DTD parsing with Stax

2018-06-12 04:40:33

i want to parse xml files which declare a HTML 4.01 Doctype.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
[...]
</html>

I using Stax and an XMLResolver for load local dtd

XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
xmlInputFactory.setXMLResolver(new LocalXmlResolver());
xmlOutputFactory = XMLOutputFactory.newInstance();
xmlOutputFactory.createXMLEventWriter(...)


private static final Map<String, String> DTDS = new HashMap<String, String>(){{
    // XHTML 1.0 DTDs
    put("-//W3C//DTD XHTML 1.0 Strict//EN", "xhtml1-strict.dtd");
    put("-//W3C//DTD XHTML 1.0 Transitional//EN", "xhtml1-transitional.dtd");
    put("-//W3C//DTD XHTML 1.0 Frameset//EN", "xhtml1-frameset.dtd");

    put("-//W3C//DTD HTML 4.01//EN", "strict.dtd");
    put("-//W3C//DTD HTML 4.01 Transitional//EN", "loose.dtd");
    put("-//W3C//DTD HTML 4.01 Frameset//EN", "frameset.dtd");
}};

private static final class LocalXmlResolver implements XMLResolver {

        @Override
        public Object resolveEntity(String publicID, String systemID, String baseURI, String namespace) throws XMLStreamException {
            Object result = null;

            String path = XHTML_DTD_PATH + DTDS.get(publicID);

            if (StringUtils.isNotBlank(path)) {
                result = getClass().getClassLoader().getResourceAsStream(path);
            }
            return result;
        }
    }

i retrieved dtd from the (w3c web site). But i had to change this file to remove all comments in nodes like below :

 <!ENTITY % ContentType "CDATA"
    -- media type, as per [RFC2045]
    --> 

 <!ENTITY % ContentType "CDATA">

But even after these modifications, i have still this error :

javax.xml.stream.XMLStreamException: ParseError at [row,col]:[184,11]
Message: The element type is required in the element type declaration.
    [...]
Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[184,11]
Message: The element type is required in the element type declaration.
    at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLStreamReaderImpl.java:598)
    at com.sun.xml.internal.stream.XMLEventReaderImpl.nextEvent(XMLEventReaderImpl.java:83)

in the dtd file, the line 184 is :

<!ELEMENT (%fontstyle;|%phrase;) - - (%inline;)* >

any idea ?

Thanks

HTML is an SGML language, so it has an SGML DTD. You can find some more information about SGML here: http://validator.w3.org/docs/sgml.html

SGML is a bit different than XML, so it's no wonder that an XML parser cannot parse it.

The main example is:

comments inside entity declarations (delimited with double hyphens: --this is a comment--) is allowed in SGML DTD whereas is not on XML DTD.

For more difference please follow http://www.w3.org/TR/NOTE-sgml-xml-971215#null

Nevertheless you can't disable DTD parsing for specific DTD by creation your own XMLResolver

xmlInput = XMLInputFactory.newInstance();
xmlInput.setXMLResolver(new XMLResolver() {
    @Override
    public Object resolveEntity(String publicID, String systemID, String baseURI, String namespace) throws XMLStreamException {
        ...
        // Disable dtd validation
        if ("The public id you except".equals(publicId)) {
            return IOUtils.toInputStream("");
        }
        ...
    }
});

For html parser consider http://jtidy.sourceforge.net/ or http://jsoup.org/ as solution

链接地址: http://www.djcxy.com/p/34902.html

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