javax.faces.FacesException: Exception while calling encodeEnd on component

javax.faces.FacesException: Exception while calling encodeEnd on component : {Component-Path : [Class: org.ajax4jsf.component.AjaxViewRoot,ViewId: /member/investmentForm.xhtml][Class: javax.faces.component.html.HtmlForm,Id: j_id75][Class: javax.faces.component.html.HtmlInputHidden,Id: itemId]}
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:559)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:250)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:246)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:246)
at com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.java:592)
at org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:108)
at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:196)
at org.apache.myfaces.lifecycle.RenderResponseExecutor.execute(RenderResponseExecutor.java:41)
at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:140)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:152)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:177)
at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:267)
at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:380)
at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:507)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:164)
at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:141)
at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:90)
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:406)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.leadton.pmjj.webapp.filter.LocaleFilter.doFilterInternal(LocaleFilter.java:76)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:359)
at org.springframework.security.intercept.web.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
at org.springframework.security.intercept.web.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:371)
at org.springframework.security.ui.SessionFixationProtectionFilter.doFilterHttp(SessionFixationProtectionFilter.java:67)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:371)
at org.springframework.security.ui.ExceptionTranslationFilter.doFilterHttp(ExceptionTranslationFilter.java:101)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:371)
at org.springframework.security.providers.anonymous.AnonymousProcessingFilter.doFilterHttp(AnonymousProcessingFilter.java:105)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:371)
at org.springframework.security.wrapper.SecurityContextHolderAwareRequestFilter.doFilterHttp(SecurityContextHolderAwareRequestFilter.java:91)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:371)
at org.springframework.security.ui.AbstractProcessingFilter.doFilterHttp(AbstractProcessingFilter.java:271)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:371)
at org.springframework.security.context.HttpSessionContextIntegrationFilter.doFilterHttp(HttpSessionContextIntegrationFilter.java:235)
at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:371)
at org.springframework.security.util.FilterChainProxy.doFilter(FilterChainProxy.java:174)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:236)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.leadton.pmjj.webapp.filter.RequestFromFilter.doFilter(RequestFromFilter.java:47)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:96)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
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.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
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:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
Caused by: javax.faces.FacesException: Could not retrieve value of component with path : {Component-Path : [Class: org.ajax4jsf.component.AjaxViewRoot,ViewId: /member/investmentForm.xhtml][Class: javax.faces.component.html.HtmlForm,Id: j_id75][Class: javax.faces.component.html.HtmlInputHidden,Id: itemId]}
at org.apache.myfaces.shared_impl.renderkit.RendererUtils.getValue(RendererUtils.java:331)
at org.apache.myfaces.shared_impl.renderkit.RendererUtils.getStringValue(RendererUtils.java:275)
at org.apache.myfaces.renderkit.html.HtmlHiddenRenderer.encodeEnd(HtmlHiddenRenderer.java:55)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:556)
... 72 more
Caused by: javax.el.ELException: /member/investmentForm.xhtml @25,82 value="#{investmentInfoForm.investmentInfo.id}": Error reading 'investmentInfo' on type com.leadton.pmjj.webapp.action.InvestmentInfoForm
at com.sun.facelets.el.TagValueExpression.getValue(TagValueExpression.java:76)
at javax.faces.component.UIOutput.getValue(UIOutput.java:68)
at org.apache.myfaces.shared_impl.renderkit.RendererUtils.getValue(RendererUtils.java:327)
... 75 more
Caused by: java.lang.NullPointerException
at com.leadton.pmjj.webapp.action.InvestmentInfoForm.getInvestmentInfo(InvestmentInfoForm.java:100)
at sun.reflect.GeneratedMethodAccessor186.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:62)
at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:53)
at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.access$301(FacesCompositeELResolver.java:46)
at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver$4.invoke(FacesCompositeELResolver.java:108)
at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.invoke(FacesCompositeELResolver.java:148)
at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:104)
at org.apache.el.parser.AstValue.getValue(AstValue.java:118)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
at com.sun.facelets.el.TagValueExpression.getValue(TagValueExpression.java:71)
... 77 more
我也就加了一个<h:inputHidden id="itemId" value="#{investmentInfoForm.investmentInfo.id}"/>然后就报错了，这个是怎么回事！