迭代 h:datatable 中的嵌套 List 属性 [英] Iterate over nested List property inside h:datatable

问题描述

    <h:dataTable value="#{SearchingBeans.list}" var="entry">
        <h:column>
            <f:facet name="header">
                <h:outputLabel>Photo</h:outputLabel>
            </f:facet>
        </h:column>
        <h:column>
            <f:facet name="header">
                <h:outputLabel>Pseudo</h:outputLabel>
            </f:facet>
            <h:outputLabel value="#{entry.pseudo}"></h:outputLabel>
        </h:column>
        <h:column>
            <f:facet name="header">
                <h:outputLabel>Description</h:outputLabel>
            </f:facet>
            <h:outputLabel value="#{entry.description}"></h:outputLabel>
        </h:column>
        <h:column>
            <f:facet name="header">
                <h:outputLabel>Photo</h:outputLabel>
            </f:facet>
            <h:outputLabel value="#{entry.photo[0].path}"></h:outputLabel> <-- this a List
        </h:column>
    </h:dataTable>

我有一个实体成员，他的一个财产是带有 get/set 的列表照片该属性已填充我不知道如何在 jsf 中获取该值，我只想要每个成员的第一张照片，因为他们有 2-3 张照片.那有可能吗??任何其他解决方案将不胜感激.

i got a entities member one of his property is a List photo with get/set that property is populate i don't know how to fetch that value in jsf i want only the first picture for each member since their have 2-3 photos. Its that possible?? any other solution will be appreciate.

推荐答案

只需使用 或 迭代它通常的方式.将多个迭代组件相互嵌套是完全有效的.对于，你只需要确保将嵌套的迭代组件放在中.

Just iterate over it using <ui:repeat> or <h:dataTable> the usual way. It's perfectly valid to nest multiple iterating components in each other. In case of <h:dataTable>, you only need to make sure that you put the nested iterating component inside a <h:column>.

例如

<h:dataTable value="#{bean.entities}" var="entity">
    <h:column>
        #{entity.property}
    </h:column>
    <h:column>
        <ui:repeat value="#{entity.subentities}" var="subentity">
            #{subentity.property}
        </ui:repeat>
    </h:column>
</h:dataTable>

或

<h:dataTable value="#{bean.entities}" var="entity">
    <h:column>
        #{entity.property}
    </h:column>
    <h:column>
        <h:dataTable value="#{entity.subentities}" var="subentity">
            <h:column>
                #{subentity.property}
            </h:column>
        </h:dataTable>
    </h:column>
</h:dataTable>

当您嵌套多个 <ui:repeat> 组件并在其中使用 <f:ajax> 而使用较旧的组件时，您可能只会遇到问题Mojarra 版本.

You'll potentially only run into issues when you nest multiple <ui:repeat> components and use <f:ajax> in it while using an older version of Mojarra.

只有 JSTL 在嵌套在 JSF 迭代组件中时不起作用，原因在此说明 JSF2 Facelets 中的 JSTL ......有意义吗?

Only JSTL <c:forEach> wouldn't work when nested inside a JSF iterating component for the reasons explained here JSTL in JSF2 Facelets... makes sense?

与具体问题无关，请不要滥用进行纯文本展示.它生成一个 HTML 元素，该元素旨在 labelfor 属性的输入元素.但是，您在代码中没有这样做.您应该使用 代替.顺便说一句，我最近在初学者代码中更频繁地看到这一点.一定有一个糟糕的教程或资源以这种方式滥用 而不是 甚至模板文本中的普通 EL.您使用的是哪个教程/资源?然后我可以就这个严重的错误指示联系作者.另请参见 h:outputLabel 的用途及其for"属性

Unrelated to the concrete problem, please don't abuse <h:outputLabel> for pure text presentation. It generates a HTML <label> element which is intented to label an input element by for attribute. However, you're doing that nowhere in the code. You should be using <h:outputText> instead. By the way, I'm lately seeing this more often in code of starters. There must be somewhere a bad tutorial or resource which is abusing the <h:outputLabel> this way instead of <h:outputText> or even plain EL in template text. Which tutorial/resource was you using? Then I can contact the author about this severe misinstruction. See also Purpose of the h:outputLabel and its "for" attribute

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