Iterating through JSONArray in JSP using JSTL

Question

I am sending a list of custom objects with model, and a JSP as a view. My custom object has a property called properties and it is JSONObject. This property will have the value as

{"services":[{"name":"abcd"},{"name":"efgh"}]}

now I want to iterate through the JSONArray [{"name":"abcd"},{"name":"efgh"}]. Here is what I am doing to loop through

<c:if test="${not empty customObject.services}">
                 <c:forEach items="${customObject.services.getJSONArray(\"services\")}" var="Service" varStatus="rowCounterCh">
                     <li>${Service.name}</li>
                  </c:forEach>
 </c:if>

But this is not able to iterate through the JSONArray. Am getting following error.

javax.servlet.ServletException: javax.servlet.jsp.JspTagException: Don't know how to iterate over supplied "items" in &lt;forEach&gt;

So, what should I do to iterate through the JSONArray? Pls help

Exists a lot JSON library in Java. Wich do you use? What package is for joy JSONArray class? — Taky, Jan 22 '13 at 09:57

score 9 · Answer 1 · edited Jan 16 '16 at 15:38

9

I have something like this

<c:forEach begin="0" end="${jsonArray.length() -1}" var="index">
     ${jsonArray.getJSONObject(index).getString("name")}
</c:forEach>

replace ${jsonArray.length() -1} with your jsonArray. In this case, it is something like this

${customObject.services.getJSONArray(\"services\").length()}

edited Jan 16 '16 at 15:38

Tunaki

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answered Jan 16 '16 at 15:37

skuarch

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score 2 · Accepted Answer · edited May 23 '17 at 12:17

2

For each tag should require a base interface for your items. JSONArray neither java.util.Collection nor java.util.Iterable. So For each tag implementation cannot iterate over the collection you pass into items attribute.

To solve this problem you may:

Generate HTML list view with JSP.
Or list item convert JSONArray into some appropriate Collection in customObject.services.getJSONArray method. JSONArray in gson implementation should has method: iterator, because it implements the Iterable interface. Try to return an com.google.gson.JSONArray#iterator() instead of JSONArray in your #getJSONArray(String) method.

more detailed explanation

edited May 23 '17 at 12:17

Community

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answered Jan 22 '13 at 09:52

Taky

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I thought of getting the JSONarray and work upon that inside scriptlet, as `var itemStr ='';` but this is giving me the json array as [{"name":"abcd"},{"name":"efgh"}] which is all the "s are replaced with " how can I avoid this? – Seeker Jan 22 '13 at 11:54
1

Try to set escapeXml attribute to false: http://www.tutorialspoint.com/jsp/jstl_core_out_tag.htm – Taky Jan 22 '13 at 12:33

Iterating through JSONArray in JSP using JSTL

2 Answers2