Question

I have a DOM-Document and I extract a certain node using XPath. After that I want to serialize that node to XML. I am using the following code:

TransformerFactory
        .newInstance()
        .newTransformer()
        .transform(new DOMSource(node),
                new StreamResult(getOutputStream()));

This works in a simple document, but consider the following document:

<xml xmlns:foo="...">
  <bar foo:bar="xyz" />
</xml>

In this case if I want to serialize the node “bar”, then the code above breaks, because the transformer says:

Namespace for prefix ‘foo’ has not been declared

How can I get the transformer to copy the namespace definitions into the new document?

Answer 1

Set your DocumentBuilderFactory to be namespace aware.

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);