Conditions in JSTL

Posted on 19-02-2013 17:27 by graham
This short tutorial describes how to create conditional code in JSTL.

Including JSTL in your JSP page


The first thing you need to do is to include the JSTL tag library in your JSP page. To do this, place the following directive at the beginning of the JSP file:
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

Conditional structures in JSTL


In JSTL, two conditional structures are available. One is the <c:if ...> tag, the other one is <c:choose ...>.

Using <c:if ...>


Use <c:if ...> if you want to create a simple if ... condition, without any else clause:
<c:if test="${results > 0}">
The search has returned ${results} results.
</c:if>

Using <c:choose ...>


To simulate an if ... else ... condition, use the <c:choose ...> tag:
<c:choose>
<c:when test="${results > 0}">
The search has returned some results
</c:when>

<c:otherwise>
The search hasn't returned any results.
</c:otherwise>
</c:choose>

AND and OR conditions


The test attribute of the <c:if> and <c:choose> tag can contain a single condition, an alternative of conditions or a conjunctions.

For an AND conditions, use:
<c:if test="${age < 20 && sex == 'female'}">
Hey girl!
</c:if>


For an OR conditions, use:
<c:if test="${age < 25 || age > 65}">
You have a discount on bus fares!
</c:if>
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