Performance issue: Java and XSLT

Question

I have a performance issue concerning Java and XSLT: my goal is to transform an xml file (source.xml)
by using a given xsl file (transformation.xsl). As result I would like to get a String object, in which the result
of the transformation (html-code) is in, so that I can display it in a browser. The problem is the long time
it takes for the code below to run through.
xml = new File("C:\\source.xml");
xmlSource = new StreamSource(xml);
xslt = new File("C:\\transformation.xsl");
StreamSource xsltSource = new StreamSource(xslt);
TransformerFactory transFact = TransformerFactory.newInstance();
trans = transFact.newTransformer(xsltSource);
StringWriter stringWriter = new StringWriter();
StreamResult streamResult = new StreamResult(stringWriter);
trans.transform(xmlSource, streamResult);
String output = stringWriter.toString();
stringWriter.close();
Before, I made the same transformation in an xml development environment, named Cooktop
(see http://xmlcooktop.com/). The transformation took about 2 seconds. With the code above in Java it
takes about 20 seconds.
Is there a way to make the transformation in Java faster?
Thanks in advance,
Marcello
Oldenburg, Germany
[email protected]

Answer 1

I haven't tried it but the if you can use java 6, you could try the new stax (StAX) with the XML stream loading..
Take a look at:
http://javaboutique.internet.com/tutorials/staxxsl/
Then, you could cache the xslt in templates:
---8<---
templates = transformerFactory.newTemplates( xsltSource );
Transformer transformer = templates.newTransformer();
(here you could probobly also cache the Transformer object but I think it's it's not thread safe so it's a little tricker..)
StreamResult result = new StreamResult( System.out );
          transformer.transform(xmlSource, result);
And, don't transform your result to a string, use a Stream or something, then the transformer could start pumping out html while working, and if you get a out of memory error it looks like you have a pretty big xml file...
If you use jsp you could try the build in jsp taglib for xml which I think is rather good and they have support for varReader which implements the StreamSource iirc.
/perty