如何检查xml中是否存在标签

Question

my XML is -

<app>
 <data>
    <lang>en</lang>
 </data>
</app>

I want to check, whether 'lang' tag/element is present or not. I am using below code to check it, but I think it is not working. -

<xsl:if test="app/data/lang">
<xsl:call-template name="xyz" /></xsl:if>

I am not able to understand what I am doing wrong here. I referred this page of stackoverflow. Please suggest any other way do solve this. Thanks in advance!

Answer -

After doing many changes I got one solution. I made a small change to solve this issue. I added '/' before 'app'.

<xsl:if test="/app/data/lang">
  <xsl:call-template name="xyz" />
</xsl:if>

Thanks everyone for sharing their solutions.

Answer 1

You can use XSLT checking . Choose and When is good for doing it Below is the sample code

   <xsl:choose>
          <xsl:when test="app/data/lang">
                 *write what ever you want*
          </xsl:when>
   </xsl:choose>

Answer 2

Eg in a template matching app you can use <xsl:if test="data/lang"> .

The tag mentioned must exist, although it may be empty.

A suspected reason that your script failed is that the current object may be such that app/data/lang path finds nothing.

For a working example see http://xsltransform.net/bEJaog9

To get the "Absent" case, change eg the name of source lang tag to any other.

Answer 3

Based on my understanding giving this answer, consider this might be your XML

<Data>
    <Record>
     <AddInfo>
     </AddInfo>
    </Record>
</Data>

you need to check AddInfo tag based on you have to call-template, then this would be the XSL need to form

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="text"/>

  <xsl:template match="Data/Record">
      <xsl:choose>
        <xsl:when test="AddInfo">Present</xsl:when>
        <xsl:otherwise>Not Present</xsl:otherwise>
      </xsl:choose>
  </xsl:template>
</xsl:stylesheet>

Based on present or not present, you provide your condition. More stuff related to call-template Link here

Answer 4

I made a small change to solve this. I added '/' before 'app'.

<xsl:if test="/app/data/lang">
  <xsl:call-template name="xyz" />
</xsl:if>