JAXB: How to ignore namespace during unmarshalling XML document?
Here is an extension/edit of VonCs solution just in case someone doesn´t want to go through the hassle of implementing their own filter to do this. It also shows how to output a JAXB element without the namespace present. This is all accomplished using a SAX Filter.
Filter implementation:
import org.xml.sax.Attributes;import org.xml.sax.SAXException;import org.xml.sax.helpers.XMLFilterImpl;public class NamespaceFilter extends XMLFilterImpl { private String usedNamespaceUri; private boolean addNamespace; //State variable private boolean addedNamespace = false; public NamespaceFilter(String namespaceUri, boolean addNamespace) { super(); if (addNamespace) this.usedNamespaceUri = namespaceUri; else this.usedNamespaceUri = ""; this.addNamespace = addNamespace; } @Override public void startDocument() throws SAXException { super.startDocument(); if (addNamespace) { startControlledPrefixMapping(); } } @Override public void startElement(String arg0, String arg1, String arg2, Attributes arg3) throws SAXException { super.startElement(this.usedNamespaceUri, arg1, arg2, arg3); } @Override public void endElement(String arg0, String arg1, String arg2) throws SAXException { super.endElement(this.usedNamespaceUri, arg1, arg2); } @Override public void startPrefixMapping(String prefix, String url) throws SAXException { if (addNamespace) { this.startControlledPrefixMapping(); } else { //Remove the namespace, i.e. don´t call startPrefixMapping for parent! } } private void startControlledPrefixMapping() throws SAXException { if (this.addNamespace && !this.addedNamespace) { //We should add namespace since it is set and has not yet been done. super.startPrefixMapping("", this.usedNamespaceUri); //Make sure we dont do it twice this.addedNamespace = true; } }}
This filter is designed to both be able to add the namespace if it is not present:
new NamespaceFilter("http://www.example.com/namespaceurl", true);
and to remove any present namespace:
new NamespaceFilter(null, false);
The filter can be used during parsing as follows:
//Prepare JAXB objectsJAXBContext jc = JAXBContext.newInstance("jaxb.package");Unmarshaller u = jc.createUnmarshaller();//Create an XMLReader to use with our filterXMLReader reader = XMLReaderFactory.createXMLReader();//Create the filter (to add namespace) and set the xmlReader as its parent.NamespaceFilter inFilter = new NamespaceFilter("http://www.example.com/namespaceurl", true);inFilter.setParent(reader);//Prepare the input, in this case a java.io.File (output)InputSource is = new InputSource(new FileInputStream(output));//Create a SAXSource specifying the filterSAXSource source = new SAXSource(inFilter, is);//Do unmarshallingObject myJaxbObject = u.unmarshal(source);
To use this filter to output XML from a JAXB object, have a look at the code below.
//Prepare JAXB objectsJAXBContext jc = JAXBContext.newInstance("jaxb.package");Marshaller m = jc.createMarshaller();//Define an output fileFile output = new File("test.xml");//Create a filter that will remove the xmlns attribute NamespaceFilter outFilter = new NamespaceFilter(null, false);//Do some formatting, this is obviously optional and may effect performanceOutputFormat format = new OutputFormat();format.setIndent(true);format.setNewlines(true);//Create a new org.dom4j.io.XMLWriter that will serve as the //ContentHandler for our filter.XMLWriter writer = new XMLWriter(new FileOutputStream(output), format);//Attach the writer to the filter outFilter.setContentHandler(writer);//Tell JAXB to marshall to the filter which in turn will call the writerm.marshal(myJaxbObject, outFilter);
This will hopefully help someone since I spent a day doing this and almost gave up twice ;)
I have encoding problems with XMLFilter solution, so I made XMLStreamReader to ignore namespaces:
class XMLReaderWithoutNamespace extends StreamReaderDelegate { public XMLReaderWithoutNamespace(XMLStreamReader reader) { super(reader); } @Override public String getAttributeNamespace(int arg0) { return ""; } @Override public String getNamespaceURI() { return ""; }}InputStream is = new FileInputStream(name);XMLStreamReader xsr = XMLInputFactory.newFactory().createXMLStreamReader(is);XMLReaderWithoutNamespace xr = new XMLReaderWithoutNamespace(xsr);Unmarshaller um = jc.createUnmarshaller();Object res = um.unmarshal(xr);
I believe you must add the namespace to your xml document, with, for example, the use of a SAX filter.
That means:
- Define a ContentHandler interface with a new class which will intercept SAX events before JAXB can get them.
- Define a XMLReader which will set the content handler
then link the two together:
public static Object unmarshallWithFilter(Unmarshaller unmarshaller,java.io.File source) throws FileNotFoundException, JAXBException { FileReader fr = null; try { fr = new FileReader(source); XMLReader reader = new NamespaceFilterXMLReader(); InputSource is = new InputSource(fr); SAXSource ss = new SAXSource(reader, is); return unmarshaller.unmarshal(ss); } catch (SAXException e) { //not technically a jaxb exception, but close enough throw new JAXBException(e); } catch (ParserConfigurationException e) { //not technically a jaxb exception, but close enough throw new JAXBException(e); } finally { FileUtil.close(fr); //replace with this some safe close method you have }}