Java XML transformer error on attribute : Namespace for prefix 'req' has not been declared

Question

My XML in test.xml :

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<record>
    <req1:name>john</req1:name>
    <age req:valid="f">57</age>
</record>

My Java code:

DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document  = documentBuilder.parse(getClass().getClassLoader().getResourceAsStream("test.xml"));
StringWriter writer = new StringWriter();
StreamResult result = new StreamResult(writer);
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.transform(new DOMSource(document),result);
System.out.println(writer.toString());

When running the transformer.transform will throw an exception

Namespace for prefix 'req' has not been declared

If I remove the req: prefix from the attribute it's working. There is no exception for the req1 prefix. The exception only appears for attributes.

Is there a way disable that kind of validation ?

I tried with

documentBuilderFactory.setValidating(false);
documentBuilderFactory.setNamespaceAware(false);

but it changes nothing.

Answer 1

namespace needs to be declared

try

<record xmlns:req="http://your-ns-url">
<!-- ... -->
</record>

Edit:

If you just want to get rid of the exception add the namspace to the doc root before transforming to string

Element documentElement = document.getDocumentElement();
// Add name space to root element as attribute
documentElement.setAttribute("xmlns:req", "http://you_name_space");