java - DOM XML Public Doctype 未出现在结果 xml 文件中

Question

我已经编写了生成 XML 文件的代码。我一直坚持为 XML 定义文档类型，因为它应该是公共(public)的。我能够成功获取 SYSTEM 文档类型，但不知何故无法获取用 XML 编写的公共(public)文档类型。下面的 SYSTEM doctype 代码可以正常工作，但 PUBLIC doctype 的相同代码段不起作用:

String xmldestpath = "C:/failed/tester.xml";
        doctype2 = CreateDoctypeString();

        StreamResult result =  new StreamResult(new File(xmldestpath ));
          try {
              transformer = transformerFactory.newTransformer();
              transformer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM,"TEST");
              transformer.transform(source, result);
    //        logger.debug("COMPLETED Copying xml files /....!!");            

            System.out.println("COMPLETED Copying xml files to bulk import....!!");

不工作的片段。它没有给出错误，但结果 xml 中没有出现文档类型:

 String xmldestpath = "C:/failed/tester.xml";
    doctype2 = CreateDoctypeString();

    StreamResult result =  new StreamResult(new File(xmldestpath ));
      try {
          transformer = transformerFactory.newTransformer();
          transformer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC,"TEST");
          transformer.transform(source, result);
//        //logger.debug("COMPLETED Copying xml files /....!!");              

        System.out.println("COMPLETED Copying xml files to bulk import....!!");

Answer 1

如果您知道您需要/想要PUBLIC，也许您应该知道如果没有系统文字，公共(public)文字就不可能存在。

XML specification显示:

ExternalID  ::=  'SYSTEM' S SystemLiteral
                 | 'PUBLIC' S PubidLiteral S SystemLiteral

因此应该很容易得出结论，您需要指定两者才能使其正常工作，如MCVE所示:

TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, "TEST1");
transformer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, "TEST2");
transformer.transform(new StreamSource(new StringReader("<Root></Root>")),
                      new StreamResult(System.out));

输出

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE Root PUBLIC "TEST1" "TEST2">
<Root/>