JSP标签 jstl 的常用方法 博客分类： Java Web jstljsp标签fnjstl库

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

<%@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

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

 

(3)判断用户是否已经登录

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

 

(4)判断变量

<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

<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

 <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

 <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://java.sun.com/jsp/jstl/functions"%>中.

 (8)让c:forEach 按照顺序输出

 <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

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

 

<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>