I have problems unmarshalling an object from a org.w3c.dom.Document object.
I create a simple org.w3c.dom.Document object, and then I try to
unmarshall it, but it reports this error:
>Exception in thread "main" java.lang.NullPointerException
> at com.sun.xml.bind.unmarshaller.SAXUnmarshallerHandlerImpl.startElement
>(SAXUnmarshallerHandlerImpl.java:87)
> at com.sun.xml.bind.unmarshaller.DOMScanner.visit(DOMScanner.java:109)
> at com.sun.xml.bind.unmarshaller.DOMScanner.parse(DOMScanner.java:64)
> at com.sun.xml.bind.unmarshaller.UnmarshallerImpl.unmarshal(Unmarshaller
>Impl.java:149)
> at TestB.createObject(TestB.java:39)
> at TestB.main(TestB.java:19)
But, if I create the same Document object, I save it into a file,
and I reload it from this file, having again a Document object
(which should be the same),
then I can unmarshall it successfully.
What can be the problem?
-----------------------------------------
import org.xml.sax.*;
import org.w3c.dom.*;
import javax.xml.parsers.*;
import java.io.*;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.Marshaller;
public class TestB
{
public static void main(String[] args) throws Exception
{
Document doc = createDoc();
System.out.println(doc.getDocumentElement());
//doc = saveAndReload(doc); //If I do this strange thing, then it works
createObject(doc);
}
static Document createDoc() throws Exception
{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true);
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.newDocument();
Element element = doc.createElement("WozRequest");
element.setAttribute("action", "value");
doc.appendChild(element);
return doc;
}
static void createObject(Document doc) throws Exception
{
JAXBContext jc = JAXBContext.newInstance("wozObject.request");
Unmarshaller u = jc.createUnmarshaller();
Object o = u.unmarshal( doc );
}
static Document saveAndReload(Document doc) throws Exception
{
String fileName = "root.xml";
PrintWriter out = new PrintWriter(new FileWriter(fileName, false));
out.println(doc.getDocumentElement());
out.close();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true);
DocumentBuilder db = dbf.newDocumentBuilder();
doc = db.parse(new File(fileName));
return doc;
}
}
-----------------------------------------
Regards,
David