CODEWITHSUNDEEP
javaxmlxml-parsing
L4zl0w
L4zl0w

Reputation: 1097

Rename root node of XML (with namespace prefix) in Java

I'm trying to use the renameNode() method of the org.w3c.dom.Document class to rename the root node of an XML document.

My code is similar to this:

xml.renameNode(Element, "http://newnamespaceURI", "NewRootNodeName");

The code does rename the root element but doesn't apply the namespace prefix. Hard-coding the namespace prefix would not work as it has to be dynamic.

Any ideas why it is not working?

Many thanks

Upvotes: 2

Views: 7621

Answers (2)

L4zl0w
L4zl0w

Reputation: 1097

I managed to sort this by looking up the namespace prefix like this:

String namespacePrefix = rootelement.lookupPrefix("http://newnamespaceURI");

and then using this with the renameNode method:

xml.renameNode(Element, "http://newnamespaceURI", namespacePrefix + ":" + "NewRootNodeName");

Upvotes: 3

vanje
vanje

Reputation: 10383

I tried it with JDK 6:

public static void main(String[] args) throws Exception {
  // Create an empty XML document
  Document xml = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();

  // Create the root node with a namespace
  Element root = xml.createElementNS("http://oldns", "doc-root");
  xml.appendChild(root);

  // Add two child nodes. One with the root namespace and one with another ns    
  root.appendChild(xml.createElementNS("http://oldns", "child-node-1"));
  root.appendChild(xml.createElementNS("http://other-ns", "child-node-2"));

  // Serialize the document
  System.out.println(serializeXml(xml));

  // Rename the root node
  xml.renameNode(root, "http://new-ns", "new-root");

  // Serialize the document
  System.out.println(serializeXml(xml));
}

/*
 * Helper function to serialize a XML document.
 */
private static String serializeXml(Document doc) throws Exception {
  Transformer transformer = TransformerFactory.newInstance().newTransformer();
  Source source = new DOMSource(doc.getDocumentElement());
  StringWriter out = new StringWriter();
  Result result = new StreamResult(out);
  transformer.transform(source, result);
  return out.toString();
}

The output is (formatting added by me):

<doc-root xmlns="http://oldns">
  <child-node-1/>
  <child-node-2 xmlns="http://other-ns"/>
</doc-root>

<new-root xmlns="http://new-ns">
  <child-node-1 xmlns="http://oldns"/>
  <child-node-2 xmlns="http://other-ns"/>
</new-root>

So it works like expected. The root node has a new local name and new namespace while the child nodes remains the same including their namespaces.

Upvotes: 1

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