Question

I have a hashmap which is stored in a session. The hashMap is a map of maps.

HashMapStoredInSession ={"290" = {text="abc", response="someText"}, "276"={text="xyz", response="random"}};  

I dont want to use scriptlets. But I am stuck with one scriptlet and cant seem to make it work. Any suggestions where I am going wrong would be great.
The following combination of SCRIPTLET + JSTL works

Scriptlet:

<%     
    Map hMap= (Map)request.getSession().getAttribute("HashMapStoredInSession");   
    pageContext.setAttribute("mapofMaps", hMap);  
%>  

JSTL code:

<c:if test="${param.ID != 'null' && not empty param.ID}">   
    <c:set var="someID" value="${param.ID}" scope="session"/>  
</c:if>  
<c:forEach items="${mapofMaps}" var="outerMap">             
    <c:if test="${outerMap.key == someID}">    // this is the line where exception is thrown when the above scriptlet code is replaced with JSTL below                  
        <c:forEach items="${outerMap.value}" var="innerMap">                    
            <c:if test="${innerMap.key == 'param1'}">  
                <c:set var="response1" value="${innerMap.value}"/>  
            </c:if>  
            <c:if test="${innerMap.key == 'param2'}">  
                <c:set var="response2" value="${innerMap.value}"/>  
            </c:if>              
        </c:forEach>  
    </c:if>  
</c:forEach>  

Now if I try to replace scriptlet code with following( with no change in JSTL code)

<c:set var="mapofMaps" value ='<c:out value ="<%=request.getSession().getAttribute("HashMapStoredInSession")%>"/>'/>  

I get the following error

An error occurred while evaluating custom action attribute "test" with value "${outerMap.key == someID}":   
Unable to find a value for "key" in object of class "java.lang.String" using operator "." (null) 

Answer 1

You can just reference it by ${HashMapStoredInSession}.

<c:forEach items="${HashMapStoredInSession}" var="outerMap">             

Or if you really want to rename the attribute name, do so:

<c:set var="mapofMaps" value="${HashMapStoredInSession}" />  

The key is that EL ${} already lookups for attributes in page, request, session and application scopes. So you don’t need to explicitly use session.getAttribute() by a scriptlet.

See also:

• Our EL wiki page