Java 13 DocumentBuilder在解析DTD文件以验证HTML时中断

我正在开发使用DocumentBuilder解析旧HTML文件的程序，以便可以对其进行相应的处理。在此 HTML 文件中，我们有以下内容

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

以下是执行读取的代码片段：

DocumentBuilderFactory documentBuilderFactory;
DocumentBuilder documentBuilder;
documentBuilderFactory = DocumentBuilderFactory.newInstance();
documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document doc = documentBuilder.parse(htmlSource);

然后，解析失败并显示以下错误：

Error 1:    The declaration for the entity "HTML.Version" must end with '>'.
      Column Number:    3
      System Identifer: null
      toString:         org.xml.sax.SAXParseException; lineNumber: 31; columnNumber: 3; The declaration for the entity "HTML.Version" must end with '>'.
      Line Number:      31
      Public Identifer: null
      Caused By:
      The declaration for the entity "HTML.Version" must end with '>'.
      Trace Follows:
org.xml.sax.SAXParseException; lineNumber: 31; columnNumber: 3; The declaration for the entity "HTML.Version" must end with '>'.
        at java.xml/com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:204)
        at java.xml/com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(ErrorHandlerWrapper.java:178)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:400)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:327)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(XMLScanner.java:1471)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.scanEntityDecl(XMLDTDScannerImpl.java:1597)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.scanDecls(XMLDTDScannerImpl.java:2021)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.scanDTDExternalSubset(XMLDTDScannerImpl.java:299)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.dispatch(XMLDocumentScannerImpl.java:1165)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.next(XMLDocumentScannerImpl.java:1040)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:943)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605)
        at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:541)
        at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:888)
        at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:824)
        at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
        at java.xml/com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:246)
        at java.xml/com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:339)
        at com.rockwellcollins.ana.xml.XmlParser.parse(XmlParser.java:490)
        at com.rockwellcollins.ana.xml.XmlParser.parse(XmlParser.java:592)
        at com.rockwellcollins.qimt.doorsmapper.doorsmapper.HtmlParser.parseHtml(HtmlParser.java:301)
        at com.rockwellcollins.qimt.doorsmapper.doorsmapper.DoorsMapper.applicationSpecificDoIt(DoorsMapper.java:232)
        at com.rockwellcollins.application.common.ApplicationBase.doIt(ApplicationBase.java:795)
        at com.rockwellcollins.qimt.doorsmapper.doorsmapper.DoorsMapper.main(DoorsMapper.java:300)

它抱怨DTD文件的这一部分：

<!ENTITY % HTML.Version "-//W3C//DTD HTML 4.01 Transitional//EN"
  -- Typical usage:
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
            "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    ...
    </head>
    <body>
    ...
    </body>
    </html>
    The URI used as a system identifier with the public identifier allows
    the user agent to download the DTD and entity sets as needed.
    The FPI for the Strict HTML 4.01 DTD is:
        "-//W3C//DTD HTML 4.01//EN"
    This version of the strict DTD is:
        http://www.w3.org/TR/1999/REC-html401-19991224/strict.dtd
    Authors should use the Strict DTD unless they need the
    presentation control for user agents that don't (adequately)
    support style sheets.
    If you are writing a document that includes frames, use 
    the following FPI:
        "-//W3C//DTD HTML 4.01 Frameset//EN"
    This version of the frameset DTD is:
        http://www.w3.org/TR/1999/REC-html401-19991224/frameset.dtd
    Use the following (relative) URIs to refer to 
    the DTDs and entity definitions of this specification:
    "strict.dtd"
    "loose.dtd"
    "frameset.dtd"
    "HTMLlat1.ent"
    "HTMLsymbol.ent"
    "HTMLspecial.ent"
-->

从我最初的调查来看，它抱怨标签中的--评论。如果我删除这些错误，那么第一个错误就会消失并移动到下一个错误。我的问题是，为什么文档生成器无法正确读取DTD文件？

补充一点，我们无法从 HTML 文件中删除 DTD，因为提供的 HTML 是特定于 HTML 4 的，没有它，解析会因 HTML 4 格式而失败。

HTML

4.01是SGML DTD(XML是SGML的子集(，HTML不能使用XML解析器解析。您是对的，与XML相比，SGML中的注释语法允许注释在任何地方多次出现在标记声明中。例如，以下是有效的 SGML 元素声明：

<!ELEMENT e - - (#PCDATA)
  -- declaration for e --
  -- ... other comment -->

该声明还暗示了 SGML 的 XML 子集不支持(但解析 HTML 需要(的功能之一，即标记推断(标记省略(。元素名称后面的- O序列e表示e允许省略结束元素标记(字母 O 中的"O"(，但不允许省略起始元素("-"连字符减号(。XML 不支持的其他所需功能是 SGML/HTML 样式的空元素，例如 img(没有结束元素标记(和属性最小化(如 <div hidden> 所示(。

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