7.8 服务暴露总结

服务提供端配置：

    <!-- 提供方应用信息，用于计算依赖关系 -->
    <dubbo:application name="demo-provider"/>

    <!-- 使用zookeeper注册中心，并使用curator客户端 -->
    <dubbo:registry protocol="zookeeper" address="10.211.55.5:2181" client="curator"/>

    <!-- 用dubbo协议在20880端口暴露服务 -->
    <dubbo:protocol name="dubbo" port="20880"/>

    <!-- 和本地bean一样实现服务 -->
    <bean id="demoService" class="com.alibaba.dubbo.demo.provider.DemoServiceImpl"/>

    <!-- 声明需要暴露的服务接口 -->
    <dubbo:service interface="com.alibaba.dubbo.demo.DemoService" ref="demoService"/>

一 ServiceBean

1 继承实现关系

2 最终的ServiceBean实例

-->String id: "com.alibaba.dubbo.demo.DemoService"
-->String beanName: "com.alibaba.dubbo.demo.DemoService"
-->ApplicationContext applicationContext: ClassPathXmlApplicationContext实例
-->supportedApplicationListener:true
-->List<URL> urls: ["dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&timestamp=1510023456461"]
-->List<Exporter<?>> exporters:[
  -->InjvmExporter实例
    -->String key:com.alibaba.dubbo.demo.DemoService
    -->Map<String, Exporter<?>> exporterMap: {"com.alibaba.dubbo.demo.DemoService ", 当前的JvmExporter实例}
    -->Invoker invoker：经过filter包装的AbstractProxyInvoker实例
  -->RegistryProtocol返回的新的Exporter实例
    -->Exporter exporter: ExporterChangeableWrapper<T> exporter实例
      -->Invoker originInvoker：经过filter包装的AbstractProxyInvoker实例
      -->Exporter exporter: DubboExporter
    -->Registry registry: 上边的ZookeeperRegistry实例
]
-->String interfaceName:"com.alibaba.dubbo.demo.DemoService"
-->Class<?> interfaceClass:interface com.alibaba.dubbo.demo.DemoService
-->T ref: DemoServiceImpl实例
-->String path:"com.alibaba.dubbo.demo.DemoService"
-->List<ProtocolConfig> protocols:[解析：<dubbo:protocol name="dubbo" port="20880" id="dubbo" />]
-->ApplicationConfig application:[解析：<dubbo:application name="demo-provider" id="demo-provider" />]
-->List<RegistryConfig> registries:[解析：<dubbo:registry address="10.211.55.5:2181" protocol="zookeeper" id="com.alibaba.dubbo.config.RegistryConfig" />]

二 调用简图

三 代码调用链

ServiceBean.onApplicationEvent(ApplicationEvent event)
-->ServiceConfig.export()
  -->doExport()
    -->doExportUrls()
      -->doExportUrlsFor1Protocol(ProtocolConfig protocolConfig, List<URL> registryURLs)
         protocolConfig：<dubbo:protocol name="dubbo" port="20880" id="dubbo" /> 
         registryURLs：registry://10.211.55.5:2181/com.alibaba.dubbo.registry.RegistryService?application=demo-provider&client=curator&dubbo=2.0.0&pid=3141&registry=zookeeper&timestamp=1510021313960
      	<!-- 一 本地暴露 -->
        -->exportLocal(url)
           url：dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3141&side=provider&timestamp=1510021401013
          //1.1 将实现类ref封装成Invoker
          -->JavassistProxyFactory.getInvoker(T proxy, Class<T> type, URL url)
             proxy：DemoServiceImpl实例（即ref实例） 
             type：interface com.alibaba.dubbo.demo.DemoService  
             url：injvm://127.0.0.1/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3141&side=provider&timestamp=1510021401013
            -->Wrapper.getWrapper(Class DemoServiceImpl)
            -->new AbstractProxyInvoker<T>(proxy, type, url)
          //1.2 将实现类Invoker暴露为Exporter
          -->ProtocolFilterWrapper.buildInvokerChain(final Invoker<T> invoker, String key, String group)
             组建invoker链，实际上只有最后一个是真正的AbstractProxyInvoker实例，前边的都是filter。
             invoker:AbstractProxyInvoker实例 
             key：service.filter 
             group：provider
          -->InjvmProtocol.export(Invoker<T> invoker)
             invoker：经过filter包装的invoker
            -->new InjvmExporter(Invoker<T> invoker, String key, Map<String, Exporter<?>> exporterMap)
               invoker：经过filter包装的invoker 
               key:com.alibaba.dubbo.demo.DemoService 
               exporterMap:传入时为空，构造器执行后为{"com.alibaba.dubbo.demo.DemoService ", 当前的JvmExporter实例}
          -->List<Exporter<?>> exporters.add(上述的exporter)
        <!-- 二 远程暴露 -->
        //2.1 将实现类ref封装成Invoker
        -->JavassistProxyFactory.getInvoker(T proxy, Class<T> type, URL url)
           proxy：DemoServiceImpl实例（即ref实例） 
           type：interface com.alibaba.dubbo.demo.DemoService  
           url：registry://10.211.55.5:2181/com.alibaba.dubbo.registry.RegistryService?application=demo-provider&client=curator&dubbo=2.0.0&export=dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3141&side=provider&timestamp=1510021401013&pid=3141&registry=zookeeper&timestamp=1510021313960
          -->Wrapper.getWrapper(Class DemoServiceImpl)
          -->new AbstractProxyInvoker<T>(proxy, type, url)
        -->RegistryProtocol.export(final Invoker<T> originInvoker)
           originInvoker：上述的AbstractProxyInvoker实例
          //2.2 将invoker转化为exporter
          -->doLocalExport(originInvoker)
            -->new InvokerDelegete(Invoker<T> invoker, URL url)
               invoker：原始的AbstractProxyInvoker实例
               url：dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&timestamp=1510023456461
            -->ProtocolFilterWrapper.buildInvokerChain(final Invoker<T> invoker, String key, String group)
               组建invoker链，实际上只有最后一个是真正的InvokerDelegete实例，前边的都是filter
               invoker:InvokerDelegete实例 
               key：service.filter 
               group：provider
            -->DubboProtocol.export(Invoker<T> invoker)
               invoker：经过filter包装的InvokerDelegete实例
              -->new DubboExporter(Invoker<T> invoker, String key, Map<String, Exporter<?>> exporterMap)
                 invoker：经过filter包装的InvokerDelegete实例 
                 key:com.alibaba.dubbo.demo.DemoService:20880 (group/servicename:version:port)
                 exporterMap:传入时为空，构造器执行后又执行了put，为{"com.alibaba.dubbo.demo.DemoService:20880", 当前的DubboExporter实例}
              //2.3 开启netty服务端监听客户端请求
              -->openServer(URL url)
                 url：dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&timestamp=1510023456461
                -->createServer(URL url)
                    -->HeaderExchanger.bind(URL url, ExchangeHandler handler)
                       url：dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&channel.readonly.sent=true&codec=dubbo&dubbo=2.0.0&generic=false&heartbeat=60000&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&timestamp=1510023456461 handler:DubboProtocol.requestHandler
                      -->new DecodeHandler(new HeaderExchangeHandler(handler)))
                        -->NettyTransporter.bind(URL url, ChannelHandler listener)
                           url:dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&channel.readonly.sent=true&codec=dubbo&dubbo=2.0.0&generic=false&heartbeat=60000&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&timestamp=1510023456461  listener:上边的DecodeHandler实例
                          -->new NettyServer(URL url, ChannelHandler handler)
                            -->ChannelHandler.wrapInternal(ChannelHandler handler, URL url)
                               handler:上边的DecodeHandler实例 
                               url:dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&channel.readonly.sent=true&codec=dubbo&dubbo=2.0.0&generic=false&heartbeat=60000&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&threadname=DubboServerHandler-10.10.10.10:20880&timestamp=1510023456461
                              -->new MultiMessageHandler(HeartbeatHandler(AllChannelHandler(handler)))
                            -->getChannelCodec(url)//获取Codec2，这里是DubboCountCodec实例
                            -->doOpen()//开启netty服务
                      -->new HeaderExchangeServer(Server server)
                         server:上述的NettyServer
                        -->startHeatbeatTimer()
            -->new ExporterChangeableWrapper(Exporter<T> exporter, Invoker<T> originInvoker)
               exporter:上述的DubboExporter实例  
               originInvoker：原始的AbstractProxyInvoker实例
          //2.4 创建Registry：创建zkclient，连接zk
          -->getRegistry(final Invoker<?> originInvoker)
            -->AbstractRegistryFactory.getRegistry(URL url)
               url：zookeeper://10.211.55.5:2181/com.alibaba.dubbo.registry.RegistryService?application=demo-provider&dubbo=2.0.0&export=dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&timestamp=1510023456461&pid=3508&timestamp=1510023439825
              -->ZookeeperRegistryFactory.createRegistry(URL url)
                -->new ZookeeperRegistry(URL url, ZookeeperTransporter zookeeperTransporter)
                   url:zookeeper://10.211.55.5:2181/com.alibaba.dubbo.registry.RegistryService?application=demo-provider&dubbo=2.0.0&interface=com.alibaba.dubbo.registry.RegistryService&pid=3508&timestamp=1510023439825
                  -->ZkclientZookeeperTransporter.connect(URL url)
                    -->new ZkclientZookeeperClient(URL url)
                       url：zookeeper://10.211.55.5:2181/com.alibaba.dubbo.registry.RegistryService?application=demo-provider&dubbo=2.0.0&interface=com.alibaba.dubbo.registry.RegistryService&pid=3508&timestamp=1510023439825
                      -->new ZkClient(url.getBackupAddress())//这里是10.211.55.5:2181
            -->AbstractRegistryFactory.Map<String, Registry> REGISTRIES.put("zookeeper://10.211.55.5:2181/com.alibaba.dubbo.registry.RegistryService", 上边的ZookeeperRegistry实例)
          //2.5 向注册中心注册服务
          -->registry.register(registedProviderUrl)
            -->ZookeeperRegistry.doRegister(URL url)
               url：dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&timestamp=1510023456461
              -->AbstractZookeeperClient.create(String path, boolean ephemeral)
                 path:/dubbo/com.alibaba.dubbo.demo.DemoService/providers/dubbo://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&timestamp=1510023456461  
                 ephemeral=true
          //2.6 订阅override数据
          -->ZookeeperRegistry.doSubscribe(final URL url, final NotifyListener listener)
             url：provider://10.10.10.10:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&category=configurators&check=false&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=3508&side=provider&timestamp=1510023456461  
             listener：RegistryProtocol.OverrideListener实例
          //2.7 创建新的Exporter实例
          -->new Exporter<T>()//包含了上边的ExporterChangeableWrapper<T> exporter实例 + ZookeeperRegistry实例