我正在尝试在后端呈现一些 html 并返回到 js 脚本进行附加。
我的模板：
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:s="http://jboss.com/products/seam/taglib"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
<s:div styleClass="friendActionColumn" rendered="#{not actionDone}">
<h:form styleClass="add">
<h:commandLink id="addAction"
action="#{action.action()}"
value="#{messages['profile.action']}"
rendered="#{action.isAllowed()}"/>
</h:form>
</s:div>
</ui:composition>
我的豆子：
@SuppressWarnings({"unchecked"})
@Name("actionBean")
@Scope(ScopeType.CONVERSATION)
@AutoCreate
public class ActionBean implements Serializable {
@Out(required = false)
private JSONObject uploadResult;
public void action() {
...Some cool code over here
if (this.isAllowedMoreAction(currentPage)) {
Contexts.getEventContext().set("nextPage", currentPage + 1);
}
uploadResult = new JSONObject()
.put("msg", Renderer.instance().render("/myTemplate.xhtml"));
}
}
这适用于常规的 html 和 seam 标签，但是当添加<h:form>, 或任何 h 标签时，我得到一个 Nullpointer 异常。您能否向我解释一下为什么以及如何解决这个问题！
堆栈跟踪：
15:28:09,562 ERROR [Exceptions] handled and logged exception
javax.el.ELException: java.lang.NullPointerException
at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:339)
at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:280)
at org.jboss.el.parser.AstMethodSuffix.getValue(AstMethodSuffix.java:59)
at org.jboss.el.parser.AstMethodSuffix.invoke(AstMethodSuffix.java:65)
at org.jboss.el.parser.AstValue.invoke(AstValue.java:96)
at org.jboss.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276)
at org.jboss.seam.core.Expressions$2.invoke(Expressions.java:175)
at org.jboss.seam.navigation.Page.preRender(Page.java:311)
at org.jboss.seam.navigation.Pages.preRender(Pages.java:351)
at org.jboss.seam.jsf.SeamPhaseListener.preRenderPage(SeamPhaseListener.java:561)
at org.jboss.seam.jsf.SeamPhaseListener.beforeRenderResponse(SeamPhaseListener.java:472)
at org.jboss.seam.jsf.SeamPhaseListener.beforeServletPhase(SeamPhaseListener.java:148)
at org.jboss.seam.jsf.SeamPhaseListener.beforePhase(SeamPhaseListener.java:118)
at com.sun.faces.lifecycle.Phase.handleBeforePhase(Phase.java:214)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:96)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:266)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83)
at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:176)
at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:145)
at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:92)
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:381)
at se.my.web.filter.MyUrlRewriteFilter.doFilter(MyUrlRewriteFilter.java:55)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at se.my.web.filter.SmallCaseFilter.doFilter(SmallCaseFilter.java:67)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:40)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at se.my.web.filter.UserAgentFilter.wrappedCall(UserAgentFilter.java:92)
at se.my.web.filter.UserAgentFilter.doFilter(UserAgentFilter.java:78)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at se.my.web.filter.MDCFilter.doFilter(MDCFilter.java:61)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:60)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:73)
at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:206)
at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:56)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at se.my.web.filter.SaveRequestResponseFilter.doFilter(SaveRequestResponseFilter.java:47)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at se.my.web.filter.DisableUrlSessionFilter.doFilter(DisableUrlSessionFilter.java:89)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
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:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:173)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:182)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:241)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
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:680)
Caused by: java.lang.NullPointerException
at com.sun.facelets.FaceletViewHandler.writeState(FaceletViewHandler.java:776)
at org.ajax4jsf.application.ViewHandlerWrapper.writeState(ViewHandlerWrapper.java:114)
at org.ajax4jsf.application.AjaxViewHandler.writeState(AjaxViewHandler.java:128)
at com.sun.faces.renderkit.html_basic.FormRenderer.encodeEnd(FormRenderer.java:176)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:861)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:937)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:933)
at com.sun.facelets.component.RepeatRenderer.encodeChildren(RepeatRenderer.java:50)
at com.sun.facelets.component.UIRepeat.process(UIRepeat.java:357)
at com.sun.facelets.component.UIRepeat.encodeChildren(UIRepeat.java:617)
at org.jboss.seam.ui.util.JSF.renderChild(JSF.java:175)
at org.jboss.seam.ui.util.JSF.renderChildren(JSF.java:163)
at org.jboss.seam.ui.facelet.RendererRequest.renderFacelet(RendererRequest.java:140)
at org.jboss.seam.ui.facelet.RendererRequest.run(RendererRequest.java:107)
at org.jboss.seam.ui.facelet.FaceletsRenderer.render(FaceletsRenderer.java:43)
at se.my.friends.FriendsBean.loadUserFriendsAjax(FriendsBean.java:118)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.jboss.seam.util.Reflections.invoke(Reflections.java:22)
at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:32)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:77)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:44)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
at se.my.utils.timing.TimingInterceptor.timeCall(TimingInterceptor.java:45)
at sun.reflect.GeneratedMethodAccessor144.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.jboss.seam.util.Reflections.invoke(Reflections.java:22)
at org.jboss.seam.intercept.Interceptor.aroundInvoke(Interceptor.java:187)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:72)
at org.jboss.seam.transaction.RollbackInterceptor.aroundInvoke(RollbackInterceptor.java:28)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
at org.jboss.seam.bpm.BusinessProcessInterceptor.aroundInvoke(BusinessProcessInterceptor.java:51)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
at org.jboss.seam.security.SecurityInterceptor.aroundInvoke(SecurityInterceptor.java:163)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
at org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:185)
at org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:103)
at se.my.friends.FriendsBean_$$_javassist_seam_42.loadUserFriendsAjax(FriendsBean_$$_javassist_seam_42.java)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:335)
... 74 more