JSP Database Connection JSP Standard Tag Library (JSTL)

<x:if> tag

The <x:if> tag is used to judge the value of an XPath expression. If it is true, it will execute the content in its body; if it is false, the content in its body will be ignored.

Syntax format

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

Attribute

The <x:if> tag has the following attributes:

Attribute	Description	Is it necessary	Default value
select	The XPath expression to be calculated	Yes	None
var	Variable to store the condition result	No	None
scope	The scope of the var attribute	No	Page

Example demonstration

The following examples show us 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 Tag</title>
</head>
<body>
<h2>Books Info:</h2>
<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">
   The 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>

The running result is as follows:

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

JSP Standard Tag Library

JSP Database Connection JSP Standard Tag Library (JSTL)

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<x:if> tag

Syntax format

Attribute

Example demonstration