jsf-2 - jsf2.0 无参数转发页面错误

Question

您好，我在转发没有参数的页面时出错。那只发生在构造函数中。不会发生在方法上。

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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"))));
}

当我传递没有参数的请求表单时，我收到了错误，例如，

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)

Answer 1

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 

该 bean 显然在 View 中被引用得很“迟”。在渲染响应阶段， View 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。服务器不能从客户端取回已经发送的字节。服务器将抛出 IllegalStateException客户端最终会得到一个半生不熟的响应。

您需要在响应中将任何字节发送到客户端之前执行重定向。您可以使用 <f:event type="preRenderView"> 来实现这一点。听众。将其添加到 View 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):

<f:event type="preRenderView" listener="#{editNewsBean.init}" />

并将构造函数的代码移动到该方法中。

public void init() {
    // ...
}

无关 对于具体问题，不要忘记添加 else {}阻止 setEditNews() .您不希望在条件符合重定向条件时调用它，对吗？否则你可能会面临 NullPointerException .还有，那个 toString()在 getParameter()完全没有必要。此外，您应该通过 <f:viewParam> or @ManagedProperty 收集请求参数。或至少 ExternalContext#getRequestParameterMap() .你好像分配了 HttpServletRequest作为 bean 的实例变量，这是一个非常糟糕的主意。最后，您在此处执行重定向，而不是转发。