一、实体bean的定义 回顾一下我们需要定义的4个标签

• 定义注册中心标签：

<xmen:registry name="registry" regProtocol="zookeeper" address="127.0.0.1:2181" connectTimeout="2000"/>

• 定义服务协议标签

<xmen:protocol name="xmen" port="20000" />

• 定义服务提供标签：

<xmen:service interface="xxx.xxx.xxx.service" class="xxx" port="8000"/>或者
<xmen:service interface="xxx.xxx.xxx.service" ref="xxx" port="8000"/>

• 定义服务引用标签：

<xmen:referer id="xxxService" interface="xxx.xxx.xxx.service"/>

UML图设计如下

• RegistyConfig、ServiceConfig、RefererConfig分别继承自抽象类AbstractConfig，并分别定义了三个标签的相关属性。ServiceConfigBean、RefererConfigBean用于实现spring的相关接口，达到对配置文件中bean进行处理的目的。

二、定义xsd文件（xmen.xsd）

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns="http://www.solid4j.com/schema/xmen" xmlns:xsd="http://www.w3.org/2001/XMLSchema"xmlns:tool="http://www.springframework.org/schema/tool" xmlns:beans="http://www.springframework.org/schema/beans"targetNamespace="http://www.solid4j.com/schema/xmen"><xsd:import namespace="http://www.w3.org/XML/1998/namespace" /><xsd:import namespace="http://www.springframework.org/schema/tool" /><xsd:import namespace="http://www.springframework.org/schema/beans" /><xsd:complexType name="abstractConfig"><xsd:anyAttribute /></xsd:complexType><xsd:complexType name="abstractRegistryConfig"><xsd:complexContent><xsd:extension base="abstractConfig"><xsd:attribute name="id" type="xsd:ID" /><xsd:attribute name="name" type="xsd:string" use="optional"><xsd:annotation><xsd:documentation><![CDATA[ 注册名称. ]]></xsd:documentation></xsd:annotation></xsd:attribute><xsd:attribute name="regProtocol" type="xsd:string"use="optional"><xsd:annotation><xsd:documentation><![CDATA[ 注册协议. ]]></xsd:documentation></xsd:annotation></xsd:attribute><xsd:attribute name="address" type="xsd:string" use="optional"><xsd:annotation><xsd:documentation><![CDATA[ 注册中心地址. ]]></xsd:documentation></xsd:annotation></xsd:attribute><xsd:attribute name="connectTimeout" type="xsd:integer"use="optional"><xsd:annotation><xsd:documentation><![CDATA[ 注册中心连接超时时间(毫秒). ]]></xsd:documentation></xsd:annotation></xsd:attribute></xsd:extension></xsd:complexContent></xsd:complexType><xsd:complexType name="abstractProtocolConfig"><xsd:complexContent><xsd:extension base="abstractConfig"><xsd:attribute name="id" type="xsd:ID" /><xsd:attribute name="name" type="xsd:string" use="optional"><xsd:annotation><xsd:documentation><![CDATA[ 协议名称. ]]></xsd:documentation></xsd:annotation></xsd:attribute><xsd:attribute name="port" type="xsd:integer" use="optional"><xsd:annotation><xsd:documentation><![CDATA[ 服务端口 ]]></xsd:documentation></xsd:annotation></xsd:attribute></xsd:extension></xsd:complexContent></xsd:complexType><xsd:complexType name="abstractServiceConfig"><xsd:complexContent><xsd:extension base="abstractConfig"><xsd:attribute name="id" type="xsd:ID" /><xsd:attribute name="interface" type="xsd:token"><xsd:annotation><xsd:documentation><![CDATA[ 定义接口，在注册中心中注册 ]]></xsd:documentation><xsd:appinfo><tool:annotation><tool:expected-type type="java.lang.Class" /></tool:annotation></xsd:appinfo></xsd:annotation></xsd:attribute><xsd:attribute name="ref" type="xsd:string" use="optional"><xsd:annotation><xsd:documentation><![CDATA[ 接口实现 ]]></xsd:documentation></xsd:annotation></xsd:attribute><xsd:attribute name="class" type="xsd:string" use="optional"><xsd:annotation><xsd:documentation><![CDATA[ 接口实现 ]]></xsd:documentation></xsd:annotation></xsd:attribute></xsd:extension></xsd:complexContent></xsd:complexType><xsd:complexType name="abstractRefererConfig"><xsd:complexContent><xsd:extension base="abstractConfig"><xsd:attribute name="id" type="xsd:ID" /><xsd:attribute name="interface" type="xsd:token" use="required"><xsd:annotation><xsd:documentation><![CDATA[ 调用的接口 ]]></xsd:documentation><xsd:appinfo><tool:annotation><tool:expected-type type="java.lang.Class" /></tool:annotation></xsd:appinfo></xsd:annotation></xsd:attribute></xsd:extension></xsd:complexContent></xsd:complexType><xsd:element name="registry" type="abstractRegistryConfig"><xsd:annotation><xsd:documentation><![CDATA[ 注册中心配置 ]]></xsd:documentation></xsd:annotation></xsd:element><xsd:element name="protocol" type="abstractProtocolConfig"><xsd:annotation><xsd:documentation><![CDATA[ 服务协议 ]]></xsd:documentation></xsd:annotation></xsd:element><xsd:element name="service" type="abstractServiceConfig"><xsd:annotation><xsd:documentation><![CDATA[ 服务配置 ]]></xsd:documentation></xsd:annotation></xsd:element><xsd:element name="referer" type="abstractRefererConfig"><xsd:annotation><xsd:documentation><![CDATA[ 引用服务配置 ]]></xsd:documentation></xsd:annotation></xsd:element>
</xsd:schema>

三、定义handler处理文件（spring.schemas和spring.handlers）

http\://www.solid4j.com/schema/xmen.xsd=META-INF/xmen.xsdhttp\://www.solid4j.com/schema/xmen=com.solid4j.xmen.config.spring.handler.XmenNamespaceHandler

四、编写具体的Handler类

public class XmenNamespaceHandler extends NamespaceHandlerSupport {@Overridepublic void init() {registerBeanDefinitionParser("registry", new XmenBeanDefinitionParser(RegistryConfig.class, true));registerBeanDefinitionParser("protocol", new XmenBeanDefinitionParser(ProtocolConfig.class, true));registerBeanDefinitionParser("service", new XmenBeanDefinitionParser(ServiceConfigBean.class, true));registerBeanDefinitionParser("referer", new XmenBeanDefinitionParser(RefererConfigBean.class, false));}
}

public class XmenBeanDefinitionParser implements BeanDefinitionParser {private static final Logger LOGGER = LoggerFactory.getLogger(BeanDefinitionParser.class);private final Class<?> beanClass;private final boolean required;public XmenBeanDefinitionParser(Class<?> beanClass, boolean required) {this.beanClass = beanClass;this.required = required;}@Overridepublic BeanDefinition parse(Element element, ParserContext parseContext) {try {return parse(element, parseContext, beanClass, required);} catch (ClassNotFoundException e) {e.printStackTrace();}return null;}private BeanDefinition parse(Element element, ParserContext parserContext, Class<?> beanClass, boolean required) throws ClassNotFoundException {RootBeanDefinition bd = new RootBeanDefinition();bd.setBeanClass(beanClass);bd.setLazyInit(false);String id = element.getAttribute("id");if ((id == null || id.length() == 0) && required) {String generatedBeanName = element.getAttribute("name");if (generatedBeanName == null || generatedBeanName.length() == 0) {generatedBeanName = element.getAttribute("class");}if (generatedBeanName == null || generatedBeanName.length() == 0) {generatedBeanName = beanClass.getName();}id = generatedBeanName;int counter = 2;while (parserContext.getRegistry().containsBeanDefinition(id)) {id = generatedBeanName + (counter++);}}if (id != null) {if (parserContext.getRegistry().containsBeanDefinition(id)) {throw new IllegalStateException("Duplicate spring bean config, id = " + id);}parserContext.getRegistry().registerBeanDefinition(id, bd);}bd.getPropertyValues().addPropertyValue("id", id);if(ServiceConfigBean.class.equals(beanClass)) {String className = element.getAttribute("class");if(className != null && className.length() > 0) {RootBeanDefinition classDefinition = new RootBeanDefinition();classDefinition.setBeanClass(Class.forName(className, true, Thread.currentThread().getContextClassLoader()));classDefinition.setLazyInit(false);bd.getPropertyValues().addPropertyValue("ref", new BeanDefinitionHolder(classDefinition, id + "Impl"));}}for (Method setter : beanClass.getMethods()) {String name = setter.getName();if (name.length() <= 3 || !name.startsWith("set") || !Modifier.isPublic(setter.getModifiers())) {continue;}String property = name.substring(3, 4).toLowerCase() + name.substring(4);if ("id".equals(property)) {bd.getPropertyValues().addPropertyValue("id", id);continue;}String value = element.getAttribute(property);value = value.trim();if (value.length() == 0 || value == null) {continue;}Object reference;if ("ref".equals(property)) {reference = new RuntimeBeanReference(value);} else {reference = new TypedStringValue(value);}bd.getPropertyValues().addPropertyValue(property, reference);}return bd;}
}