dtd讲解

dtd讲解

classroom.dtd文件：<?xml version="1.0" encoding="UTF-8"?>
<!ELEMENT classroom (claName,grade,students)>
<!ATTLIST classroom id ID #REQUIRED>
<!ELEMENT claName (#PCDATA)>
<!ELEMENT grade (#PCDATA)>
<!ELEMENT students (student+)>
<!ELEMENT student (id,stuName,age)>
<!ELEMENT id (#PCDATA)>
<!ELEMENT stuName (#PCDATA)>
<!ELEMENT age (#PCDATA)>

classroom.xml文件：<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE classroom SYSTEM "classroom.dtd">
<classroom id="c1">
 <claName>10计算机应用技术</claName>
 <grade>2010</grade>
 <students>
  <student>
   <id>1</id>
   <stuName>zhangsan</stuName>
   <age>12</age>
  </student>
  <student>
   <id>2</id>
   <stuName>lisi</stuName>
   <age>122</age>
  </student>
 </students>
</classroom>