el jstl and simple to use

jsp using el and jstl

 1 <%
 2         request.setAttribute("name", "测试");
 3     %>
 4     <!--   属性名           属性值        存储域 -->
 5     <c:set var="age" value="17" scope="request">
 6     </c:set>
 7     <!--     if标签 -->
 8     <c:out value="${name}"></c:out>
 9     <br />
10     <c:if test="${name!=null }">
11     是
12     </c:if>
13     <br />
14     <!--     if和else -->
15     <c:choose>
16         <c:when test="${age<18}">
17             <font color="red">未成年</font>
18         </c:when>
19         <c:otherwise>
20             <font color="green">已成年</font>
21         </c:otherwise>
22     </c:choose>
23     <br />
24     <%
25         List<String> list = new ArrayList<>();
26         list.add("循环1");
27         list.add("循环2");
28         list.add("循环3"30);
         List.add ( "cycle 4"29);
         request.setAttribute ( "List" , List);
 31 is      %>
 32      ! <- forEach var tag cycles begin traversing the index beginning from the end where the end where ->
 33 is      <C: forEach var = "I" begin = ". 1 "End =". 5 ">
 34 is          $ {I} <br />
 35      </ C: forEach>
 36      <- ITME is set to traverse ->!
 37 [      <C: forEach items =" $ {List} " = var "S">
 38 is      $ {S} <br />
 39      </ C: forEach>