我是Spring的新手，我有一个带有2个方法的simpleFormController。在页面加载时调用referenceData（）with，在提交表单时调用onSubmitAction（）。我的所有onSubmitAction（）代码完成后我得到一个nullPointerExcpetion，我怀疑它与方法完成后控制流的位置有关。我希望在submitAction（）之后调用referenceData（），以便页面的行为与首次加载时的行为方式相同。
我有另一项要求可能改变我的想法。我想根据onSubmitAction（）的结果传回成功或错误消息。做这个的最好方式是什么。以下是我的代码的相关部分：
protected Map referenceData(PortletRequest arg0, Object arg1, Errors arg2) throws Exception
{
Map<String, Object> model = new HashMap<String, Object>();
List<Communication> allCommunications = dao.getAllCommunications();
model.put("allCommunications", allCommunications);
model.put("error", ""); //not sure how to get this data
model.put("success", ""); //not sure how to get this data
return model;
}
protected void onSubmitAction(ActionRequest argRequest,
ActionResponse argResponse, Object command, BindException errors)
throws Exception
{
Communication form = (Communication) command;
dao.updateCommunication(form);
//I want to set a success message here that can be read in the JSP
<bean id="communicationsValidator" class="com.admin.portlet.communication.CommunicationsValidator"/>
<bean id="communicationsController" class="com.admin.portlet.communication.CommunicationsAdminController">
<property name="commandName" value="communications"/>
<property name="commandClass" value="com.admin.portlet.communication.vo.Communication"/>
<property name="formView" value="communications/communicationsAdmin"/>
<property name="successView" value="communications/communicationsAdmin"/>
<property name="validator"><ref bean="communicationsValidator"/></property>
<property name="dao"><ref bean="communicationsDao"/></property>
</bean>
<bean id="portletModeHandlerMapping" class="org.springframework.web.portlet.handler.PortletModeHandlerMapping">
<property name="order" value="1"/>
<property name="portletModeMap">
<map>
<entry key="view"><ref bean="communicationsController"/></entry>
</map>
</property>
</bean>
提前感谢任何建议......
添加了堆栈跟踪
18/11/09 10:08:38:454 GMT] 0000002a ServletWrappe E SRVE0068E: Uncaught exception thrown in one of the service methods of the servlet: /WEB-INF/jsp/communications/communicationsAdmin.jsp. Exception thrown : java.lang.NullPointerException
at com.ibm._jsp._communicationsAdmin._jspService(_communicationsAdmin.java:212)
at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:85)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:989)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:501)
at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:464)
at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:122)
at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:205)
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:639)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:227)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:257)
at org.springframework.web.servlet.ViewRendererServlet.renderView(ViewRendererServlet.java:111)
at org.springframework.web.servlet.ViewRendererServlet.processRequest(ViewRendererServlet.java:84)
at org.springframework.web.servlet.ViewRendererServlet.doGet(ViewRendererServlet.java:65)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:743)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:989)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:501)
at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:464)
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:639)
at org.apache.jetspeed.dispatcher.JetspeedRequestDispatcher.include(JetspeedRequestDispatcher.java:73)
at org.springframework.web.portlet.DispatcherPortlet.doRender(DispatcherPortlet.java:1140)
at org.springframework.web.portlet.DispatcherPortlet.render(DispatcherPortlet.java:1094)
at org.springframework.web.portlet.DispatcherPortlet.doRenderService(DispatcherPortlet.java:832)
at org.springframework.web.portlet.FrameworkPortlet.processRequest(FrameworkPortlet.java:483)
at org.springframework.web.portlet.FrameworkPortlet.doDispatch(FrameworkPortlet.java:453)
at javax.portlet.GenericPortlet.render(GenericPortlet.java:163)
at org.apache.jetspeed.factory.JetspeedPortletInstance.render(JetspeedPortletInstance.java:103)
at org.apache.jetspeed.container.JetspeedContainerServlet.doGet(JetspeedContainerServlet.java:277)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:743)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:989)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:501)
at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:464)
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:639)
at org.apache.jetspeed.container.invoker.ServletPortletInvoker.invoke(ServletPortletInvoker.java:273)
at org.apache.jetspeed.container.invoker.ServletPortletInvoker.render(ServletPortletInvoker.java:140)
at org.apache.pluto.PortletContainerImpl.renderPortlet(PortletContainerImpl.java:119)
at org.apache.jetspeed.container.JetspeedPortletContainerWrapper.renderPortlet(JetspeedPortletContainerWrapper.java:121)
at org.apache.jetspeed.aggregator.impl.RenderingJobImpl.execute(RenderingJobImpl.java:271)
at org.apache.jetspeed.aggregator.impl.PortletRendererImpl.renderNow(PortletRendererImpl.java:228)
at org.apache.jetspeed.aggregator.impl.PageAggregatorImpl.aggregateAndRender(PageAggregatorImpl.java:148)
at org.apache.jetspeed.aggregator.impl.PageAggregatorImpl.aggregateAndRender(PageAggregatorImpl.java:144)
at org.apache.jetspeed.aggregator.impl.PageAggregatorImpl.build(PageAggregatorImpl.java:78)
at org.apache.jetspeed.aggregator.AggregatorValve.invoke(AggregatorValve.java:46)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.aggregator.HeaderAggregatorValve.invoke(HeaderAggregatorValve.java:53)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.decoration.DecorationValve.invoke(DecorationValve.java:144)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.resource.ResourceValveImpl.invoke(ResourceValveImpl.java:130)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.pipeline.valve.impl.ActionValveImpl.invoke(ActionValveImpl.java:207)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.container.ContainerValve.invoke(ContainerValve.java:109)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at com.fmr.fcpf.util.PageHistoryValve.invoke(PageHistoryValve.java:161)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.profiler.impl.ProfilerValveImpl.invoke(ProfilerValveImpl.java:248)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.security.impl.LoginValidationValveImpl.invoke(LoginValidationValveImpl.java:159)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.localization.impl.LocalizationValveImpl.invoke(LocalizationValveImpl.java:170)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.security.impl.AbstractSecurityValve$1.run(AbstractSecurityValve.java:138)
at java.security.AccessController.doPrivileged(AccessController.java:215)
at javax.security.auth.Subject.doAsPrivileged(Subject.java:645)
at org.apache.jetspeed.security.JSSubject.doAsPrivileged(JSSubject.java:179)
at org.apache.jetspeed.security.impl.AbstractSecurityValve.invoke(AbstractSecurityValve.java:132)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.container.url.impl.PortalURLValveImpl.invoke(PortalURLValveImpl.java:67)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.capabilities.impl.CapabilityValveImpl.invoke(CapabilityValveImpl.java:126)
at org.apache.jetspeed.pipeline.JetspeedPipeline$Invocation.invokeNext(JetspeedPipeline.java:167)
at org.apache.jetspeed.pipeline.JetspeedPipeline.invoke(JetspeedPipeline.java:146)
at org.apache.jetspeed.engine.JetspeedEngine.service(JetspeedEngine.java:222)
at org.apache.jetspeed.engine.JetspeedServlet.doGet(JetspeedServlet.java:242)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:743)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:989)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:930)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:145)
at com.fmr.fc.common.authentication.FCLoginFilter.doFilter(FCLoginFilter.java:269)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:190)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:130)
at com.fmr.fc.common.authentication.CommonPortalFilter.doFilter(CommonPortalFilter.java:194)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:190)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:130)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:87)
at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:761)
at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:673)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:498)
at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:464)
at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:3252)
at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:264)
at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:811)
at com.ibm.ws.wswebcontainer.WebContainer.handleRequest(WebContainer.java:1439)
at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:112)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:454)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewInformation(HttpInboundLink.java:383)
at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback.complete(HttpICLReadCallback.java:102)
at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165)
at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)
at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161)
at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:136)
at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:195)
at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:743)
at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:873)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1469)
答案 0 :(得分：0)
java.lang.NullPointerException at com.ibm._jsp._communicationsAdmin._jspService(_communicationsAdmin.java:212)
JSP内部导致的异常很难调试，特别是如果您根本没有在JSP中使用scriptlet。这表明使用的taglibrary中存在错误，或者业务逻辑中存在一个简单的配置/流错误，这会在后期显示此异常。
首先，在appserver的工作目录中找到_communicationsAdmin.java文件并调查第212行以查找潜在的无效指针，并最终将其追溯到潜在的配置/流错误。如果您在调试中遇到困难，也可以在此处粘贴相关的（仅相关的是）行，以便我们可以为您找到。