Jaxp namespaces in document elements

Question

I am trying to use Java to access xml items using XPath.
I am OK with an xml document with name spaces in root element.
But not namespaces declared in elements.
Typically see two documents at
http://www.w3schools.com/XML/xml_namespaces.asp
Under
XML Namespaces - The xmlns Attribute
Quote "Namespaces can be declared in the elements where they are used or in the XML root element:"
My Xpath is "/root/h:table/h:tr/h:td"
This works OK for second document with namespaces in root element.
But not the first document with namespaces in the elements.
I have tried using lookupNamespaceURI but this only seems to process root element.
It's hair pulling time!
Any Ideas
Thanks

Answer 1

OK messy but ..
Set the line
XPathDemo xPathDemo = new XPathDemo("C:/opt/XpathDemo/w32.XML");to be either of the two w3schools example quoted previously.
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import javax.xml.XMLConstants;
import javax.xml.namespace.NamespaceContext;
import javax.xml.parsers.DocumentBuilder;  
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class XPathDemo
    public class UniversalNamespaceResolver implements NamespaceContext
        // the delegate
        private Document sourceDocument;
         * This constructor stores the source document to search the namespaces in it.
         * @param document source document
        public UniversalNamespaceResolver(Document document)
            sourceDocument = document;
         * The lookup for the namespace uris is delegated to the stored document.
         * @param prefix to search for
         * @return uri
        public String getNamespaceURI(String prefix)
            String retVal;
            if (prefix.equals(XMLConstants.DEFAULT_NS_PREFIX))
                retVal = sourceDocument.lookupNamespaceURI(null);
            else
                retVal = sourceDocument.lookupNamespaceURI(prefix);
            return retVal;
         * This method is not needed in this context, but can be implemented in a similar way.
        public String getPrefix(String namespaceURI)
            return sourceDocument.lookupPrefix(namespaceURI);
        public Iterator getPrefixes(String namespaceURI)
            // not implemented yet
            return null;
    public XPathDemo(String fileName)
        try
            String dataFileName = "C:/opt/XpathDemo/tmp.txt";
            File f = new File(dataFileName);
            PrintWriter out = new PrintWriter(f);
            generateData(out, fileName);
            out.flush();
            out.close();
        catch (XPathExpressionException xp)
            System.out.println("Exception expression cannot be compiled : " + xp.getMessage());
        catch (NullPointerException np)
            System.out.println("expression is null : " + np.getMessage());
        catch (Exception e)
            System.out.println("General exception : " + e.getMessage());
    public void generateData(PrintWriter out, String fileName) throws ParserConfigurationException, SAXException, IOException,
        XPathExpressionException
        DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
        domFactory.setNamespaceAware(true); // never forget this!
        DocumentBuilder builder = domFactory.newDocumentBuilder();
        Document doc = builder.parse(fileName);
        XPathFactory factory = XPathFactory.newInstance();
        XPath xpath = factory.newXPath();
        xpath.setNamespaceContext(new UniversalNamespaceResolver(doc));
        System.out.println("Setting expr");
        XPathExpression expr = xpath.compile("/root/h:table/h:tr/h:td");
        if (expr != null)
            Object result = expr.evaluate(doc, XPathConstants.NODESET);
            if (result != null)
                NodeList nodes = (NodeList) result;
                System.out.println("Looping through " + nodes.getLength());
                for (int i = 0; i < nodes.getLength(); i++)
                    System.out.println("i = " + i);
                    Node thisNode = nodes.item(i);
                    NodeList thisNode2 = thisNode.getChildNodes();
                    Node xx = thisNode2.item(0);
                    String val = xx.getNodeValue();
                    System.out.println("Value : '" + val + "'");
            else
                System.out.println("Result was NULL");
        else
            System.out.println("Expr was NULL");
    public static void main(String[] args)
        XPathDemo xPathDemo = new XPathDemo("C:/opt/XpathDemo/w32.XML");
        System.out.println("Main complete!");
}