fn:length 문자열 잘라서 길이별로 출력하기

<!-- 제목뿌려주기 -->
<c:choose>
   <c:when test="${fn:length(vo.title) > 20 }">
      <c:out value="${fn:substring(vo.title,0,20) }..." />        
   </c:when>
   <c:otherwise>
      <c:out value="${vo.title}" /> 
   </c:otherwise>
</c:choose>