JSP标签 jstl 的常用方法-白红宇

使用开发时,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   
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>  
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>  

(2)截取字符串

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

(3)判断用户是否已经登录

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

(4)判断变量

       Java代码   
<c:choose>  
          
                    <c:when test="${view.totalRecords==0}"><font color="#df625c">0</font> </c:when>  
                    <c:otherwise>  
                        ${view.totalRecords }  
                    </c:otherwise>  
                </c:choose>  
  
<c:choose>  
                    <c:when test="${fn:length(ordersDetail.valid)==0 ||fn:length(fn:trim(ordersDetail.valid))==0 }">无</c:when>  
                    <c:otherwise>${ordersDetail.valid }</c:otherwise>  
                </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   
<table class="frontproductTable" >  
<tr>  
<c:forEach  begin="1" end="2"   varStatus="status">  
<td class="frontproduct" >  
                <table  cellspacing="0" border="0">  
                        <c:forEach var="orders" begin="${(status.count-1)*5 }" end="${(status.count)*5-1 }"  items="${view.recordList}"  
                            varStatus="status">  
                            <tr>  
                                <td rowspan="1">  
                                <a href="<%=path%>/index/product_detail?id=${orders.id }" >  
                                <img width="280px" alt=""  
                                    src="<%=path%>${orders.picPath }" style="width:300px; height:300px; margin:0 20px 10px 10px; border:1px solid #ccc; float:left;">  
                                </a>  
                                </td>  
                                <td rowspan="1">  
                                    <table  >  
                                      
                                      
                                        <tr>  
                                            <td valign="top"><strong>产品名称:</strong></td>  
                                            <td>${orders.itemname }</td>  
                                        </tr>  
                                          
                                        <tr>  
                                            <td colspan="2" ><strong>产品详情:</strong></td>  
                                              
                                        </tr>  
                                        <tr>  
                                              
                                            <td colspan="2" >${orders.desc }</td>  
                                        </tr>  
                                    </table>  
                                </td>  
                            </tr>  
                        </c:forEach>  
  
  
  
                    </table></td>  
  
</c:forEach>  
    </tr>  
</table>  

(6)获取ArrayList的第一个元素

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

(7)获取List的长度

       Html代码   
<ul id="slider_nav">  
                         <c:forEach begin="1" step="1"  end="${fn:length(carouselDiagrams) }" >  
                           <li><a href="#"></a></li>  
                           </c:forEach>  
                         </ul>  

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

(8)让c:forEach 按照顺序输出

       Html代码   
<c:forEach    begin="1" step="1"  end="${fn:length(list) }" varStatus="status" >  
        <li>  
         <label>${list[status.count-1].description }：</label>  
         ${list[status.count-1].value }   
         <label>  </label>  
     </li>  
        </c:forEach>  

(9)循环

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

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