jstl 글자 자르기(jstl substring char)

<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>