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jsonjspjstlel

How to compare to net.sf.json.JSONObject.NULL constant in EL expression

I'm using net.sf.json.JSONObject. A null value in the JSON object is not equivalent to Java null. The statement, <c:if test='${not empty obj.value}'> is not working. Is there any way to compare JSON null in the JSTL tag?

Solution

  • If you're already on EL 3.0+, then you can do it as follows:

    <%@ page import="net.sf.json.JSONObject" %>
...
<c:if test="${JSONObject.NULL eq obj.value}">

    If you're not on EL 3.0 yet and thus cannot import constants into EL scope as given above, then use the work around given below which basically checks the Class#getSimpleName():

    <c:if test="${obj.value['class'].simpleName eq 'JSONNull'}">