JSP标签 jstl 的常用方法

使用Java Web开发时,会经常使用jstl,它是一个轻量级的标签库,不像struts2 那样庞大.

现在总结jstl的常用场景

(1)如何在页面中引入jstl库

Java代码  

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

(2)截取字符串

Java代码  

1. <td>${fn:substring(ordersDetail.toothOrders.inDate,0,19)   }</td>  

(3)判断用户是否已经登录

Java代码  

1.  <c:if test="${sessionScope.logined!=null && sessionScope.user.role_id=='1'}">  
2.             <a href="<%=path%>/orders/export" class="daoc"  onclick="return com.whuang.hsj.confirmDelete('确定要导出吗?')"  >导 出(快)</a>&nbsp;  
3. <a href="<%=path%>/orders/exportSlow" class="daoc"  onclick="return com.whuang.hsj.confirmDelete('确定要导出吗(包含产品详情)?')" >导 出(慢)</a>  
4. </c:if>  

(4)判断变量

Java代码  

1. <c:choose>  
2.           
3.                     <c:when test="${view.totalRecords==0}"><font color="#df625c">0</font> </c:when>  
4.                     <c:otherwise>  
5.                         ${view.totalRecords }  
6.                     </c:otherwise>  
7.                 </c:choose>  
8.   
9. <c:choose>  
10.                     <c:when test="${fn:length(ordersDetail.valid)==0 ||fn:length(fn:trim(ordersDetail.valid))==0 }">无</c:when>  
11.                     <c:otherwise>${ordersDetail.valid }</c:otherwise>  
12.                 </c:choose>  

 (5)c:forEach 的begin 是从零开始的

注意:c:forEach 的begin 不是从1 开始的

Java代码  

1. <table class="frontproductTable" >  
2. <tr>  
3. <c:forEach  begin="1" end="2"   varStatus="status">  
4. <td class="frontproduct" >  
5.                 <table  cellspacing="0" border="0">  
6.                         <c:forEach var="orders" begin="${(status.count-1)*5 }" end="${(status.count)*5-1 }"  items="${view.recordList}"  
7.                             varStatus="status">  
8.                             <tr>  
9.                                 <td rowspan="1">  
10.                                 <a href="<%=path%>/index/product_detail?id=${orders.id }" >  
11.                                 <img width="280px" alt=""  
12.                                     src="<%=path%>${orders.picPath }" style="width:300px; height:300px; margin:0 20px 10px 10px; border:1px solid #ccc; float:left;">  
13.                                 </a>  
14.                                 </td>  
15.                                 <td rowspan="1">  
16.                                     <table  >  
17.                                       
18.                                       
19.                                         <tr>  
20.                                             <td valign="top"><strong>产品名称:</strong></td>  
21.                                             <td>${orders.itemname }</td>  
22.                                         </tr>  
23.                                           
24.                                         <tr>  
25.                                             <td colspan="2" ><strong>产品详情:</strong></td>  
26.                                               
27.                                         </tr>  
28.                                         <tr>  
29.                                               
30.                                             <td colspan="2" >${orders.desc }</td>  
31.                                         </tr>  
32.                                     </table>  
33.                                 </td>  
34.                             </tr>  
35.                         </c:forEach>  
36.   
37.   
38.   
39.                     </table></td>  
40.   
41. </c:forEach>  
42.     </tr>  
43. </table>  

(6)获取ArrayList的第一个元素

Html代码  

1. <div class="slider-item"><img src="<%=path%>${carouselDiagrams[0].picPath}"/></div>  
2.              <c:forEach var="carouselDiagram" begin="1" items="${carouselDiagrams}" varStatus="status">  
3.          <div class="slider-item"><img id="img_id_${status.count}" />  </div>  
4.          
5.                 </c:forEach>  

(7)获取List的长度

Html代码  

1. <ul id="slider_nav">  
2.                          <c:forEach begin="1" step="1"  end="${fn:length(carouselDiagrams) }" >  
3.                            <li><a href="#"></a></li>  
4.                            </c:forEach>  
5.                          </ul>  

注意:fn:length 在<%@ taglib prefix="fn" uri="http://Java.sun.com/jsp/jstl/functions"%>中.

 (8)让c:forEach 按照顺序输出

Html代码  

1. <c:forEach    begin="1" step="1"  end="${fn:length(list) }" varStatus="status" >  
2.         <li>  
3.          <label>${list[status.count-1].description }：</label>  
4.          ${list[status.count-1].value }   
5.          <label>  </label>  
6.      </li>  
7.         </c:forEach>  

 (9)循环

Html代码  

1. <c:forEach      items="${commonDictionaries }" var="commonDictionary"  varStatus="status" >  
2.                             <section  >  
3.                                 <a href="#" ><h3>${commonDictionary.value } <span style="display: none" >></span> </h3></a>  
4.                             </section>  
5.                             </c:forEach>   

Html代码  

1. <c:forEach varStatus="status" items="${view.recordList }"  
2.             var="paperNews">  
3.             <li style="margin-right: 10px"><!--<a href="#"><img src="${paperNews.pic }"  
4.                     alt="${paperNews.title }" class="alignleft" /></a>  
5.                 <p>  
6.                     <span>发表日期${paperNews.releaseTimeStr }</span> <a href="#">${paperNews.title }</a>  
7.                 </p>  <span class="rating"><span style="width: 80%;"></span></span> -->  
8.                 <img src="${paperNews.pic }" alt="${paperNews.title }" class="alignleft aHref"  onclick="tabSelect('<%=path%>/news/${paperNews.id }?1=1',this,false)"  />  
9.                                     <h6 class="regular"><a  class="aHref" onclick="tabSelect('<%=path%>/news/${paperNews.id }?1=1',this,false)"  >${paperNews.title }</a></h6>  
10.                                     <span class="meta">${paperNews.releaseTimeStr }   <!-- \\   <a href="#">World News.</a>   \\   <a href="#">No Coments.</a> --></span>  
11.                                     <p>${fn:substring(paperNews.content,0,60)}...</p>  
12.                 </li>  
13.                   
14.                   
15.         </c:forEach>