComponentBase.java:991)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:770)
at javax.faces.component.UIComponentBase.visitTree(UIComponentBase.java:991)
at org.apache.myfaces.lifecycle.DefaultRestoreViewSupport.processComponentBinding(DefaultRestoreViewSupport.java:84)
at org.apache.myfaces.lifecycle.RestoreViewExecutor.execute(RestoreViewExecutor.java:142)
at org.apache.myfaces.lifecycle.LifecycleImpl.executePhase(LifecycleImpl.java:171)
at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:189)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:964)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:304)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

然后页面重定向到相同的 Outputlink 而没有查询字符串 http://localhost:8070/ChennaiVolunteer/faces/gallery.xhtml

Answer 1

我不确定您到底为什么会遇到此异常，并且不显示 SSCCE 也没有帮助，但根据您使用 MyFaces 的堆栈跟踪，并且您在 并且在创建与表的值关联的托管 bean 时发生异常。该 bean 似乎是请求范围的并且设置托管属性失败。

堆栈跟踪中应该有另一个根本原因，它详细告诉您在设置托管 bean 属性时到底失败的原因。

根据具体的功能需求以及到目前为止您设计页面的方式，我可以想到 2 个解决方案：

1. 将 bean 放入视图范围而不是请求范围中。这样，每次与同一视图交互时，bean 就不会被丢弃并重新创建。只要您与同一视图交互，它就会存在。

   <前><代码>@ManagedBean
   @ViewScoped
   公共类 ListingActivityData {
   // ...
   }

2. 通过将请求参数传递给后续请求。

   ;