服务发布-原理
第一个发布的动作：暴露本地服务
Export dubbo service com.alibaba.dubbo.demo.DemoService to local registry, dubbo version: 2.0.0, current host: 127.0.0.1
第二个发布动作：暴露远程服务
Export dubbo service com.alibaba.dubbo.demo.DemoService to url dubbo://192.168.100.38:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&loadbalance=roundrobin&methods=sayHello&owner=william&pid=8484&side=provider×tamp=1473908495465, dubbo version: 2.0.0, current host: 127.0.0.1
Register dubbo service com.alibaba.dubbo.demo.DemoService url dubbo://192.168.100.38:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&loadbalance=roundrobin&methods=sayHello&monitor=dubbo%3A%2F%2F192.168.48.117%3A2181%2Fcom.alibaba.dubbo.registry.RegistryService%3Fapplication%3Ddemo-provider%26backup%3D192.168.48.120%3A2181%2C192.168.48.123%3A2181%26dubbo%3D2.0.0%26owner%3Dwilliam%26pid%3D8484%26protocol%3Dregistry%26refer%3Ddubbo%253D2.0.0%2526interface%253Dcom.alibaba.dubbo.monitor.MonitorService%2526pid%253D8484%2526timestamp%253D1473908495729%26registry%3Dzookeeper%26timestamp%3D1473908495398&owner=william&pid=8484&side=provider×tamp=1473908495465 to registry registry://192.168.48.117:2181/com.alibaba.dubbo.registry.RegistryService?application=demo-provider&backup=192.168.48.120:2181,192.168.48.123:2181&dubbo=2.0.0&owner=william&pid=8484®istry=zookeeper×tamp=1473908495398, dubbo version: 2.0.0, current host: 127.0.0.1
第三个发布动作：启动netty
Start NettyServer bind /0.0.0.0:20880, export /192.168.100.38:20880, dubbo version: 2.0.0, current host: 127.0.0.1
第四个发布动作：打开连接zk
INFO zookeeper.ClientCnxn: Opening socket connection to server /192.168.48.117:2181
第五个发布动作：到zk注册
Register: dubbo://192.168.100.38:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&loadbalance=roundrobin&methods=sayHello&owner=william&pid=8484&side=provider×tamp=1473908495465, dubbo version: 2.0.0, current host: 127.0.0.1
第六个发布动作；监听zk
Subscribe: provider://192.168.100.38:20880/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&loadbalance=roundrobin&methods=sayHello&owner=william&pid=8484&side=provider×tamp=1473908495465, dubbo version: 2.0.0, current host: 127.0.0.1
Notify urls for subscribe url provider://192.168.100.38:20880/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&loadbalance=roundrobin&methods=sayHello&owner=william&pid=8484&side=provider×tamp=1473908495465, urls: [empty://192.168.100.38:20880/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&loadbalance=roundrobin&methods=sayHello&owner=william&pid=8484&side=provider×tamp=1473908495465], dubbo version: 2.0.0, current host: 127.0.0.1
暴露本地服务和暴露远程服务的区别是什么？
1.暴露本地服务：指暴露在用一个JVM里面，不用通过调用zk来进行远程通信。例如：在同一个服务，自己调用自己的接口，就没必要进行网络IP连接来通信。
2.暴露远程服务：指暴露给远程客户端的IP和端口号，通过网络来实现通信。
zk持久化节点 和临时节点有什么区别？
持久化节点：一旦被创建，触发主动删除掉，否则就一直存储在ZK里面。
临时节点：与客户端会话绑定，一旦客户端会话失效，这个客户端端所创建的所有临时节点都会被删除。
ServiceBean.onApplicationEvent
-->export()
-->ServiceConfig.export()
-->doExport()
-->doExportUrls()//里面有一个for循环，代表了一个服务可以有多个通信协议，例如 tcp协议 http协议，默认是tcp协议
-->loadRegistries(true)//从dubbo.properties里面组装registry的url信息
-->doExportUrlsFor1Protocol(ProtocolConfig protocolConfig, List<URL> registryURLs)
//配置不是remote的情况下做本地暴露 (配置为remote，则表示只暴露远程服务)
-->exportLocal(URL url)
-->proxyFactory.getInvoker(ref, (Class) interfaceClass, local)
-->ExtensionLoader.getExtensionLoader(com.alibaba.dubbo.rpc.ProxyFactory.class).getExtension("javassist");
-->extension.getInvoker(arg0, arg1, arg2)
-->StubProxyFactoryWrapper.getInvoker(T proxy, Class<T> type, URL url)
-->proxyFactory.getInvoker(proxy, type, url)
-->JavassistProxyFactory.getInvoker(T proxy, Class<T> type, URL url)
-->Wrapper.getWrapper(com.alibaba.dubbo.demo.provider.DemoServiceImpl)
-->makeWrapper(Class<?> c)
-->return new AbstractProxyInvoker<T>(proxy, type, url)
-->protocol.export
-->ProtocolAdpative.export
-->ExtensionLoader.getExtensionLoader(com.alibaba.dubbo.rpc.Protocol.class).getExtension("registry");
-->extension.export(arg0)
-->ProtocolFilterWrapper.export
-->ProtocolListenerWrapper.export
-->RegistryProtocol.export
-->doLocalExport(originInvoker)
-->getCacheKey(originInvoker);//读取 dubbo://192.168.100.51:20880/
-->rotocol.export
-->ProtocolAdpative.bind
-->ExtensionLoader.getExtensionLoader(com.alibaba.dubbo.remoting.Transporter.class).getExtension("netty");
-->extension.bind(arg0, arg1)
-->NettyTransporter.bind
--new NettyServer(url, listener)
-->AbstractPeer //this.url = url; this.handler = handler;
-->AbstractEndpoint//codec timeout=1000 connectTimeout=3000
-->AbstractServer //bindAddress accepts=0 idleTimeout=600000
---------4.打开断开，暴露netty服务-------------------------------->doOpen()
-->设置 NioServerSocketChannelFactory boss worker的线程池 线程个数为3
-->设置编解码 hander
-->bootstrap.bind(getBindAddress())
-->new HeaderExchangeServer
-->this.server=NettyServer
-->heartbeat=60000
-->heartbeatTimeout=180000
-->startHeatbeatTimer()//这是一个心跳定时器，采用了线程池，如果断开就心跳重连。
-->getRegistry(originInvoker)//zk 连接
-->registryFactory.getRegistry(registryUrl)
-->ExtensionLoader.getExtensionLoader(RegistryFactory.class).getExtension("zookeeper");
-->extension.getRegistry(arg0)
-->AbstractRegistryFactory.getRegistry//创建一个注册中心，存储在REGISTRIES
-->createRegistry(url)
-->new ZookeeperRegistry(url, zookeeperTransporter)
-->AbstractRegistry
-->loadProperties()//目的：把C:\Users\bobo\.dubbo\dubbo-registry-192.168.48.117.cache
文件中的内容加载为properties
-->notify(url.getBackupUrls())//不做任何事
-->FailbackRegistry
-->retryExecutor.scheduleWithFixedDelay(new Runnable()//建立线程池，检测并连接注册中心,如果失败了就重连
-->ZookeeperRegistry
-->zookeeperTransporter.connect(url)
-->ZookeeperTransporter$Adpative.connect(url)
-->ExtensionLoader.getExtensionLoader(ZookeeperTransporter.class).getExtension("zkclient");
-->extension.connect(arg0)
-->ZkclientZookeeperTransporter.connect
-->new ZkclientZookeeperClient(url)
-->AbstractZookeeperClient
-->ZkclientZookeeperClient
-->new ZkClient(url.getBackupAddress());//连接ZK
-->client.subscribeStateChanges(new IZkStateListener()//订阅的目标：连接断开，重连
-->zkClient.addStateListener(new StateListener()
-->recover //连接失败 重连
-->registry.register(registedProviderUrl)//创建节点
-->AbstractRegistry.register
-->FailbackRegistry.register
-->doRegister(url)//向zk服务器端发送注册请求
-->ZookeeperRegistry.doRegister
-->zkClient.create
-->AbstractZookeeperClient.create//dubbo/com.alibaba.dubbo.demo.DemoService/providers/
dubbo%3A%2F%2F192.168.100.52%3A20880%2Fcom.alibaba.dubbo.demo.DemoService%3Fanyhost%3Dtrue%26
application%3Ddemo-provider%26dubbo%3D2.0.0%26generic%3Dfalse%26interface%3D
com.alibaba.dubbo.demo.DemoService%26loadbalance%3Droundrobin%26methods%3DsayHello%26owner%3
Dwilliam%26pid%3D2416%26side%3Dprovider%26timestamp%3D1474276306353
-->createEphemeral(path);//临时节点 dubbo%3A%2F%2F192.168.100.52%3A20880%2F.............
-->createPersistent(path);//持久化节点 dubbo/com.alibaba.dubbo.demo.DemoService/providers
-->registry.subscribe//订阅ZK
-->AbstractRegistry.subscribe
-->FailbackRegistry.subscribe
-->doSubscribe(url, listener)// 向服务器端发送订阅请求
-->ZookeeperRegistry.doSubscribe
-->new ChildListener()
-->实现了 childChanged
-->实现并执行 ZookeeperRegistry.this.notify(url, listener, toUrlsWithEmpty(url, parentPath, currentChilds));
//A
-->zkClient.create(path, false);//第一步：先创建持久化节点/dubbo/com.alibaba.dubbo.demo.DemoService/configurators
-->zkClient.addChildListener(path, zkListener)
-->AbstractZookeeperClient.addChildListener
//C
-->createTargetChildListener(path, listener)//第三步：收到订阅后的处理，交给FailbackRegistry.notify处理
-->ZkclientZookeeperClient.createTargetChildListener
-->new IZkChildListener()
-->实现了 handleChildChange //收到订阅后的处理
-->listener.childChanged(parentPath, currentChilds);
-->实现并执行ZookeeperRegistry.this.notify(url, listener, toUrlsWithEmpty(url, parentPath, currentChilds));
-->收到订阅后处理 FailbackRegistry.notify
//B
-->addTargetChildListener(path, targetListener)////第二步
-->ZkclientZookeeperClient.addTargetChildListener
-->client.subscribeChildChanges(path, listener)//第二步：启动加入订阅/dubbo/com.alibaba.dubbo.demo.DemoService/configurators
-->notify(url, listener, urls)
-->FailbackRegistry.notify
-->doNotify(url, listener, urls);
-->AbstractRegistry.notify
-->saveProperties(url);//把服务端的注册url信息更新到C:\Users\bobo\.dubbo\dubbo-registry-192.168.48.117.cache
-->registryCacheExecutor.execute(new SaveProperties(version));//采用线程池来处理
-->listener.notify(categoryList)
-->RegistryProtocol.notify
-->RegistryProtocol.this.getProviderUrl(originInvoker)//通过invoker的url 获取 providerUrl的地址
