JSTL代碼庫

一：引入

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

二：if語句

      1.<li>條件控制標籤：c:if</li>

    <c:if test="${v1 lt v2}">
        v1小於v2<br>
    </c:if>

       2.<li>條件控制標籤：c:choose,c:when,c:otherwise</li>

<c:choose>
       <c:when test="${v1 gt v2}">
            v1大於v2<br>
       </c:when>
       <c:otherwise>
            v1小於v2<br>
       </c:otherwise>
 </c:choose>

       3.<li>演示循環控制標籤：forEach</li>

<table border="1">
        <tr>
            <td>用戶名稱</td>
        </tr>
        <c:choose>
            <c:when test="${empty users}">
                <tr>
                    <td colspan="3">沒有符合條件的數據</td>
                </tr>
            </c:when>
            <c:otherwise>
                <c:forEach items="${users}" var="user">
                    <tr>
                        <td>${user.username }</td>
                    </tr>
                </c:forEach>
            </c:otherwise>
        </c:choose>
    </table>