xml 入门 dtd

xml dtd的格式：

<?xml version="1.0" encoding="UTF-8"?> <!ELEMENT classroom (className,grade,students)> <!ATTLIST classroom id ID #REQUIRED> <!ELEMENT className (#PCDATA)> <!ELEMENT grade (#PCDATA)> <!ELEMENT students (student+)> <!ELEMENT student (id,name,age)> <!ELEMENT id (#PCDATA)> <!ELEMENT name (#PCDATA)> <!ELEMENT age (#PCDATA)>
相应的xml文件：

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE classroom SYSTEM "classroom.dtd"> <!--<!DOCTYPE classroom PUBLIC "http://www.zizhu.com/classroom">--> <classroom id="p1"> <className>2010计算机应用技术</className> <grade>2010</grade> <students> <student> <id>11</id> <name>zizhu8</name> <age>20</age> </student> <student> <id>12</id> <name>zizhu3</name> <age>20</age> </student> </students> </classroom>