<x:choose>, <x:when>, <x:otherwise> 标签

<x:choose>标签与Java switch语句有相同的功能。switch语句有case语句，而<x:choose>标签有<x:when>标签。switch语句有default语句，而<x:choose>标签有<x:otherwise>标签。

语法格式

  1. <x:choose>
  2.  <x:when select="<string>">
  3.      ...
  4.  </x:when>
  5.  <x:when select="<string>">
  6.      ...
  7.  </x:when>
  8.      ...
  9.      ...
  10.  <x:otherwise>
  11.      ...
  12.  </x:otherwise>
  13. </x:choose>

属性

  • 没有属性。
  • 的属性在下表中给出。
  • 没有属性。

<x:when>标签的属性：

属性描述是否必要默认值
select条件是无

实例演示

  1. <%@ page language="java" contentType="text/html; charset=UTF-8"
  2.     pageEncoding="UTF-8"%>
  3. <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
  4. <%@ taglib prefix="x" uri="http://java.sun.com/jsp/jstl/xml" %>
  6. <html>
  7. <head>
  8.   <title>JSTL x:choose 标签</title>
  9. </head>
  10. <body>
  11. <h3>Books Info:</h3>
  13. <c:set var="xmltext">
  14.   <books>
  15.     <book>
  16.       <name>Padam History</name>
  17.       <author>ZARA</author>
  18.       <price>100</price>
  19.     </book>
  20.     <book>
  21.       <name>Great Mistry</name>
  22.       <author>NUHA</author>
  23.       <price>2000</price>
  24.     </book>
  25.   </books>
  26. </c:set>
  28. <x:parse xml="${xmltext}" var="output"/>
  29. <x:choose>
  30.    <x:when select="$output//book/author = 'ZARA'">
  31.       Book is written by ZARA
  32.    </x:when>
  33.    <x:when select="$output//book/author = 'NUHA'">
  34.       Book is written by NUHA
  35.    </x:when>
  36.    <x:otherwise>
  37.       Unknown author.
  38.    </x:otherwise>
  39. </x:choose>
  41. </body>
  42. </html>

运行结果如下：

  1. BOOKS INFO:
  2. Book is written by ZARA