JSP jstl-<x:when> 标记

jstl-<x:when> 标记

<x:choose>标签的运作方式类似于Java的switch语句。有了这个，您可以在多种选择之间进行选择。如果switch语句具有case语句，则<x：choose>标记具有<x：when>标记。以类似的方式，switch语句具有default子句以指定默认操作，而≪x：choose>标记具有≪x：otherwise>标记作为默认子句。

属性

属性	描述	必需	默认值
select	要评估的XPath表达式	是	没有

示例

以下示例将显示如何使用<x：when>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:choose Tags</title>
   </head>

   <body>
      <h3>Books Info:</h3>
      
      <c:set var = "xmltext">
         <books>
            <book>
               <name>Padam History</name>
               <author>MOO</author>
               <price>100</price>
            </book>
            
            <book>
               <name>Great Mistry</name>
               <author>NUHA</author>
               <price>2000</price>
            </book>
         </books>
      </c:set>

      <x:parse xml = "${xmltext}" var = "output"/>
      <x:choose>
         <x:when select = "$output//book/author = 'MOO'">
            Book is written by MOO
         </x:when>
         
         <x:when select = "$output//book/author = 'NUHA'">
            Book is written by NUHA
         </x:when>
         
         <x:otherwise>
            Unknown author.
         </x:otherwise>
      </x:choose>

   </body>
</html>

上面的代码将产生以下结果-


Books Info:

Book is written by MOO