将 h:commandButton 和 f:param 添加到 h:dataTable 时出现 IllegalArgumentException

Question

目前我正在使用数据表来显示数据库中的一些项目。工作正常。

<h:dataTable border="1" value="#{overviewBean.loadContent }" var="item" first="0" >
    <h:column id="column1">
        <f:facet name="header">
            <h:outputText value="#{messages.overviewSubscriptionID }"></h:outputText>
        </f:facet>
        <h:outputText value="#{item.subscriptionID }"></h:outputText>
    </h:column>
    <h:column id="column2">
        <f:facet name="header">
            <h:outputText value="#{messages.overviewCourseID}"></h:outputText>
        </f:facet>
        <h:outputText value="#{item.courseID }"></h:outputText>
    </h:column>
    ...
    <h:column id="column13">
        <f:facet name="header">
            <h:outputText value="#{messages.overviewDeleteItem }"></h:outputText>
        </f:facet>
        <h:commandButton action="#{overviewBean.delete}" value="X">
            <f:param name="delete" value="#{item.courseID}"></f:param>
        </h:commandButton>
    </h:column>
</h:dataTable>

现在只要有 param-tag 存在，页面就不会加载。这是抛出的异常：

/overview.jsp(15,1) '#{overviewBean.loadContent }' java.lang.IllegalArgumentException
Caused by:
java.lang.IllegalArgumentException - java.lang.IllegalArgumentException

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Edit: Because requested, I added the entire stacktrace (as seen on the generated page):

org.apache.jasper.el.JspELException: /overview.jsp(15,1) '#{overviewBean.loadContent }' java.lang.IllegalArgumentException
        at org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:107)
        at javax.faces.component.UIData.getValue(UIData.java:1142)
        at javax.faces.component.UIData.createDataModel(UIData.java:1082)
        at javax.faces.component.UIData.getDataModel(UIData.java:1056)
        at javax.faces.component.UIData.getRowCount(UIData.java:449)
        at org.apache.myfaces.shared_impl.renderkit.html.HtmlTableRendererBase.encodeInnerHtml(HtmlTableRendererBase.java:234)
        at org.apache.myfaces.shared_impl.renderkit.html.HtmlTableRendererBase.encodeChildren(HtmlTableRendererBase.java:143)
        at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:627)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:250)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:257)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:257)
        at org.apache.myfaces.application.jsp.JspViewHandlerImpl.actuallyRenderView(JspViewHandlerImpl.java:427)
        at org.apache.myfaces.application.jsp.JspViewHandlerImpl.renderView(JspViewHandlerImpl.java:383)
        at org.apache.myfaces.lifecycle.RenderResponseExecutor.execute(RenderResponseExecutor.java:41)
        at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:140)
        at javax.faces.webapp.FacesServlet.service(FacesServlet.java:187)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
        at java.lang.Thread.run(Thread.java:662)
    Caused by: javax.faces.el.EvaluationException: java.lang.IllegalArgumentException
        at org.apache.myfaces.el.VariableResolverImpl.resolveVariable(VariableResolverImpl.java:80)
        at org.apache.myfaces.el.convert.VariableResolverToELResolver.getValue(VariableResolverToELResolver.java:95)
        at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:54)
        at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:142)
        at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:68)
        at org.apache.el.parser.AstValue.getValue(AstValue.java:112)
        at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
        at org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:101)
        ... 27 more
    Caused by: javax.el.ELException: java.lang.IllegalArgumentException
        at javax.el.BeanELResolver.setValue(BeanELResolver.java:116)
        at javax.el.CompositeELResolver.setValue(CompositeELResolver.java:69)
        at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.setValue(FacesCompositeELResolver.java:182)
        at org.apache.myfaces.config.ManagedBeanBuilder.initializeProperties(ManagedBeanBuilder.java:268)
        at org.apache.myfaces.config.ManagedBeanBuilder.buildManagedBean(ManagedBeanBuilder.java:92)
        at org.apache.myfaces.el.unified.resolver.ManagedBeanResolver.createManagedBean(ManagedBeanResolver.java:198)
        at org.apache.myfaces.el.unified.resolver.ManagedBeanResolver.getValue(ManagedBeanResolver.java:164)
        at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:54)
        at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:142)
        at org.apache.myfaces.el.VariableResolverImpl.resolveVariable(VariableResolverImpl.java:65)
        ... 34 more
    Caused by: java.lang.IllegalArgumentException
        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 javax.el.BeanELResolver.setValue(BeanELResolver.java:108)
        ... 43 more

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Edit 2: Here's a link to the page that's actually generated: index_jsp.html

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有什么想法吗？ 该 bean 已注册并且工作正常。删除方法也存在。 （列 ID 也是正确的）

Answer 1

根据堆栈跟踪，您正在使用 MyFaces。这可能是 MyFaces 特有的，我从未在 Mojarra 上见过这个，我已经使用了很多年了。

至少，在 h:commandButton 中使用 f:param 在 JSF 1.x 上是行不通的。它仅适用于 h:commandLink。另一方面，您应该将数据表的值包装在 DataModel 中，以便您可以获得按下按钮的行。或者，如果您使用的是 JSF 1.2，则还可以使用 f:setPropertyActionListener。您可以在此答案中找到示例。