需要外部 DTD 标记声明 [重复]答案

【问题标题】：External DTD markup declaration expected [duplicate]需要外部 DTD 标记声明 [重复]
【发布时间】：2020-12-01 08:19:18
【问题描述】：

我在添加外部 DTD 验证时遇到了 XML 验证问题。这正常工作：

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE booklist [
<!ELEMENT booklist (book)*>
<!ELEMENT book (author,title,published?)>
<!ELEMENT author (firstname,lastname)>
<!ELEMENT firstname (#PCDATA)>
<!ELEMENT lastname (#PCDATA)>
<!ELEMENT title (#PCDATA)>
<!ELEMENT published (#PCDATA)>
<!ATTLIST book genre (Science|Fiction) #REQUIRED>
<!ATTLIST book format (Paperback|Hardcover) "Paperback">
]>
<booklist>
  <book genre="Fiction" format="Paperback">
    <author>
      <firstname>Name</firstname>
      <lastname>Surname</lastname>
    </author>
    <title>Sample</title>
    <published>2020</published>
  </book>
</booklist>

当我尝试添加外部 dtd 声明时，XML 复制编辑器输出错误

第 1 行第 3 列的致命错误：需要标记声明

XML

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE booklist SYSTEM "booklist.dtd">
<booklist>
  <book genre="Fiction" format="Paperback">
    <author>
      <firstname>Name</firstname>
      <lastname>Surname</lastname>
    </author>
    <title>Sample</title>
    <published>2020</published>
  </book>
</booklist>

DTD

<!DOCTYPE booklist [
<!ELEMENT booklist (book)*>
<!ELEMENT book (author,title,published?)>
<!ELEMENT author (firstname,lastname)>
<!ELEMENT firstname (#PCDATA)>
<!ELEMENT lastname (#PCDATA)>
<!ELEMENT title (#PCDATA)>
<!ELEMENT published (#PCDATA)>
<!ATTLIST book genre (Science|Fiction) #REQUIRED>
<!ATTLIST book format (Paperback|Hardcover) "Paperback">
]>

我做错了什么？

【问题讨论】：

标签： xml dtd xml-validation

【解决方案1】：

删除外部子集的 DOCTYPE 包装器：

外部 DTD

<!ELEMENT booklist (book)*>
<!ELEMENT book (author,title,published?)>
<!ELEMENT author (firstname,lastname)>
<!ELEMENT firstname (#PCDATA)>
<!ELEMENT lastname (#PCDATA)>
<!ELEMENT title (#PCDATA)>
<!ELEMENT published (#PCDATA)>
<!ATTLIST book genre (Science|Fiction) #REQUIRED>
<!ATTLIST book format (Paperback|Hardcover) "Paperback">

【讨论】：