How to add namespace prefix in Java DOM XML builder

Question

I need to set prefix of the element in my xml. I need to print the xml in the format below:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<cars xmlns:dcterms="http://purl.org/dc/terms/" xmlns:msxsl="urn:schemas-microsoft-com:xslt">
<supercars company="Ferrari">
<dcterms:carname type="formula one">Ferrari 101</dcterms:carname>
<msxsl:carname type="sports">Ferrari 202</msxsl:carname>
</supercars>
</cars>

However, I am not able to add the prefix in my XML. What I am getting is this.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<cars xmlns:dcterms="http://purl.org/dc/terms/" xmlns:msxsl="urn:schemas-microsoft-com:xslt">
<supercars company="Ferrari">
<carname type="formula one">Ferrari 101</carname>
<carname type="sports">Ferrari 202</carname>
</supercars>
</cars>

Following is my Java Code:

public static void main(String args[]) {

      try {
         DocumentBuilderFactory dbFactory =
         DocumentBuilderFactory.newInstance();
         DocumentBuilder dBuilder = 
            dbFactory.newDocumentBuilder();

         Document doc = dBuilder.newDocument();

         // root element

         Element rootElement = doc.createElement("cars");
         rootElement.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:dcterms", "http://purl.org/dc/terms/");
         rootElement.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:msxsl", "urn:schemas-microsoft-com:xslt");
         doc.appendChild(rootElement);


         //  supercars element
         Element supercar = doc.createElement("supercars");

         rootElement.appendChild(supercar);

         // setting attribute to element
         Attr attr = doc.createAttribute("company");
         attr.setValue("Ferrari");
       //  supercar.setAttributeNodeNS(attr);
         supercar.setAttributeNode(attr);

         // carname element
         Element carname = doc.createElement("carname");
         Attr attrType = doc.createAttribute("type");
         attrType.setValue("formula one");
         carname.setAttributeNode(attrType);
         carname.appendChild(
         doc.createTextNode("Ferrari 101"));
         supercar.appendChild(carname);

         Element carname1 = doc.createElement("carname");
         Attr attrType1 = doc.createAttribute("type");
         attrType1.setValue("sports");
         carname1.setAttributeNode(attrType1);
         carname1.appendChild(
         doc.createTextNode("Ferrari 202"));
         supercar.appendChild(carname1);

         // write the content into xml file
         TransformerFactory transformerFactory =
         TransformerFactory.newInstance();
         Transformer transformer =
         transformerFactory.newTransformer();
         transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
         transformer.setOutputProperty(OutputKeys.INDENT, "yes");
         transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2"); 
         DOMSource source = new DOMSource(doc);
         StreamResult result =
         new StreamResult(new File("cars.xml"));
         transformer.transform(source, result);
         // Output to console for testing
         StreamResult consoleResult =
         new StreamResult(System.out);
         transformer.transform(source, consoleResult);
      } catch (Exception e) {
         e.printStackTrace();
      }
   }

}

And I checked this link Adding namespace prefix XML String using XML DOM. However, this only talks about the SAX way of doing thing. I need to do this in DOM.

I tried setPrefix method and it is throwing me NAMESPACE_ERR

Answer 1

First of all, make sure you set dbFactory.setNamespaceAware(true);, if you want to work with a DOM supporting namespaces.

Then use createElementNS, e.g. Element carname = doc.createElementNS("http://purl.org/dc/terms/", "dcterms:carname");, to create elements in a namespace. Use the same approach for the element in the other namespace.