消息字符串为空时如何隐藏 div？ （特别是：SPRING_SECURITY_LAST_EXCEPTION.message）

Question

I have a web app built with Bootstrap 3 and Java / Spring MVC.

I'm building a custom login form page for Spring Security.

Works fine except this part where the error message box is always displayed even when the error message is empty string...

<c:if test="${SPRING_SECURITY_LAST_EXCEPTION.message ne ''}">
    <div id="dangerAlert" class="alert alert-danger" >
        ${SPRING_SECURITY_LAST_EXCEPTION.message}
    </div>
</c:if>

How can I check if this string ${SPRING_SECURITY_LAST_EXCEPTION.message} is empty and hide the div?

Answer 1

Answering my own question (and thanks to @Rajeev for pointing me a good direction that helped).

This works...

<c:if test="${not empty SPRING_SECURITY_LAST_EXCEPTION.message}">
    <div id="dangerAlert" class="alert alert-danger" >
        ${SPRING_SECURITY_LAST_EXCEPTION.message}
    </div>
</c:if>

NOTE: Don't forget to import the correct tag lib in your JSP like I did forgot to do...

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>