JSP jstl-<x:if> 标记

  • jstl-<x:if> 标记

    <x:if>标签计算一个测试XPath表达式,并且如果它是真实的,它处理它的身体。如果测试条件为假,则忽略主体。
  • 属性

    属性 描述 必需 默认值
    select 要评估的XPath表达式 没有
    var 用于存储条件结果的变量名称 没有
    scope var属性中指定的变量作用域 Page
  • 示例

    以下示例将显示如何使用<x:if>标记-
    
    <%@ taglib prefix = "c" uri = "http://java.sun.com/jsp/jstl/core" %>
    <%@ taglib prefix = "x" uri = "http://java.sun.com/jsp/jstl/xml" %>
    
    <html>
       <head>
          <title>JSTL x:if Tags</title>
       </head>
    
       <body>
          <h3>Books Info:</h3>
    
          <c:set var = "xmltext">
             <books>
                <book>
                   <name>Padam History</name>
                   <author>ZARA</author>
                   <price>100</price>
                </book>
                   
                <book>
                   <name>Great Mistry</name>
                   <author>NUHA</author>
                   <price>2000</price>
                </book>
             </books>
          </c:set>
    
          <x:parse xml = "${xmltext}" var = "output"/>
          <x:if select = "$output//book">
             Document has at least one <book> element.
          </x:if>
          <br />
          
          <x:if select = "$output/books[1]/book/price > 100">
             Book prices are very high
          </x:if>
    
       </body>
    </html>
    
    上面的代码将产生以下结果-
    
    Books Info:
    
    Document has at least one <book> element.
    
    Book prices are very high