jstl 글자수 자르기

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

<c:if test="${fn:length(reply.s_content) > 18}">
    <c:out value="${fn:substring(reply.s_content,0,15)}" />...                    
</c:if>
<c:if test="${fn:length(reply.s_content) <= 18}">
    ${reply.s_content}
 </c:if>