jstl表达式使用方法

1.jstl.jar  servlet.jar支持

2.jsp引入标签库

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

3.条件判断<c:choose><c:if>

<c:choose>
      <c:when test="${requestScope.typeFlag == 0}">
          <a class="fc-a40" href="<%=Constants.ROOT + Constants.MALL_PARTS_PATH%>">配件商城</a>
      </c:when>
      <c:otherwise>
            <a class="fc-a40" href="<%=Constants.ROOT + Constants.MALL_AFFIX_PATH%>">汽车用品</a>
      </c:otherwise>
</c:choose>

<c:forEach var="pic" items="${dto.pics}"  varStatus="st">
        <c:if test="${st.index <= 3}">  
        <li class="hover">
        <a href='javascript:void(0);' rel="{gallery: 'gal1', smallimage: '<%=Constants.ROOT + Constants.PARTSPATH %>${pic.picUrl}',largeimage: '<%=Constants.ROOT + Constants.PARTSPATH %>${pic.picUrl}'}"><img name="clickShowPic" src="<%=Constants.ROOT + Constants.PARTSPATH %>${pic.picUrl}" width="58" height="58" /></a>
        </li>
        </c:if>
    </c:forEach>

4.循环 <c:forEach>

<c:forEach var="question" items="${requestScope.li}"  varStatus="st">
<%-- <li class="problem"><a href="./carQuestionAction?actionName=detail&id=${question.id}">${question.questionTitle}</a></li> --%>
<li class="problem"><a href="../hudong/question/${question.id}.html">${question.questionTitle}</a></li>
<li class="m-ans"><a href="#">回答(${question.carQuestionAnswerTotal})</a></li>
<li class="time">${question.quotDate}</li>
</c:forEach>

5.日期

<fmt:formatDate value="${dto.questionDate}" pattern="yyyy-MM-dd HH:mm:ss" />

6.函数

${fn:substring(parts.partsName,0,49)}