XSLT is used to transform XML documents into other formats like other XML documents, HTML, text, etc. In Mule, the XSLT transformer component allows transforming XML payloads using XSLT. For example, an XML payload containing employee data can be transformed into a new XML format by applying an XSLT stylesheet file in the Mule flow.

1. XSLT with Mule

2. We often use XSLT in our application to transform XML
payload from one form to another . Mule also supports
XSLT in it’s application with XSLT-Transformer
component.

3. Before we start we must see what an XSLT actually is :-
As per XSLT definition :-
XSLT (Extensible Stylesheet Language Transformations) is a
for transforming XML documents into other XML documents, or other
formats such as HTML for web pages, plain text or into XSL Formatting
Objects, which may subsequently be converted to other formats, such
as PDF PostScript and PNG.
Source :- http://en.wikipedia.org/wiki/XSLT

4. So, XSLT can be use to transform one form of XML to another :-
Here you can see the XSLT is transforming the XML payload into another
XML

5. So, let us try this example in our Mule application
Here we will be using XSLT for transforming the XML payload into
another XML like below :-

6. So let’s consider we have a following flow in our Mule
application:-
As you can see we have used a Http inbound end point followed by a set
payload component and then XSLT transformer.
Here the set payload contain the XML that need to be transform

7. So set payload component contains the following payload :-

8. Our corresponding Mule flow will be as follows :-
<flow name="xsltFlow1" doc:name="xsltFlow1">
<http:inbound-endpoint exchange-pattern="request-response" host="localhost"
port="8081" path="test" doc:name="HTTP"/>
<set-payload
value="&lt;RootElement&gt;&lt;Name&gt;Anirban&lt;/Name&gt;&lt;Department&g
t;ATS&lt;/Department&gt;&lt;Designation&gt;SSE&lt;/Designation&gt;&lt;/RootElem
ent&gt;" doc:name="Set Payload"/>
<mulexml:xslt-transformer
maxIdleTransformers="2" maxActiveTransformers="5" outputEncoding="UTF-8"
doc:name="Transform from outer to inner" xsl-file="Transform.xslt"
encoding="UTF-8" returnClass="java.lang.String" />
</flow>
As you can see we are using XSLT file :- Transform.xslt

9. So, the file Transform.xslt
should be in our src/main/resource folder

10. The file Transform.xslt
Contains following code to transform :-
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes" />
<xsl:template match="/">
<NewRootElement>
<NewName>
<xsl:value-of select="RootElement/Name" />
</NewName>
<NewDepartment>
<xsl:value-of select="RootElement/Department" />
</NewDepartment>
<NewDesignation>
<xsl:value-of select="RootElement/Designation" />
</NewDesignation>
</NewRootElement>
</xsl:template>
</xsl:stylesheet>

11. To test the application we hit the url http://localhost:8081/test in our
browser and we get the following :-
And you can see the XML payload has been transferred to this new XML