JavaWeb12.2【XML：约束、DTD、Schema(XSD)】

 

 

 

 

 DTD --> XML

<!ELEMENT students (student*) > <!--*表示可以出现无限次-->
<!ELEMENT student (name,age,sex)> <!--严格属性顺序：name,age,sex-->
<!ELEMENT name (#PCDATA)>  <!--PCDATA表示字符串类型数据-->
<!ELEMENT age (#PCDATA)>
<!ELEMENT sex (#PCDATA)>
<!ATTLIST student number ID #REQUIRED> <!--student的属性number是ID，必选-->

<!--这是一个外部的dtd约束文件，即规定xml文档的书写规则-->

<?xml version="1.0" encoding="UTF-8" ?>
<!--引入本地外部dtd约束文件的声明-->
<!DOCTYPE students SYSTEM "student.dtd">

<!--内部dtd约束定义方式-->
<!--<!DOCTYPE students[
        <!ELEMENT students (student*) >
        <!ELEMENT student (name,age,sex)>
        <!ELEMENT name (#PCDATA)>
        <!ELEMENT age (#PCDATA)>
        <!ELEMENT sex (#PCDATA)>
        <!ATTLIST student number ID #REQUIRED>
]>-->

<students>
    <student number="itcast_0001">
        <name>tom</name>
        <age>9999</age>
        <sex>male</sex>
    </student>
    <student number="itcast_0002">
        <name>sam</name>
        <age>20</age>
        <sex>female</sex>
    </student>
    <!--<aaa></aaa> 不按约束写标签会变红报错-->
</students>

 

XSD --> XML

<?xml version="1.0"?>
<xsd:schema xmlns="http://www.itcast.cn/xml"
        xmlns:xsd="http://www.w3.org/2001/XMLSchema"
        targetNamespace="http://www.itcast.cn/xml" elementFormDefault="qualified">

    <xsd:element name="students" type="studentsType"/>
    <xsd:complexType name="studentsType">
        <xsd:sequence>
            <xsd:element name="student" type="studentType" minOccurs="0" maxOccurs="unbounded"/>
        </xsd:sequence>
    </xsd:complexType>
    <xsd:complexType name="studentType">
        <xsd:sequence>
            <xsd:element name="name" type="xsd:string"/>
            <xsd:element name="age" type="ageType" />
            <xsd:element name="sex" type="sexType" />
        </xsd:sequence>
        <xsd:attribute name="number" type="numberType" use="required"/>
    </xsd:complexType>
    <xsd:simpleType name="sexType">
        <xsd:restriction base="xsd:string">
            <xsd:enumeration value="male"/>
            <xsd:enumeration value="female"/>
        </xsd:restriction>
    </xsd:simpleType>
    <xsd:simpleType name="ageType">
        <xsd:restriction base="xsd:integer">
            <xsd:minInclusive value="0"/>
            <xsd:maxInclusive value="256"/>
        </xsd:restriction>
    </xsd:simpleType>
    <xsd:simpleType name="numberType">
        <xsd:restriction base="xsd:string">
            <xsd:pattern value="heima_\d{4}"/>
        </xsd:restriction>
    </xsd:simpleType>

</xsd:schema> 

<?xml version="1.0" encoding="UTF-8" ?>
<!-- 
    1.填写xml文档的根元素
    2.引入xsi前缀  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    3.引入xsd文件命名空间  xsi:schemaLocation="http://www.itcast.cn/xml  student.xsd"
    4.为每一个xsd约束声明一个前缀,作为标识  xmlns="http://www.itcast.cn/xml"
 -->
 <students   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:schemaLocation="http://www.itcast.cn/xml  student.xsd"
             xmlns="http://www.itcast.cn/xml">  <!--使用了默认的空前缀-->

     <student number="heima_0001">
         <name>tom</name>
         <age>18</age>
         <sex>male</sex>
     </student>
    <!--<student number="hehe_0001"> 报错
        <name>tom</name>
        <age>999</age> 报错
        <sex>男</sex> 报错
    </student>-->
         
 </students>


<!--
<students   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://www.itcast.cn/xml  student.xsd
                                http://www.itcast.cn/xml2  student2.xsd
                                http://www.itcast.cn/xml3  student3.xsd"
            xmlns="http://www.itcast.cn/xml"
            xmlns:b="http://www.itcast.cn/xml2">
            xmlns:c="http://www.itcast.cn/xml3">-->
<!--前缀用于区分不同xsd约束中的同名内容-->