XML文件基础，DTD校验文件编写，Schema文件的简单使用

dtd

<!--
        <!ELEMENT 元素(子元素,...)>
    -->
    <!ELEMENT students (student+,cat*) >
    <!ELEMENT student (name,age,sex,birth,phone*,email?,student?) ><!-- 注意元素的顺序 -->
    <!ELEMENT email EMPTY><!-- 元素里面不能包含内容 -->
    <!ELEMENT phone (#PCDATA)>
    <!ATTLIST sex value (男|女|保密) "男"><!-- 属性值可以使用枚举类型 -->
    <!-- 
        定义student元素的stuNo属性 
        ID类型: 保证唯一性(必须由数字和字母组成)
        CDATA类型: 指定是字符串类型
        
        #REQUIRED 属性值是必须
        #IMPLIED  属性值是可选
    -->
    <!ATTLIST student stuNO ID #IMPLIED>
    <!ATTLIST email value CDATA #IMPLIED>

xml

<?xml version="1.0" encoding="UTF-8" ?><!-- xml文件的声明 -->
<!DOCTYPE students SYSTEM "student.dtd"><!-- 引用外部的dtd校验文件 -->
<students>
    <student stuNO="STU0001">
        <name>关羽</name>
        <age>20</age>
        <sex>男</sex>
        <birth>1988-10-29</birth>
        <email value="guanyu@qq.com" />
        <student stuNO="SUT11001">
            <name>关羽</name>
            <age>20</age>
            <sex value="女">男</sex>
            <birth>1988-10-29</birth>
            <email value="guanyu@qq.com" />
        </student>
    </student>

    <student stuNO="STU0002">
        <name>李四</name>
        <age>20</age>
        <sex>男</sex>
        <birth>1988-10-29</birth>
        <phone>123332</phone>
        <email value="guanyu@qq.com" ></email>
    </student>

    <student stuNO="STU0003">
        <name>貂蝉</name>
        <age>20</age>
        <sex>女</sex>
        <birth>1988-10-29</birth>
        <phone>123332</phone>
        <phone>123332</phone>
        <!-- <email value="guanyu@qq.com" >fdfj</email> -->
    </student>

    <cat>
        <sex>母</sex>
        <age>3</age>
        <name>喵喵</name>
    </cat>
    <cat>
        <sex>母</sex>
        <age>3</age>
        <name>喵喵</name>
    </cat>
</students>

schema

<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    targetNamespace="abc" xmlns="abc" elementFormDefault="qualified">
    <!-- XML Schema 缩写 当elementFormDefault="qualified" 时，所有全局元素的子元素将被以缺省方式放到目标命名空间，连同全局元素或者类型一起； 
        而当elementFormDefault="unqualified" 时，所有全局元素的子元素将被以缺省方式放到无名命名空间。而属性的命名空间类似地由attributeFormDefault="？"来指明。 
        需要明白的是，elementFormDefault="？" 是有作用域的，并且是被继承的，除非在子定义中覆盖父定义。 -->
    <xsd:element name="note">
        
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="to">
                    <xsd:complexType mixed="true"><!-- 混合 -->
                        <xsd:sequence minOccurs="1" maxOccurs="unbounded">
                            <xsd:element name="content" type="xsd:string" />
                        </xsd:sequence>
                        <xsd:attribute name="two" type="xsd:string" use="required" />
                    </xsd:complexType>
                </xsd:element>
                <xsd:element name="from" type="xsd:string" />
                <xsd:element name="heading" type="xsd:string" />
                <xsd:element name="body" type="xsd:string" />
                <xsd:element name="age" type="xsd:integer" />
                <xsd:element name="birth" type="xsd:date" />
                <xsd:element name="sex">
                    <xsd:simpleType>
                        <xsd:restriction base="xsd:string">
                            <xsd:enumeration value="男" />
                            <xsd:enumeration value="女" />
                            <xsd:enumeration value="人妖" />
                        </xsd:restriction>
                    </xsd:simpleType>
                </xsd:element>
                <xsd:element name="weight" type="xsd:decimal" />
            </xsd:sequence>
            <xsd:attribute name="one" type="xsd:string" use="required" />
        </xsd:complexType>
    </xsd:element>
</xsd:schema>

xml

<?xml version="1.0"  encoding="UTF-8" ?>
<note xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns="abc"
      xsi:schemaLocation="abc note.xsd" one="属于note">
      
    <to two="to的属性">
        <content>fdsf</content>
        <content>fdsf</content>
        <content>fsdf</content>
    </to>
    <from>John</from>
    <heading>Reminder</heading>
    <body>Don't forget the meeting!</body>
    <age>20</age>
    <birth>1988-10-23</birth>
    <sex>人妖</sex>
    <weight>75</weight>
</note>