How to convert a string to a domsource in Java?

I need some help In my string filedata variable, I store an XmlDocument Now I want to convert this variable to domsource type and use this Code:

DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc = db.parse( new InputSource( new StringReader( filedata ) ) ); 
DOMSource source = new DOMSource(doc);

And through javax xml. transform. Transformer to convert:

Transformer transformer = XMLTransformerFactory.getTransformer(messageType);
 StreamResult res = new StreamResult(flatXML);
 transformer.transform(source,res);

But my flatxml is empty after conversion I checked my doc variable, which contains my XML document and parsed everything If I change my source code to the real path, everything is normal and working properly:

Source source = new StreamSource("c:\\temp\\log\\SMKFFcompleteProductionPlan.xml");

I think my problem lies in this line of code:

DOMSource source = new DOMSource(doc);

But I don't know how to solve this problem

Solution

Why do you want to build a domsource? If all you want is to provide a source of transformation input, it is more efficient to provide a streamsource, which you can do

new StreamSource(new StringReader(fileData))

It is better to also provide systemid Building DOM is a waste of time