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<X: if> tag

JSP Standard Tag Library JSP Standard Tag Library

<X: if> tag is used to determine the value of an XPath expression, if it is true, then the contents of its body, if its content is false body will be ignored.

Syntax 

<x:if
  select="<string>"
  var="<string>"
  scope="<string>">   
   ...
</x:if>

Attributes

<X: if> tag has the following attributes:

Attributes description If necessary Defaults
select XPath expression to be calculated Yes no
var The results of variable storage conditions no no
scope Scope var attribute no Page

Examples Demo

The following example demonstrates how to use the <x: if> tag: 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ 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 标签</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>

Results are as follows: 


BOOKS INFO:
Document has at least one <book> element. 
Book prices are very high

JSP Standard Tag Library JSP Standard Tag Library