CODEWITHSUNDEEP
javajspjstlscopescriptlet
Cornish
Cornish

Reputation: 899

I can pass a variable from a JSP scriptlet to JSTL but not from JSTL to a JSP scriptlet without an error

The following code causes an error:

 <c:set var="test" value="test1"/>
 <%
   String resp = "abc";
   resp = resp + test;
   pageContext.setAttribute("resp", resp);
 %>
 <c:out value="${resp}"/>

The error says 

"error a line 4: unknown symbol 'test'".

How do I pass test from the JSTL code to the JSP scriptlet?

Upvotes: 55

Views: 121047

Answers (2)

skaffman
skaffman

Reputation: 403591

Scripts are raw java embedded in the page code, and if you declare variables in your scripts, then they become local variables embedded in the page.

In contrast, JSTL works entirely with scoped attributes, either at page, request or session scope. You need to rework your scriptlet to fish test out as an attribute:

<c:set var="test" value="test1"/>
<%
  String resp = "abc";
  String test = pageContext.getAttribute("test");
  resp = resp + test;
  pageContext.setAttribute("resp", resp);
%>
<c:out value="${resp}"/>

If you look at the docs for <c:set>, you'll see you can specify scope as page, request or session, and it defaults to page.

Better yet, don't use scriptlets at all: they make the baby jesus cry.

Upvotes: 113

BalusC
BalusC

Reputation: 1109685

@skaffman nailed it down. They live each in its own context. However, I wouldn't consider using scriptlets as the solution. You'd like to avoid them. If all you want is to concatenate strings in EL and you discovered that the + operator fails for strings in EL (which is correct), then just do:

<c:out value="abc${test}" />

Or if abc is to obtained from another scoped variable named ${resp}, then do:

<c:out value="${resp}${test}" />

Upvotes: 15

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