在使用流分析器（SJSXP）进行验证之前，尝试从XML中剥离名称空间

Question

I'm trying to ignore the namespaces provided in the root element of an XML file, in order to validate against an external schema. Unfortunately, I cannot change some of the items, as this is a heavily intertwined legacy system.

I've read (here on SO) that I should be able to use filters around the input XML, but it doesn't seem to work and feel like I'm missing something. When I run the validation, I get the following error message:

org.xml.sax.SAXParseException: cvc-elt.1: Cannot find the declaration of element 'MY_ROOT_ELEMENT'.

Here's the beginning of the XML file with the namespace info:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<MY_ROOT_ELEMENT xmlns="http://www.mycompany.net/somename" 
  schemaVersion="2.0.0" 
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.mycompany.net/somename 
                      myschema.xsd">
    ...
</MY_ROOT_ELEMENT>

Here's the accompanying beginning of the schema where MY_ROOT_ELEMENT is defined:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
  elementFormDefault="qualified" 
  attributeFormDefault="unqualified">
    <xs:element name="MY_ROOT_ELEMENT" type="MY_ROOT_ELEMENT"/>

The StreamReaderDelegate which is used to ignore the namespace:

private static final class NoNamespaceStreamReaderDelegate extends StreamReaderDelegate {
    NoNamespaceStreamReaderDelegate(XMLStreamReader reader) {
        super(reader);
    }

    @Override
    public NamespaceContext getNamespaceContext() {
        return super.getNamespaceContext();
    }

    @Override
    public int getNamespaceCount() {
        return 1;
    }

    @Override
    public String getNamespacePrefix(int index) {
        if (index == 0) {
            return "xsi";
        }

        throw new NullPointerException();
    }

    @Override
    public String getNamespaceURI() {
        return null;
    }

    @Override
    public String getNamespaceURI(String prefix) {
        if ("xsi".equals(prefix)) {
            return XMLConstants.W3C_XML_SCHEMA_INSTANCE_NS_URI;
        }
        return null;
    }

    @Override
    public String getNamespaceURI(int index) {
        if (index == 0) {
            return XMLConstants.W3C_XML_SCHEMA_INSTANCE_NS_URI;
        }
        return null;
    }
}

And lastly, how the validation is called:

// reads from the classpath
XMLStreamReader reader = createReaderFromSource();
SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
Schema schema = sf.newSchema(inputSource.getSchema());
Source readerSource = new StAXSource(new NoNamespaceStreamReaderDelegate(reader));

Validator validator = schema.newValidator();
validator.validate(readerSource);

Answer 1

Posting this for posterity's sake.

Seems like the answer is to set the "IS_NAMESPACE_AWARE" property on the XMLInputFactory to false, and then use the StreamReaderDelegate to make sure the xsi:schemaLocation is ignored. Many wrapper libraries make this part of their API, but for the default StAX implementation , you need to set the property.

Once I declared the following, and implemented the Delegate, everything worked like a charm.

XMLInputFactory factory = XMLInputFactory.newInstance();
factory.setProperty(XMLInputFactory.IS_NAMESPACE_AWARE, Boolean.TRUE);