JSTL XML Tag x:if Example

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Last Updated on 01 September 2019   |   Print  Email


This post guides you how to use the <x:if> tag in the JSTL XML tags library with code example.

You know, the <x:if> is the XML conditional tag which evaluates the body of the tag if the given XPath expression evaluates to ‘true’.

 

JSTL <x:if> Syntax:

<x:if

  select="<string>"

  var="<string>"

  scope="<string>">   

   ...

</x:if>

 

Attributes:

Name

Required

Description

select

True

XPath expression which determines whether body content is executed or not. If test evaluates to true body content is processed.

var

False

Name of the variable which holds the result of the test condition. The type of this variable is Boolean.

scope

False

Scope of the var.

 

JSTL <x:if> Example:

The following JSP example displays the nodes with salary more than 10000. Note that there is no 'else' construct.

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>  
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/xml" prefix="x"%>
    
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
 "http://www.w3.org/TR/html4/loose.dtd">
<html> 
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <title>&lt;x:if&gt; Demo</title>
  </head>
  <body>
   <h1>&lt;x:if&gt; Demo</h1>
   <c:import 
     url="http://localhost:8080/JSTL-Tag-Reference/tag-types/xml/citizens.xml" 
     var="citizenXML"/>
   <x:parse var="doc" xml="${citizenXML}" />
   <table border="1">
    <x:forEach var="citizen" select="$doc/citizens/citizen">            
        <tr>                            
        <x:if select="salary>10000">
            <td><x:out select="ssn" /></td>
            <td><x:out select="firstname" /></td>
            <td><x:out select="lastname" /></td>
            <td><b><x:out select="role" /></b></td>
            <td><b><x:out select="salary"/></b></td>
        </x:if>                                    
       </tr>        
    </x:forEach>
  </table>
</body>
</html>

 

XML Document (given for reference)

<?xml version='1.0' encoding='UTF-8' standalone='no'?>
<citizens>
    <citizen>
        <ssn>Z345T</ssn>
        <firstname>Cheryl</firstname>
        <lastname>Johnson</lastname>
        <role>Manager</role>
        <salary>12000</salary>
    </citizen>
    <citizen>
        <ssn>Z446T</ssn>
        <firstname>John</firstname>
        <lastname>Smith</lastname>
        <role>Employee</role>
        <salary>1000</salary>
    </citizen>
    <citizen>
        <ssn>Z335T</ssn>
        <firstname>Justin</firstname>
        <lastname>Claire</lastname>
        <role>Senior Manager</role>
        <salary>14000</salary>
    </citizen>
    <citizen>
        <ssn>Z389T</ssn>
        <firstname>Clark</firstname>
        <lastname>Rick</lastname>
        <role>Employee</role>
        <salary>2000</salary>
    </citizen>
</citizens>

 

Output:

x-if

 

Recommended Usage of <x:if> tag:

Particularly useful if we have only one condition to evaluate and we do not need to evaluate else conditions.

 

Other JSTL XML Tags:

forEach  |  out  |  param  |  parse  |  set  |  transform  |  choose, when, otherwise


About the Author:

is certified Java programmer (SCJP and SCWCD). He began programming with Java back in the days of Java 1.4 and has been passionate about it ever since. You can connect with him on Facebook and watch his Java videos on YouTube.



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