java - how to marshal a JAXB object to org.w3c.dom.Document?

Question

This gives me a Document object with a top level node with no child nodes:

public static Document getDocument(Object jaxb)
{
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    //dbf.setNamespaceAware(true);
    Document doc = dbf.newDocumentBuilder().newDocument(); 

    JAXBContext context = JAXBContext.newInstance(jaxb.getClass());
    context.createMarshaller().marshal(jaxb, doc);

    return doc;
}

This is the workaround, which seems even more inefficient, since it converts to String and then to Document.

public static Document getDocument(Object jaxb)
{                           
    StringWriter writer = new StringWriter();       
    JAXBContext context = JAXBContext.newInstance(jaxb.getClass());
    context.createMarshaller().marshal(jaxb, writer);

    return DocumentBuilderFactory.newInstance().newDocumentBuilder().
parse(new InputSource(new StringReader(writer.toString()));
}

Is it possible to accomplish what I'm trying to accomplish?

Answer 1

What you are doing should work. Here is an example:

Domain Model (Foo)

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Foo {

    private String bar;

    public String getBar() {
        return bar;
    }

    public void setBar(String bar) {
        this.bar = bar;
    }

}

Demo

import javax.xml.bind.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

public class Demo {

    public static void main(String[] args) throws Exception {
        // Create the JAXBContext
        JAXBContext jc = JAXBContext.newInstance(Foo.class);

        // Create the Object
        Foo foo = new Foo();
        foo.setBar("Hello World");

        // Create the Document
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        Document document = db.newDocument();

        // Marshal the Object to a Document
        Marshaller marshaller = jc.createMarshaller();
        marshaller.marshal(foo, document);

        // Output the Document
        TransformerFactory tf = TransformerFactory.newInstance();
        Transformer t = tf.newTransformer();
        DOMSource source = new DOMSource(document);
        StreamResult result = new StreamResult(System.out);
        t.transform(source, result);
    }

}

Output

<?xml version="1.0" encoding="UTF-8" standalone="no"?><foo><bar>Hello World</bar></foo>