Question

I want to do something like this:

            <c:import url="${myvar.url}">
               <c:forEach items="${myvar.params}" var="param">
                  <c:param name="${param.name}" value="${param.value}"/>
               </c:forEach>
            </c:import>

And I get this error:

Illegal child tag in “c:import” tag: “c:forEach” tag

Apparently, the c:import expects c:param within it and it sees a c:forEach instead.

I get the same problem if I try a jsp:include and jsp:params.

Any help ?

Answer 1

You won’t be able to do it with either c:import or jsp:include.

If this is something you’re going to do more than once, you could write a tag file, such as:

<%@ attribute name="url" required="true" %>
<%@ attribute name="paramMap" required="false" type="java.util.Map"%>
<%@ tag trimDirectiveWhitespaces="true"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

<c:if test="${empty paramMap}">
    <c:import url="${url}"/>
</c:if>
<c:if test="${!empty paramMap}">
    <c:set var="paramString" value=""/>
    <c:forEach var="entry" items="${paramMap}">
        <c:if test="${!empty paramString}">
            <c:set var="paramString">${paramString}&</c:set>
        </c:if>
        <c:set var="paramString">${paramString}<c:out value="${entry.key}"/>=<c:out value="${entry.value}"/></c:set>
    </c:forEach>
    <c:url value="${url}?${paramString}" var="fullUrl"/>
    <c:import url="${fullUrl}"/>
</c:if>

Save that as “importParamMap.tag” in your “WEB-INF/tags” folder. To call it in a page, include the tags directory and treat it as any other tag:

<%@ taglib tagdir="/WEB-INF/tags" prefix="tag" %>
...
<tag:importParamMap url="${myVar.url}" paramMap="${myVar.params}"/>