jstl常用标签

需要导入<%@ taglib prefix="c"uri="http://java.sun.com/jstl/core" %>
If标签
<c:set var="a" value="hello"/>  
<c:if test="${not empty a }">  
    <c:out value="${a }"/>  
</c:if>  




Choose标签
<c:set var="score" value="${param.score }"/>  
<c:choose>  
    <c:when test="${score > 100 || score < 0}">错误的分数：${score }</c:when>  
    <c:when test="${score >= 90 }">A级</c:when>  
    <c:when test="${score >= 80 }">B级</c:when>  
    <c:when test="${score >= 70 }">C级</c:when>  
    <c:when test="${score >= 60 }">D级</c:when>  
    <c:otherwise>E级</c:otherwise>  
</c:choose> 


forEach标签


1遍历变量
<c:set var="sum" value="0" />   
<c:forEach var="i" begin="1" end="10">   
    <c:set var="sum" value="${sum + i}" />   
</c:forEach>  
<c:out value="sum = ${sum }"/>  
<c:set var="sum" value="0" />  
<c:forEach var="i" begin="1" end="10" step ="2">  
    <c:set var="sum" value="${sum + i}" />  
</c:forEach>  
<c:out value="sum = ${sum }"/> 


2遍历集合
<%  
String[] names = {"zhangSan", "liSi", "wangWu", "zhaoLiu"};  
pageContext.setAttribute("ns", names);  
%>  
<c:forEach var="item" items="${ns }">  
    <c:out value="name: ${item }"/><br/>  
</c:forEach> 




fmt标签库:
需要导入<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %> 


将时间格式化
<%  
    Date date = new Date();  
    pageContext.setAttribute("d", date);  
%>  
<fmt:formatDate value="${d }" pattern="yyyy-MM-dd HH:mm:ss"/>