JSP-我可以使用< jsp:attribute>在< c:if>内部?例外:“必须使用jsp:body来指定标签主体" [英] JSP - Can I use <jsp:attribute> inside <c:if>? Exception: "Must use jsp:body to specify tag body"

问题描述

我在JSP中包含以下内容:

I have the following inside a JSP:

<c:if test="${true}">
<jsp:attribute name="extraInlineComplianceJavascript">
window.isSummaryComplianceLinkVisible = '${TabList.isSummaryComplianceLinkVisible}';
window.isDetailComplianceLinkVisible = '${TabList.isDetailComplianceLinkVisible}';
window.complianceSummaryReportTag = '${helper.complianceSummaryReportTag}';
window.complianceDetailReportTag = '${helper.complianceReportTag}';
</jsp:attribute>
</c:if>

按原样，我得到以下异常:

As is, I get the following exception:

 Must use jsp:body to specify tag body for <MyTag if jsp:attribute is used.

如果我删除最外面的<c:if>标记，它将起作用.在<c:if>中使用<jsp:attribute>是否存在问题?任何帮助，将不胜感激.谢谢.

If I remove the outermost <c:if> tags, it works. Is there a problem with using <jsp:attribute> inside a <c:if> ? Any help would be appreciated. Thanks.

推荐答案

元素的主体被隐式定义为相应元素的主体.正文也可以使用< jsp:body>显式表示.如果一个或多个< jsp:attribute>元素出现在标签的主体中.检出元素，

The body of an element is defined implicitly as the body of the the respective element. The body can also be represented explicitly using <jsp:body>. This is required if one or more <jsp:attribute> elements appear in the body of the tag. Checkout the references for element, attribute and body.

但这不是真正的问题.问题是< jsp:attribute>不能与条件标签配合使用. < jsp:attribute>正在尝试在其父标签(在您的示例中为< c:if>)上设置属性.

But that is not the real problem. The problem is <jsp:attribute> does not play well with conditional tags. The <jsp:attribute> is trying to set the attribute on its parent tag, which in your example is <c:if>.

您可以使用< c:if>元素内部(如BalusC在他的评论中建议的那样)，但这会导致属性值为空，或者您可以从以下位置进行操作:

You could use <c:if> inside the element (as BalusC suggested in his comment), but that will result in a an attribute with an empty value, or you could go from:

<jsp:element ...>
  <c:if test="${true}">
    <jsp:attribute name="extraInlineComplianceJavascript">
      ....
    </jsp:attribute>
  </c:if>
</jsp:element>

到(更详细):

<c:if test="${true}">
  <jsp:element ...>
    <jsp:attribute name="extraInlineComplianceJavascript">
      ....
    </jsp:attribute>
  </jsp:element>
</c:if>
<c:if test="${false}">
  <jsp:element ...>
     <!-- no attribute for false -->
  </jsp:element>
</c:if>

您也可以使用< c:choose>.当然，它不能与多个属性:D一起很好地工作.

You could also use a <c:choose>. And of course it won't work well with more than one attribute :D.

我个人的建议是丢弃< jsp:attribute>并找到另一种有条件地设置属性的方法.

My personal suggestion would be to throw away the <jsp:attribute> and find another way to conditionally set your attributes.

这篇关于JSP-我可以使用&lt; jsp:attribute&gt;在&lt; c:if&gt;内部?例外:“必须使用jsp:body来指定标签主体"的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！