命令按钮don'；t使用Ajax和Param-JSF2.0

我试图在我的项目中用

f:ajax

和

f:param

实现一个命令按钮，但没有成功

我有一个名为“纪律Bean”的Bean，它有一个@SessionScoped。在各自的JSF（比如index.xhtml）中，我有一个

p:dataTable

显示了一些规程（这就是英语中“规程”的意思：p）。当我单击一行时，会打开一个模式，向用户显示“编辑”或“删除”规程的选项。所选对象通过dataTable的

selection

属性存储在“StructuralElecionada”中自己看：

<h:form>
    <label for="nome">Nome:</label>
    <h:inputText styleClass="form-control adicionar" id="nome"
            value="#{disciplinaMBean.disciplinaSelecionada.nome}">
    </h:inputText>

        <h:commandButton id="excluir" styleClass="btn btn-md btn-danger pull-left" value="Excluir" > 
        <f:param name="idDisciplina" value="#{disciplinaSelecionada.id}" />
            <f:ajax event="click" listener="#{disciplinaMBean.deletar}" />
    </h:commandButton>
</h:form>

Disciplina deletada: 
Nov 01, 2013 10:26:31 PM com.sun.faces.lifecycle.InvokeApplicationPhase execute
WARNING: /edit.xhtml @31,72 listener="#{disciplinaMBean.deletar}": java.lang.NumberFormatException: For input string: ""
javax.el.ELException: /edit.xhtml @31,72 listener="#{disciplinaMBean.deletar}": java.lang.NumberFormatException: For input string: ""
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:111)
    at com.sun.faces.facelets.tag.jsf.core.AjaxBehaviorListenerImpl.processAjaxBehavior(AjaxHandler.java:447)
    at javax.faces.event.AjaxBehaviorEvent.processListener(AjaxBehaviorEvent.java:113)
    at javax.faces.component.behavior.BehaviorBase.broadcast(BehaviorBase.java:106)
    at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:760)
    at javax.faces.component.UICommand.broadcast(UICommand.java:300)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:791)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1256)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:395)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:250)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:724)
Caused by: java.lang.NumberFormatException: For input string: ""
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:592)
    at java.lang.Integer.parseInt(Integer.java:615)
    at mbeans.DisciplinaMBean.deletar(DisciplinaMBean.java:143)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:491)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:262)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:278)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
    ... 27 more

此模式的代码位于“edit.xhtml”文件中请参阅下面的代码：

<h:form>
    <label for="nome">Nome:</label>
    <h:inputText styleClass="form-control adicionar" id="nome"
            value="#{disciplinaMBean.disciplinaSelecionada.nome}">
    </h:inputText>

        <h:commandButton id="excluir" styleClass="btn btn-md btn-danger pull-left" value="Excluir" > 
        <f:param name="idDisciplina" value="#{disciplinaSelecionada.id}" />
            <f:ajax event="click" listener="#{disciplinaMBean.deletar}" />
    </h:commandButton>
</h:form>

Disciplina deletada: 
Nov 01, 2013 10:26:31 PM com.sun.faces.lifecycle.InvokeApplicationPhase execute
WARNING: /edit.xhtml @31,72 listener="#{disciplinaMBean.deletar}": java.lang.NumberFormatException: For input string: ""
javax.el.ELException: /edit.xhtml @31,72 listener="#{disciplinaMBean.deletar}": java.lang.NumberFormatException: For input string: ""
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:111)
    at com.sun.faces.facelets.tag.jsf.core.AjaxBehaviorListenerImpl.processAjaxBehavior(AjaxHandler.java:447)
    at javax.faces.event.AjaxBehaviorEvent.processListener(AjaxBehaviorEvent.java:113)
    at javax.faces.component.behavior.BehaviorBase.broadcast(BehaviorBase.java:106)
    at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:760)
    at javax.faces.component.UICommand.broadcast(UICommand.java:300)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:791)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1256)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:395)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:250)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:724)
Caused by: java.lang.NumberFormatException: For input string: ""
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:592)
    at java.lang.Integer.parseInt(Integer.java:615)
    at mbeans.DisciplinaMBean.deletar(DisciplinaMBean.java:143)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:491)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:262)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:278)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
    ... 27 more

我知道我调用该方法是因为控制台的日志，但我无法删除该规程，因为我有一个错误（在“idstricta”参数中存储了一个空字符串）

---

以下是错误：

<h:form>
    <label for="nome">Nome:</label>
    <h:inputText styleClass="form-control adicionar" id="nome"
            value="#{disciplinaMBean.disciplinaSelecionada.nome}">
    </h:inputText>

        <h:commandButton id="excluir" styleClass="btn btn-md btn-danger pull-left" value="Excluir" > 
        <f:param name="idDisciplina" value="#{disciplinaSelecionada.id}" />
            <f:ajax event="click" listener="#{disciplinaMBean.deletar}" />
    </h:commandButton>
</h:form>

Disciplina deletada: 
Nov 01, 2013 10:26:31 PM com.sun.faces.lifecycle.InvokeApplicationPhase execute
WARNING: /edit.xhtml @31,72 listener="#{disciplinaMBean.deletar}": java.lang.NumberFormatException: For input string: ""
javax.el.ELException: /edit.xhtml @31,72 listener="#{disciplinaMBean.deletar}": java.lang.NumberFormatException: For input string: ""
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:111)
    at com.sun.faces.facelets.tag.jsf.core.AjaxBehaviorListenerImpl.processAjaxBehavior(AjaxHandler.java:447)
    at javax.faces.event.AjaxBehaviorEvent.processListener(AjaxBehaviorEvent.java:113)
    at javax.faces.component.behavior.BehaviorBase.broadcast(BehaviorBase.java:106)
    at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:760)
    at javax.faces.component.UICommand.broadcast(UICommand.java:300)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:791)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1256)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:395)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:250)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:724)
Caused by: java.lang.NumberFormatException: For input string: ""
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:592)
    at java.lang.Integer.parseInt(Integer.java:615)
    at mbeans.DisciplinaMBean.deletar(DisciplinaMBean.java:143)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:491)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:262)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:278)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
    ... 27 more

---

我能做些什么来解决这个问题呢？

如果你有EL 2.2，你可以这样做（假设

stricaleselecionada.id

是

int

）

---

谢谢，但是，对不起……什么是EL2.2？我的老师告诉我JSF不能接收参数，必须返回字符串，他不对吗？@FernandoPaladini我能问一下你使用的是哪个操作系统吗？我喜欢that@Fernando：使用EL2.2（表达式语言，这些东西：

{…}

）可以传递参数。是的，如果您想保持当前视图，可以返回void。要执行导航规则，可以返回字符串。您使用的是JSF的哪个版本/实现？如果您使用的是JSF2，那么很可能您使用的是EL2.2。@mohsin:这是Ubuntu。