没有参数的jsf2.0转发页面错误 [英] Jsf2.0 forwarding page error without parameter
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问题描述
你好，我在转发不带参数的页面时出错.那仅在构造函数中发生.方法不会发生.
Hello i have error when i am forwarding page without parameter. that is happen only in constructor. not happening with methods.
喜欢
public EditNewsBean() throws Exception
{
log.info("In EditNewsBean Constructor");
Object o1=request.getParameter("countryCode");
Object o2=request.getParameter("editNewsID");
if(o1==null || o2==null || o1.toString().length()==0 || o2.toString().length()==0)
{
FacesContext.getCurrentInstance().getExternalContext().redirect("/HeWebEV/admin/ManageNews.jsf");
}
setEditNews(Facade.othfac().getTVecNewsFindAllValidTill(request.getParameter("countryCode").toString(),Integer.valueOf(request.getParameter("editNewsID"))));
}
当我传递不带参数的请求表时，出现类似错误
and when i am passing request form without parameter i am getting error like,
com.sun.faces.mgbean.ManagedBeanCreationException: Cant instantiate class: com.efacec.sg.he.plugme.admin.EditNewsBean.
at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:193)
at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:102)
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244)
at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:61)
at org.apache.el.parser.AstValue.getValue(AstValue.java:107)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UIOutput.getValue(UIOutput.java:169)
at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getValue(HtmlBasicInputRenderer.java:205)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getCurrentValue(HtmlBasicRenderer.java:355)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeEnd(HtmlBasicRenderer.java:164)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:312)
at com.sun.faces.renderkit.html_basic.GridRenderer.renderRow(GridRenderer.java:185)
at com.sun.faces.renderkit.html_basic.GridRenderer.encodeChildren(GridRenderer.java:129)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at org.primefaces.renderkit.CoreRenderer.renderChild(CoreRenderer.java:59)
at org.primefaces.renderkit.CoreRenderer.renderChildren(CoreRenderer.java:47)
at org.primefaces.component.panel.PanelRenderer.encodeContent(PanelRenderer.java:185)
at org.primefaces.component.panel.PanelRenderer.encodeMarkup(PanelRenderer.java:108)
at org.primefaces.component.panel.PanelRenderer.encodeEnd(PanelRenderer.java:55)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1763)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1756)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:401)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:410)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
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:235)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.IllegalStateException
at org.apache.catalina.connector.ResponseFacade.sendRedirect(ResponseFacade.java:435)
at com.sun.faces.context.ExternalContextImpl.redirect(ExternalContextImpl.java:576)
at com.efacec.sg.he.plugme.admin.EditNewsBean.<init>(EditNewsBean.java:33)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:188)
... 63 more
15:07:00,342 INFO [context] Exception when handling error trying to reset the response.
com.sun.faces.mgbean.ManagedBeanCreationException: Cant instantiate class: com.efacec.sg.he.plugme.admin.EditNewsBean.
at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:193)
at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:102)
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244)
at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:61)
at org.apache.el.parser.AstValue.getValue(AstValue.java:107)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UIOutput.getValue(UIOutput.java:169)
at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getValue(HtmlBasicInputRenderer.java:205)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getCurrentValue(HtmlBasicRenderer.java:355)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeEnd(HtmlBasicRenderer.java:164)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:312)
at com.sun.faces.renderkit.html_basic.GridRenderer.renderRow(GridRenderer.java:185)
at com.sun.faces.renderkit.html_basic.GridRenderer.encodeChildren(GridRenderer.java:129)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at org.primefaces.renderkit.CoreRenderer.renderChild(CoreRenderer.java:59)
at org.primefaces.renderkit.CoreRenderer.renderChildren(CoreRenderer.java:47)
at org.primefaces.component.panel.PanelRenderer.encodeContent(PanelRenderer.java:185)
at org.primefaces.component.panel.PanelRenderer.encodeMarkup(PanelRenderer.java:108)
at org.primefaces.component.panel.PanelRenderer.encodeEnd(PanelRenderer.java:55)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1763)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1756)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:401)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:410)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
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:235)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.IllegalStateException
at org.apache.catalina.connector.ResponseFacade.sendRedirect(ResponseFacade.java:435)
at com.sun.faces.context.ExternalContextImpl.redirect(ExternalContextImpl.java:576)
at com.efacec.sg.he.plugme.admin.EditNewsBean.<init>(EditNewsBean.java:33)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:188)
... 63 more
15:07:00,366 ERROR [[Faces Servlet]] Servlet.service() for servlet Faces Servlet threw exception
java.lang.IllegalStateException
at org.apache.catalina.connector.ResponseFacade.sendRedirect(ResponseFacade.java:435)
at com.sun.faces.context.ExternalContextImpl.redirect(ExternalContextImpl.java:576)
at com.efacec.sg.he.plugme.admin.EditNewsBean.<init>(EditNewsBean.java:33)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:188)
at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:102)
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244)
at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:61)
at org.apache.el.parser.AstValue.getValue(AstValue.java:107)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UIOutput.getValue(UIOutput.java:169)
at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getValue(HtmlBasicInputRenderer.java:205)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getCurrentValue(HtmlBasicRenderer.java:355)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeEnd(HtmlBasicRenderer.java:164)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:312)
at com.sun.faces.renderkit.html_basic.GridRenderer.renderRow(GridRenderer.java:185)
at com.sun.faces.renderkit.html_basic.GridRenderer.encodeChildren(GridRenderer.java:129)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at org.primefaces.renderkit.CoreRenderer.renderChild(CoreRenderer.java:59)
at org.primefaces.renderkit.CoreRenderer.renderChildren(CoreRenderer.java:47)
at org.primefaces.component.panel.PanelRenderer.encodeContent(PanelRenderer.java:185)
at org.primefaces.component.panel.PanelRenderer.encodeMarkup(PanelRenderer.java:108)
at org.primefaces.component.panel.PanelRenderer.encodeEnd(PanelRenderer.java:55)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1763)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1756)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1759)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:401)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:410)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
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:235)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
15:07:00,405 ERROR [[localhost]] Exception Processing ErrorPage[exceptionType=java.lang.Exception, location=/error.xhtml]
java.lang.IllegalStateException: Cannot reset buffer after response has been committed
at org.apache.catalina.connector.Response.resetBuffer(Response.java:684)
at org.apache.catalina.connector.Response.resetBuffer(Response.java:705)
at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:409)
at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:270)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
推荐答案
com.sun.faces.mgbean.ManagedBeanCreationException: Cant instantiate class: com.efacec.sg.he.plugme.admin.EditNewsBean.
...
java.lang.IllegalStateException: Cannot reset buffer after response has been committed
在视图中，bean显然被相当晚"地引用了.在渲染响应阶段，视图的一部分已经发送(提交)到响应.现在将响应更改为重定向为时已晚.服务器无法从客户端取回已发送的字节.服务器将抛出一个IllegalStateException，而客户端将得到一个半生半熟的响应.
The bean is apparently been referenced pretty "late" in the view. A part of the view is already been sent (committed) to the response during render response phase. It's too late then to change the response into a redirect. The server cannot take the already sent bytes back from the client. The server will throw an IllegalStateException and the client will end up with a halfbaked response.
您需要先执行重定向 ，然后在响应中将任何字节发送到客户端.您可以使用<f:event type="preRenderView">侦听器来实现.将此添加到视图的某个位置(大多数自我记录是将其放在模板客户端的顶部):
You need to perform the redirect before any byte is been sent to the client in the response. You can achieve this with a <f:event type="preRenderView"> listener. Add this somewhere to the view (most self-documenting would be to put this in the top of the template client):
<f:event type="preRenderView" listener="#{editNewsBean.init}" />
并将构造函数的代码移到该方法中.
And move the constructor's code into that method.
public void init() {
// ...
}
无关与具体问题无关，请不要忘记为setEditNews()添加一个else {}块.您不希望在条件符合重定向条件时调用它，对吗?否则，您可能会遇到NullPointerException.另外，完全不需要getParameter()上的toString().另外，您应该通过 <f:viewParam>或@ManagedProperty 或在以下位置收集请求参数至少ExternalContext#getRequestParameterMap().您似乎已将HttpServletRequest分配为Bean的实例变量，这是一个非常糟糕的主意.最后，您将在此处执行重定向，而不是转发.
Unrelated to the concrete problem, don't forget to add an else {} block for setEditNews(). You don't want that it is called when the condition is eligible for the redirect, right? You would otherwise possibly face a NullPointerException. Also, that toString() on getParameter() is completely unnecessary. Also, you should be gathering request parameters by <f:viewParam> or @ManagedProperty or at least ExternalContext#getRequestParameterMap(). You seem to have assigned HttpServletRequest as an instance variable of the bean which is a very bad idea. Finally, you're performing a redirect here, not a forward.
这篇关于没有参数的jsf2.0转发页面错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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