使用Stax进行DTD解析

时间:2013-10-07 14:24:31

标签: java dtd stax html4

我想解析声明HTML 4.01 Doctype的xml文件。

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

我使用Stax和XMLResolver来加载本地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;
        }
    }

我从(w3c web site)检索了dtd。但我必须更改此文件以删除节点中的所有注释,如下所示:

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

 <!ENTITY % ContentType "CDATA">

但即使经过这些修改,我仍然有这个错误:

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)
在dtd文件中的

,第184行是:

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

任何想法?

由于

1 个答案:

答案 0 :(得分:2)

HTML是一种SGML语言,因此它有一个SGML DTD。您可以在此处找到有关SGML的更多信息:http://validator.w3.org/docs/sgml.html

SGML与XML略有不同,因此XML解析器无法解析它也就不足为奇了。

主要的例子是:

实体声明中的注释(用双连字符分隔: - 这是注释 - )在SGML DTD中是允许的,而不在XML DTD上。

如需更多信息,请点击http://www.w3.org/TR/NOTE-sgml-xml-971215#null

尽管如此,您无法通过创建自己的XMLResolver

来禁用特定DTD的DTD解析
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("");
        }
        ...
    }
});

对于html解析器,请将http://jtidy.sourceforge.net/http://jsoup.org/视为解决方案