<?xml version="1.0" encoding="UTF-8" ?> <!--DTD外部引用：--> <!DOCTYPE note SYSTEM "note.dtd"> <!--外联文件可以不写申明，如果写必须要有encoding="UTF-8" SYSTEM代表系统内部调用，后面是相对路径--> <!--DTD内嵌引用 --> <!DOCTYPE note [ <!ELEMENT note (to?,from+,heading,body)> <!-- +至少一次 *一次或多次 ？0或1次 默认一次 |或者--> <!ELEMENT to (#PCDATA)> <!-- 注意， to后面一定加空格 --> <!ELEMENT from (#PCDATA)> <!ELEMENT heading (#PCDATA)> <!ELEMENT body (#PCDATA)> <!ATTLIST to copy CDATA #IMPLIED> ]> <!-- 添加属性：<!ATTLIST 元素名称 属性名称 属性类型 默认值> 常用属性： CDATA 值为字符数据 (character data) 属性必须添加 约束： REQUIRED 属性值是必需的 #IMPLIED 属性不是必需的 #FIXED value 属性值是固定的 --> <!-- 对应此约束的ＸＭＬ文件 --> <note> <to>George</to> <from>John</from> <heading>Reminder</heading> <body>Don't forget the meeting!</body> </note> --> <!-- DTD示例 --> <!DOCTYPE students[ <!ELEMENT students (student)> <!ELEMENT student (#PCDATA)> <!ELEMENT name (#PCDATA)> <!ELEMENT age (#PCDATA)> <!ELEMENT addr (#PCDATA)> ]> <!DOCTYPE book[ <!ELEMENT book (name,price,date,author)> <!ELEMENT name (#PCDATA)> <!ELEMENT price (#PCDATA)> <!ELEMENT date (#PCDATA)> <!ELEMENT author (#PCDATA)> ]> <!-- 一份XML文件中只能有一个DTD约束，不然会报错：Already seen doctype. --> <!-- 示例1 --> <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE TVSCHEDULE [ <!ELEMENT TVSCHEDULE (CHANNEL+)> <!ELEMENT CHANNEL (BANNER,DAY+)> <!ELEMENT BANNER (#PCDATA)> <!ELEMENT DAY (DATE,(HOLIDAY|PROGRAMSLOT+)+)> <!ELEMENT HOLIDAY (#PCDATA)> <!ELEMENT DATE (#PCDATA)> <!ELEMENT PROGRAMSLOT (TIME,TITLE,DESCRIPTION?)> <!ELEMENT TIME (#PCDATA)> <!ELEMENT TITLE (#PCDATA)> <!ELEMENT DESCRIPTION (#PCDATA)> <!ATTLIST TVSCHEDULE NAME CDATA #REQUIRED> <!ATTLIST CHANNEL CHAN CDATA #REQUIRED> <!ATTLIST PROGRAMSLOT VTR CDATA #IMPLIED> <!ATTLIST TITLE RATING CDATA #IMPLIED> <!ATTLIST TITLE LANGUAGE CDATA #IMPLIED> ]> <TVSCHEDULE NAME="中国电视报"> <CHANNEL CHAN="cctv-2"> <BANNER>江苏卫视</BANNER> <DAY> <DATE>2018-3-2</DATE> <PROGRAMSLOT> <TIME>20:00</TIME> <TITLE>春晚</TITLE> </PROGRAMSLOT> </DAY> </CHANNEL> </TVSCHEDULE> <!-- 示例2 --> <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE NEWSPAPER [ <!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> <!ENTITY NEWSPAPER "Vervet Logic Times"> <!-- 实体引用 --> <!ENTITY PUBLISHER "Vervet Logic Press"> <!ENTITY COPYRIGHT "Copyright 1998 Vervet Logic Press"> ]> <NEWSPAPER> <ARTICLE AUTHOR="PIKAQIU"> <HEADLINE>2018新年第一场雪</HEADLINE> <BYLINE>SEU学生会</BYLINE> <LEAD>新年报道</LEAD> <BODY>XXXXXXX</BODY> <NOTES>（宣传组报道）</NOTES> </ARTICLE> </NEWSPAPER>