spring:eval displays 'null' when expression evaluates to null [SPR-7459]

[spring-projects-issues]

Florian Fankhauser opened SPR-7459 and commented

When the expression in a spring:eval tag evaluates to null, the string 'null' is displayed. I think the right behaviour would be an empty string because that would be consistent with the behaviour of JSP EL and spring:bind.

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Affects: 3.0.3

Referenced from: commits 34ebad5

[spring-projects-issues]

Florian Fankhauser commented

I use this custom tag as workaround:

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
<%@ attribute name="expression" required="true"rtexprvalue="false" %>

<spring:eval expression="${expression}" var="value" />
<c:if test="${value != null}">
<spring:eval expression="${expression}" />
</c:if>

[spring-projects-issues]

Juergen Hoeller commented

Good point - that null rendering was an accident. Fixed for 3.0.4, rendering an empty String in the null case now.

Juergen

[spring-projects-issues]

Keith Donald commented

For reference, this issue was originally reported here:
http://stackoverflow.com/questions/3457134/how-to-display-a-formatted-datetime-in-spring-mvc-3-0