NamespaceContext and using namespaces with XPath

Question

Resolving an xpath that includes namespaces in Java appears to require the use of a NamespaceContext object, mapping prefixes to namespace urls and vice versa.

Answer 1

If you are using Jersey 2 and only have a default XML namespace (xmlns="..."), you can use SimpleNamespaceResolver:

DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
docBuilderFactory.setNamespaceAware(true);
DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();

Document document = docBuilder.parse(new File("document.xml"));
String query = "/t:Outer/t:Inner";

XPath xpath = XPathFactory.newInstance().newXPath();
String xmlns = document.getDocumentElement().getAttribute("xmlns");
xpath.setNamespaceContext(new SimpleNamespaceResolver("t", xmlns));

NodeList nodeList = (NodeList) xpath.evaluate(query, document, XPathConstants.NODESET);

//nodeList will contain the  element

You can also specify xmlns manually if you want.