DTD(Document Type Definition) 文档类型定义
DEMO
demo.dtd
<?xml version="1.0" encoding="UTF-8"?>
<!ELEMENT NEWSPAPER (ARTICLE)+>
<!ELEMENT ARTICLE (HEADLINE,BYLINE,LEAD,BODY,NOTES)>
<!ELEMENT HEADLINE (#PCDATA)>
<!ELEMENT BYLINE (#PCDATA)>
<!ELEMENT LEAD (#PCDATA)>
<!ELEMENT BODY (#PCDATA)>
<!ELEMENT NOTES (#PCDATA)>
<!ATTLIST ARTICLE AUTHOR CDATA #REQUIRED>
<!ATTLIST ARTICLE EDITOR CDATA #IMPLIED>
<!ATTLIST ARTICLE DATE CDATA #IMPLIED>
<!ATTLIST ARTICLE EDITION CDATA #IMPLIED>
demo.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE NEWSPAPER SYSTEM "demo.dtd">
<NEWSPAPER>
<ARTICLE AUTHOR="" EDITOR="" DATE="" EDITION="">
<HEADLINE></HEADLINE>
<BYLINE></BYLINE>
<LEAD></LEAD>
<BODY></BODY>
<NOTES></NOTES>
</ARTICLE>
</NEWSPAPER>
"SYSTEM/PUBLIC"这两个参数只用其一。SYSTEM是指文档使用的私有DTD文件的网址,而PUBLIC则指文档调用一个公用的DTD文件的网址。
<xx attribute="元素">文本/内容</xx>