DTD文档类型定义简单事例

<?xml version="1.0" encoding="UTF-8"?>
<!ELEMENT address (name,street,city,state,postal-code)>
<!ELEMENT name (title?,first-name,last-name)>
<!ELEMENT title (#PCDATA)>
<!ELEMENT first-name (#PCDATA)>
<!ELEMENT last-name (#PCDATA)>
<!ELEMENT street (#PCDATA)>
<!ELEMENT city (#PCDATA)>
<!ELEMENT state (#PCDATA)>
<!ELEMENT postal-code (#PCDATA)>

<!ELEMENT addressbook (address+)>
<!ELEMENT private-addresses (address*)>

引用DTD

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE address SYSTEM "C:\Users\eping\Documents\xmlStudy\xmlDemo.dtd">
<address>
    <name>
        <first-name/>
        <last-name/>
    </name>
    <street/>
    <city/>
    <state/>
    <postal-code/>
</address>