import com.sun.xml.internal.ws.util.FastInfosetUtil; //导入依赖的package包/类
public static XMLStreamReader createSourceReader(Source source, boolean rejectDTDs, String charsetName) {
    try {
        if (source instanceof StreamSource) {
            StreamSource streamSource = (StreamSource) source;
            InputStream is = streamSource.getInputStream();

            if (is != null) {
                // Wrap input stream in Reader if charset is specified
                if (charsetName != null) {
                    return XMLStreamReaderFactory.create(
                        source.getSystemId(), new InputStreamReader(is, charsetName), rejectDTDs);
                }
                else {
                    return XMLStreamReaderFactory.create(
                        source.getSystemId(), is, rejectDTDs);
                }
            }
            else {
                Reader reader = streamSource.getReader();
                if (reader != null) {
                    return XMLStreamReaderFactory.create(
                        source.getSystemId(), reader, rejectDTDs);
                }
                else {
                    return XMLStreamReaderFactory.create(
                        source.getSystemId(), new URL(source.getSystemId()).openStream(), rejectDTDs );
                }
            }
        }
        else if (source.getClass() == fastInfosetSourceClass) {
            return FastInfosetUtil.createFIStreamReader((InputStream)
                fastInfosetSource_getInputStream.invoke(source));
        }
        else if (source instanceof DOMSource) {
            DOMStreamReader dsr =  new DOMStreamReader();
            dsr.setCurrentNode(((DOMSource) source).getNode());
            return dsr;
        }
        else if (source instanceof SAXSource) {
            // TODO: need SAX to StAX adapter here -- Use transformer for now
            Transformer tx =  XmlUtil.newTransformer();
            DOMResult domResult = new DOMResult();
            tx.transform(source, domResult);
            return createSourceReader(
                new DOMSource(domResult.getNode()),
                rejectDTDs);
        }
        else {
            throw new XMLReaderException("sourceReader.invalidSource",
                    source.getClass().getName());
        }
    }
    catch (Exception e) {
        throw new XMLReaderException(e);
    }
}