How to apply validation of local DTD file to xml file in java?

Question

I need to parse a bunch of incoming XML documents but it does not contain DTD declaration. Currently I am parsing xml documents using SAX Parser but without DTD validation. Now I want to apply DTD validation. DTD is created by myself. How can I validate an XML file using DTD created by myself (SAX parser) ? I found some tutorials using Transformer but all for DOM Parser.

How to parse XML file using SAX Parser and also applying DTD validation. Any help....

Answer 1

Below is a sample that I believe could help to do what you want:

private void loadXML(Reader reader) throws ParserConfigurationException, SAXException {
    SAXParserFactory parserFactory = SAXParserFactory.newInstance();
    parserFactory.setValidating(true);
    SAXParser parser = parserFactory.newSAXParser();
    parser.parse(new InputSource(reader), new MyHandler());
}

private static class MyHandler
        extends DefaultHandler {

    private static final String PREFS_DTD_URI = "http://www.example.com/dtd/document.dtd";

    public InputSource resolveEntity(String publicId, String systemId) throws SAXException {
        if (systemId.equals(PREFS_DTD_URI)) {
            InputSource is = new InputSource(new StringReader(PREFS_DTD));  // PREFS_DTD is a string containing actual DTD, any other Reader could be here
            is.setSystemId(PREFS_DTD_URI);
            return is;
        }
        // else use the default behaviour
        return null;
    }
}