如何在一个 < c: if > 中检查两个或多个条件？

如何在一个 <c:if>中检查两个条件? 我尝试了这个方法，但它提出了一个错误:

<c:if test="${ISAJAX == 0} && ${ISDATE == 0}">

jstl
el

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最佳答案

This look like a duplicate of JSTL conditional check.

The error is having the && outside the expression. Instead use

<c:if test="${ISAJAX == 0 && ISDATE == 0}">

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If you are using JSP 2.0 and above It will come with the EL support: so that you can write in plain english and use and with empty operators to write your test:

<c:if test="${(empty object_1.attribute_A) and (empty object_2.attribute_B)}">

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Recommendation:

when you have more than one condition with and and or is better separate with () to avoid verification problems

<c:if test="${(not validID) and (addressIso == 'US' or addressIso == 'BR')}">

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Just in case somebody needs to check the condition from session.Usage of or

<c:if test="${sessionScope['roleid'] == 1 || sessionScope['roleid'] == 4}">