how to access an element of arraylist in jsp when index is a variable?

Question

i m accessing an element in an arraylist. the problem arises as the index of the required element is a variable. can anyone plz help me?

eg <td><c:out value="${PARENT_MODULE[module.moduleId]}"> </c:out></td>

here module.moduleId is a variable.

i have already tried

<c:out value="${PARENT_MODULE[${module.moduleId}]}">

however this gives an error.

org.apache.jasper.JasperException: /WEB-INF/jsp/showModules.jsp(40,20) "${PARENT_MODULE[${module.moduleId}]}" contains invalid expression(s): javax.el.ELException: Error Parsing: ${PARENT_MODULE[${module.moduleId}]}

thanks

You don't need to use ${} around module.moduleId, <c:out value="${PARENT_MODULE[module.moduleId]}"> should work. — obourgain
– obourgain, Commented Feb 27, 2013 at 9:11
thank you so much! i never tried that.. as i thought that was highly unlikely.. — Shubham
– Shubham, Commented Feb 27, 2013 at 9:26

obourgain · Accepted Answer · 2013-02-27 10:09:52Z

6

As module.moduleId is inside an EL expression, it will be evaluated. So you don't need to enclose it in an additional ${}.

<c:out value="${PARENT_MODULE[module.moduleId]}"> will work.

answered Feb 27, 2013 at 10:09

obourgain

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Bernie · Accepted Answer · 2013-03-03 02:33:21Z

2

Assuming PARENT_MODULE is the alias you gave the array of modules Assuming module is the object and moduleId is an attribute in the module object

try this:

< c:out value="${PARENT_MODULE[num].moduleId}"/>

where num is a number. PARENT_MODULE[num] would return the object module at the "num" position in the array. and after that all you have to do is access the moduleId attribute.

edited Mar 3, 2013 at 2:33

Bernie

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answered Mar 3, 2013 at 1:58

Shardayyy

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