DTD与XSD的一个范例

一个xml的格式如下，

<?xml version="1.0"?>
<!-- 本文档根元素为gridbag, 其中验证文档为gridbag.dtd -->
<!DOCTYPE gridbag SYSTEM "gridbag.dtd">
<gridbag>
	<row>
		<cell anchor="EAST">
			<bean>
				<class>javax.swing.JLabel</class>
				<property>
					<name>text</name>
					<value><string>Face:</string></value>
				</property>
			</bean>
		</cell>
		<cell fill="HORIZONTAL" weightx="100">
			<bean id="face">
				<class>javax.swing.JComboBox</class>
			</bean>
		</cell>
		<cell gridheight="4" fill="BOTH" weightx="100" weighty="100">
			<bean id="sample">
				<class>javax.swing.JTextArea</class>
				<property>
					<name>text</name>
					<value><string>The quick brown fox jumps over the lazy dog</string></value>
				</property>
				<property>
					<name>editable</name>
					<value><bolean>false</bolean></value>
				</property>
				<property>
					<name>lineWrap</name>
					<value><boolean>true</boolean></value>
				</property>
				<property>
					<name>border</name>
					<value>
						<bean>
							<class>javax.swing.border.EtchedBorder</class>
						</bean>
					</value>
				</property>
			</bean>
		</cell>
	</row>
	<row>
		<cell gridwidth="2" weighty="100">
			<bean id="bold">
				<class>javax.swing.JCheckBox</class>
				<property>
					<name>text</name>
					<value><string>Bold</string></value>
				</property>
			</bean>
		</cell>
	</row>
	<row>
		<cell gridwidth="2" weighty="100">
			<bean id="italic">
				<class>javax.swing.JCheckBox</class>
				<property>
					<name>text</name>
					<value><string>Italic</string></value>
				</property>
			</bean>
		</cell>
	</row>
</gridbag>

，对就在的dtd文件格式：

<!ELEMENT gridbag (row)*>  <!--根元素是gridbag,可以多个子元素row-->
<!ELEMENT row(cell)*>  <!--row下面可以有多个cell子元素 -->
<!ELEMENT cell(bean)> <!--cell元素下只有一个bean元素-->
<!ATTLIST cell gridx CDATA #IMPLIED>  <!--cell有gridx属性，类型为任意文本,如果有特殊字符用相应的替代字符代替（用于属性中），可选-->
<!ATTLIST cell gridy CDATA #IMPLIED> 
<!ATTLIST cell gridwidth CDATA "1"> <!--gridwidhth属性默认为1-->
<!ATTLIST cell gridheight CDATA "1">
<!ATTLIST cell weightx CDATA "0">
<!ATTLIST cell weighty CDATA "0">
<!ATTLIST cell fill (NODE|BOTH|HORIZONTAL|VERTICAL) "NONE"> <!--fill属性有几个可选值，默认为NONE-->
<!ATTLIST cell anchor (CENTER|NORTH|NORTHEAST|EAST|SOUTHEAST|SOUTH|SOUTHWEST|WEST|NORTHWEST) “CENTER”>
<!ATTLIST cell ipdx CDATA "0">
<!ATTLIST cell ipady CDATA "0">

<!ELEMENT bean (class, property*)> <!--bean子元素有一个class子元素，多个property子元素-->
<!ATTLIST bean id ID #IMPLIED> <!--bean的id属性是ID类型，也就是唯一性 -->

<!ELEMENT class (#PCDATA)> <!--class元素下面可以只包含文本也可以包含子元素，类似于ANY(用于元素中)-->
<!ELEMENT property (name, value)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT value (int|string|boolean|bean)>
<!ELEMENT int (#PCDATA)>
<!ELEMENT string (#PCDATA)>
<!ELEMENT boolean (#PCDATA)>

XSD文件格式如下

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
	<xsd:element name="gridbag" type="GridBagType"/><!--根元素-->
	
	<xsd:element name="bean" type="BeanType"/>
	
	<xsd:complexType name="GridBagType">
		<xsd:sequence>
			<xsd:element name="row" type="RowType" minOccurs="0" maxOccurs="unbounded"/>
		</xsd:sequence>
	</xsd:complexType>
	
	<xsd:complexType name="RowType">
		<xsd:sequence>
			<xsd:element name="cell" type="CellType" minOccurs="0" maxOccurs="unbounded"/>
		</xsd:sequence>
	</xsd:complexType>
	
	<xsd:complexType name="CellType">
		<xsd:sequence>
			<xsd:element ref="bean"></xsd:element>
		</xsd:sequence>
		<xsd:attribute name="gridx" type="xsd:int" use="optional"/>
		<xsd:attribute name="gridy" type="xsd:int" use="optional"></xsd:attribute>
		<xsd:attribute name="gridwidth" type="xsd:int" use="optional" default="1"></xsd:attribute>
		<xsd:attribute name="gridheight" type="xsd:int" use="optional" default="1"/>
		<xsd:attribute name="weightx" type="xsd:int" use="optional" default="0"/>
		<xsd:attribute name="weighty" type="xsd:int" use="optional" default="0"/>
		<xsd:attribute name="fill" use="optional" default="NONE">
			<xsd:simpleType>
				<xsd:retriction base="xsd:string">
					<xsd:enumeration value="NONE"/>
					<xsd:enumeration value="BOTH"/>
					<xsd:enumeration value="HORIZONTAL"/>
					<xsd:enumeration value="VERTICAL"></xsd:enumeration>
				</xsd:retriction>
			</xsd:simpleType>
		</xsd:attribute>
		<xsd:attribute name="anchor" use="optional" default="CENTER">
			<xsd:simpleType>
				<xsd:retriction base="xsd:string">
					<xsd:enumeration value="CENTER"></xsd:enumeration>
					<xsd:enumeration value="NORTH"/>
					<!-- 下面的类同 -->
				</xsd:retriction>
			</xsd:simpleType>
		</xsd:attribute>
		<xsd:attribute name="ipady" type="xsd:int" use="optional" default="0"></xsd:attribute>
		<xsd:attribute name="ipadx" type="xsd:int" use="optional" default="0"/>
	</xsd:complexType>
	
	<xsd:complexType name="BeanType">
		<xsd:sequence>
			<xsd:element name="class" type="xsd:string"/>
			<xsd:element name="property" type="PropertyType" minOccurs="0" maxOccurs="unbounded"/>
		</xsd:sequence>
		<xsd:attibute name="id" type="xsd:ID" use="optional"></xsd:attibute>
	</xsd:complexType>
	
	<xsd:complexType name="PropertyType">
		<xsd:sequence>
			<xsd:element name="name" tyype="xsd:string"/>
			<xsd:element name="value" type="ValueType"/>
		</xsd:sequence>
	</xsd:complexType>
	
	<xsd:complexType>
		<xsd:choice>
			<xsd:element ref="bean"/>
			<xsd:element name="int" type="xsd:int"/>
			<xsd:element name="string" type="xsd:string"/>
			<xsd:element name="boolean" type="xsd:boolean"/>
		</xsd:choice>
	</xsd:complexType>
</xsd:schema>

DTD比XSD简单，功能上也相对较弱