java - 无法通过 primefaces 命令按钮调用方法

Question

每当我将方法绑定(bind)到 primefaces commandButton 时，该方法显然被识别为属性，并且将抛出 propertyNotFoundException。

我的猜测是，这可能是由于未被识别并因此被翻译成纯 html，这导致该方法被读取为属性。如果是这种情况，我一直无法找到解决方案。

注意:通过 primefaces commandButton 简单地转发到一个页面当然是完美的。

xhtml code extract
<h:form>
<p:commandButton action="#{sessionBean.logout}" value="logout" update="loginForm" ajax="false"></p:commandButton>
</h:form>

支持 bean:

@ManagedBean
@SessionScoped
public class SessionBean implements Serializable {

/**
 * 
 */
private static final long serialVersionUID = 1L;

@SuppressWarnings("unused")
private Object sessionUser;

public SessionBean() {

}

public String logout() {
    FacesContext.getCurrentInstance().getExternalContext().invalidateSession();
    return "login.xhtml?faces-redirect=true";
}

public void setSessionUser(Object user) {
   HttpSession session = (HttpSession)FacesContext.getCurrentInstance().getExternalContext().getSession(true);
   session.setAttribute("sessionUser", user);
}

public Object getSessionUser() {
   HttpSession session = (HttpSession)FacesContext.getCurrentInstance().getExternalContext().getSession(true);
   return session.getAttribute("sessionUser");
}

}

异常(exception):

SEVERE: javax.faces.FacesException: Property 'logout' not found on type mbeans.SessionBean
javax.faces.FacesException: Property 'logout' not found on type mbeans.SessionBean
at com.sun.faces.context.ExceptionHandlerImpl.handle(ExceptionHandlerImpl.java:141)
at     javax.faces.context.ExceptionHandlerWrapper.handle(ExceptionHandlerWrapper.java:100)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:119)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
Caused by: javax.el.PropertyNotFoundException: Property 'logout' not found on type mbeans.SessionBean
at javax.el.BeanELResolver$BeanProperties.get(BeanELResolver.java:237)
at javax.el.BeanELResolver$BeanProperties.access$400(BeanELResolver.java:214)
at javax.el.BeanELResolver.property(BeanELResolver.java:325)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:85)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstValue.getValue(AstValue.java:183)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:185)
at com.sun.faces.facelets.el.ELText$ELTextVariable.toString(ELText.java:217)
at com.sun.faces.facelets.el.ELText$ELTextComposite.toString(ELText.java:157)
at com.sun.faces.facelets.compiler.CommentInstruction.write(CommentInstruction.java:77)
at com.sun.faces.facelets.compiler.UIInstructions.encodeBegin(UIInstructions.java:82)
at com.sun.faces.facelets.compiler.UILeaf.encodeAll(UILeaf.java:207)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:889)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1896)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1899)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1899)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:451)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
... 18 more

Jan 06, 2014 11:03:43 PM com.sun.faces.context.ExceptionHandlerImpl log
1100: JSF1073: javax.el.PropertyNotFoundException caught during processing of RENDER_RESPONSE 6 : UIComponent-ClientId=, Message=Property 'logout' not found on type mbeans.SessionBean
Jan 06, 2014 11:03:43 PM com.sun.faces.context.ExceptionHandlerImpl log
1100: Property 'logout' not found on type mbeans.SessionBean
javax.el.PropertyNotFoundException: Property 'logout' not found on type mbeans.SessionBean
at javax.el.BeanELResolver$BeanProperties.get(BeanELResolver.java:237)
at javax.el.BeanELResolver$BeanProperties.access$400(BeanELResolver.java:214)
at javax.el.BeanELResolver.property(BeanELResolver.java:325)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:85)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstValue.getValue(AstValue.java:183)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:185)
at com.sun.faces.facelets.el.ELText$ELTextVariable.toString(ELText.java:217)
at com.sun.faces.facelets.el.ELText$ELTextComposite.toString(ELText.java:157)
at com.sun.faces.facelets.compiler.CommentInstruction.write(CommentInstruction.java:77)
at com.sun.faces.facelets.compiler.UIInstructions.encodeBegin(UIInstructions.java:82)
at com.sun.faces.facelets.compiler.UILeaf.encodeAll(UILeaf.java:207)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:889)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1896)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1899)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1899)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:451)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)

至于我的项目:我正在使用带有 JSF、primefaces 4.0 和 JPA 2.0 的 Maven 项目

Answer 1

当您调用 #{sessionBean.logout} 时，它会在您的 SessionBean 中查找属性 logout。但是在您的实现中，logout 是一种方法而不是属性。因此请记住添加括号 () 以表明它是一个方法而不是一个属性。 将您的代码更改为:

<p:commandButton action="#{sessionBean.logout()}" value="logout" update="loginForm" ajax="false"></p:commandButton>