Xpath with prefix

XML file:

<ns:authenticateResponse xmlns:ns='http://webservices.surfbi.fcs.com'>

   <ns:return xmlns:ax27='http://exception.surfbi.fcs.com/xsd' xmlns:ax210='http://dto.surfbi.fcs.com/xsd' type='com.fcs.surfbi.dto.UserDTO'>

      <ax210:first_name>SurfBI</ax210:first_name>

    </ns:return>

</ns:authenticateResponse>

java程式碼, 在使用Xpath時要用xpath.setNamespaceContext()設定Namespace。

DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();

domFactory.setNamespaceAware(true); 

DocumentBuilder builder = domFactory.newDocumentBuilder();

InputStream is = new ByteArrayInputStream(xmlInput.getBytes("UTF-8"));

Document doc = builder.parse(is);

XPathFactory factory = XPathFactory.newInstance();

XPath xpath = factory.newXPath();

xpath.setNamespaceContext(new FCSNamespaceContext());

String nil = xpath.evaluate("//ns:authenticateResponse/ns:return/@xsi:nil", doc);

XPathExpression expr = xpath.compile("//ns:authenticateResponse/ns:return/ax210:first_name");

Object result = expr.evaluate(doc, XPathConstants.NODESET);

NodeList nodes = (NodeList) result;

 for (int i = 0; i < nodes.getLength(); i++) {

  String test = nodes.item(i).getTextContent();

 }

NamespaceContext

public class FCSNamespaceContext implements NamespaceContext{

    public String getNamespaceURI(String prefix)

    {

        if (prefix.equals("ns"))

            return "http://webservices.surfbi.fcs.com";

        else if (prefix.equals("ax210"))

            return "http://dto.surfbi.fcs.com/xsd";

        else if (prefix.equals("ax27"))

            return "http://exception.surfbi.fcs.com/xsd";

        else if (prefix.equals("xsi"))

            return "http://www.w3.org/2001/XMLSchema-instance";

        else

            return XMLConstants.NULL_NS_URI;

    }

    public String getPrefix(String namespace)

    {

        if (namespace.equals("http://webservices.surfbi.fcs.com"))

            return "ns";

        else if (namespace.equals("http://dto.surfbi.fcs.com/xsd"))

            return "ax210";

        else if (namespace.equals("http://exception.surfbi.fcs.com/xsd"))

            return "ax27";

        else if (namespace.equals("http://www.w3.org/2001/XMLSchema-instance"))

            return "xsi";

        else

            return null;

    }

    public Iterator getPrefixes(String namespace)

    {

        ArrayList list = new ArrayList();

        if ( namespace.equals( "http://webservices.surfbi.fcs.com")) {

          list.add( "ns");

        } else if ( namespace.equals( "http://dto.surfbi.fcs.com/xsd")) 

            list.add( "ax210");

        return list.iterator();

    }

}