How should I select a XML "namespaced" node using org.w3c.dom.Node.getNamedItemNS(nsUri, name)?

This is the xml:

<xml xmlns:log="http://sample.com">

  <test log:writer="someWriter" />

</xml>

I am trying to get the attribute value 开发者_StackOverflowof "log:writer" using the following line of code:

currentNode.getAttributes().getNamedItemNS("log", "writer")

I tried also to place the xmlns:log="http://sample.com" declaration on the "test" node, but I receive always a NullPointerException. The DocumentBuilderFactory used for the Document has also the setNamespaceAware enabled. Any hint?

---

getNamedItemNS takes the namespaceURI as its first parameter (i.e. http://sample.com), not the prefix (log).

Edit:

Here's a test case in full. This prints out "Attribute value is someWriter". Tested using Xerces as the XML library. Does this work for you?

import java.io.IOException;
import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;


public class GetNamedItemNSTester
{
    public static void main(String[] args)
    {
        new GetNamedItemNSTester();     
    }

    String xml = "<xml xmlns:log=\"http://sample.com\">\n" +
            "\n" +
            "<test log:writer=\"someWriter\" />\n" +
            "\n" +
            "</xml>";


    public GetNamedItemNSTester()
    {
        StringReader xmlReader = new StringReader(xml);
        try
        {
            DocumentBuilderFactory factory =
                DocumentBuilderFactory.newInstance();
            factory.setNamespaceAware(true);
            DocumentBuilder builder = factory.newDocumentBuilder();
            Document doc = builder.parse(new InputSource(xmlReader));

            Element currentNode =
                (Element)doc.getElementsByTagName("test").item(0);
            String attributeValue = currentNode.getAttributes()
                .getNamedItemNS("http://sample.com", "writer").getNodeValue();
            System.out.println("Attribute value is " + attributeValue);
        }
        catch (ParserConfigurationException e)
        {
            e.printStackTrace();
        }
        catch (SAXException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        finally
        {
            xmlReader.close();
        }
    }
}