jsp基本知识的讲解

1、请说明什么是EL？EL和JSP<%= expr%>的区别是什么？ 解释下面的EL的意义： ${user.name} ${user.address.zipcode} ${user.hobbies[0]} ${user["id"]} ${param.age} ${cookie.username} ${user} ${!empty cart} ${sessionScope.cart} ${initParam.email} ${pageContext.request.contextPath} 2、请写出JSTL核心标签库中的下面的标签的用法，并说明起作用 a)forEach <c:forEach var="i" begin="" end="" step=""> body ${i} </c:forEach> <c:forEach var="item" items="${}" varStatus="status"> body ${item.id} </c:forEach> b)if <c:if test="${param.} " var="rst"> <h1>hello<h1> </c:if> c)choose when otherwise <c:choose> <c:when test=" "> body </c:when> <c:when test=" "> body </c:when> <c:otherwise> body </c:otherwise> </c:choose> d)set remove <c:set var="" scope="">value to be set</c:set> <c:set var="" scope="" value="" /> <c:remove var="" scope="" /> e)url <c:url value=" " />