xml从入门到精通之schema文件

dtd文件的作用就是约束xml文档，但是他不够牛逼，不够灵活。所以schema就孕育而生！！！

01.xsd //sechma文件的后缀是xsd

<?xml version="1.0" encoding="UTF-8"?><schema xmlns="http://www.w3.org/2001/XMLSchema"         targetNamespace="http://www.example.org/01"        xmlns:tns="http://www.example.org/01"         elementFormDefault="qualified">    <element name="user">        <complexType>            <sequence>                <element name="id" type="int"/>                <element name="username" type="string"/>                <element name="born" type="date"/>            </sequence>        </complexType>    </element></schema>

<?xml version="1.0" encoding="UTF-8"?><user xmlns="http://www.example.org/01"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xsi:schemaLocation="http://www.example.org/01">    <id>1</id>    <username>zhangsan</username>    <born>1989-12-22</born></user>

写好之后引入xml文件

另外一种引入方式

下面写几个比较常用的几个参数

02.xsd

<?xml version="1.0" encoding="UTF-8"?><schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.example.org/02"    xmlns:tns="http://www.example.org/02" elementFormDefault="qualified">    <element name="books">        <complexType>        <!-- maxOccurs表示最大出现次数 -->            <sequence maxOccurs="unbounded">                <element name="book">                    <complexType>                        <sequence minOccurs="1" maxOccurs="unbounded">                            <element name="title" type="string" />                            <element name="content" type="string" />                            <choice>                                <element name="author" type="string" />                                <element name="authors">                                    <complexType>                                        <all><!-- 每个元素只能出现一次 -->                                            <element name="author" type="string"/>                                        </all>                                    </complexType>                                </element>                            </choice>                        </sequence>                        <attribute name="id" type="int" use="required"/>                    </complexType>                </element>            </sequence>        </complexType>    </element></schema>

02.xml

<?xml version="1.0" encoding="UTF-8"?><book:books xmlns:book="http://www.example.org/02"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xsi:noNamespaceSchemaLocation="02.xsd">    <book:book id="1">        <book:title>Java in action</book:title>        <book:content>Java is good</book:content>        <book:author>Bruce</book:author>    </book:book>    <book:book id="2">        <book:title>SOA in action</book:title>        <book:content>soa is difficult</book:content>        <book:authors>            <book:author>Jike</book:author>        </book:authors>    </book:book></book:books>

这里定义book的属性，一定要写在sequence之后