Dubbo源码学习--服务是如何引用的-白红宇

Dubbo源码学习--服务是如何引用的

阅读量：4546 次

发布时间：2019-06-08

本文共 8318 字，大约阅读时间需要 27 分钟。

ReferenceBean

跟服务引用一样，Dubbo的reference配置会被转成ReferenceBean类,ReferenceBean实现了InitializingBean接口，直接看afterPropertiesSet()也就是spring为Bean提供的初始化方法

方法调用顺序afterPropertiesSet() -> getObject() -> get() -> init() -> createProxy()

afterPropertiesSet()

afterPropertiesSet()作用为装载应用信息、注册、模块、监控等配置，然后调用getObject()

public void afterPropertiesSet() throws Exception {        //.....        setApplication(applicationConfig);        //.....        setModule(moduleConfig);        //.....        super.setRegistries(registryConfigs);        //.....        Boolean b = isInit();        if (b == null && getConsumer() != null) {            b = getConsumer().isInit();        }        if (b != null && b.booleanValue()) {            getObject();        }    }

getObject()

getObject() 返回 get() 执行结果

public Object getObject() throws Exception {        return get();    }

get()

get() 如果接口代理类（ref) 为空则调用 init() 生成接口代理类

public synchronized T get() {        if (destroyed){            throw new IllegalStateException("Already destroyed!");        }        if (ref == null) {            init();        }        return ref;    }

init()

init() 根据配置生成Map 然后调用 createProxy() 生成代理类

ref = createProxy(map);

createProxy()

具体作用见注释

private T createProxy(Map
    
      map) {        //1. 创建临时Url        URL tmpUrl = new URL("temp", "localhost", 0, map);        final boolean isJvmRefer;        // 省略部分代码.....        //2.判断是否暴漏本地服务        if (isJvmRefer) {            URL url = new URL(Constants.LOCAL_PROTOCOL, NetUtils.LOCALHOST, 0, interfaceClass.getName()).addParameters(map);            invoker = refprotocol.refer(interfaceClass, url);        // 省略部分代码.....        } else {            //3.判断用户指定URL，指定的URL可能是对点对直连地址，也可能是注册中心URL            if (url != null && url.length() > 0) {                 String[] us = Constants.SEMICOLON_SPLIT_PATTERN.split(url);                if (us != null && us.length > 0) {                    for (String u : us) {                        URL url = URL.valueOf(u);                        if (url.getPath() == null || url.getPath().length() == 0) {                            url = url.setPath(interfaceName);                        }                        if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) {                            urls.add(url.addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map)));                        } else {                            urls.add(ClusterUtils.mergeUrl(url, map));                        }                    }                }            } else {                 //4. 通过注册中心配置拼装URL                List
     
       us = loadRegistries(false);                if (us != null && us.size() > 0) {                    for (URL u : us) {                        URL monitorUrl = loadMonitor(u);                        if (monitorUrl != null) {                            map.put(Constants.MONITOR_KEY, URL.encode(monitorUrl.toFullString()));                        }                        urls.add(u.addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map)));                    }                }                if (urls == null || urls.size() == 0) {                    throw new IllegalStateException("No such any registry to reference " + interfaceName  + " on the consumer " + NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion() + ", please config 
       to your spring config.");                }            }            // 5.调用refprotocol.refer()            if (urls.size() == 1) {                invoker = refprotocol.refer(interfaceClass, urls.get(0));            } else {                List
      
       > invokers = new ArrayList
       
        >();                URL registryURL = null;                for (URL url : urls) {                    invokers.add(refprotocol.refer(interfaceClass, url));                    if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) {                        registryURL = url; // 用了最后一个registry url                    }                }                if (registryURL != null) { // 有 注册中心协议的URL                    // 对有注册中心的Cluster 只用 AvailableCluster                    URL u = registryURL.addParameter(Constants.CLUSTER_KEY, AvailableCluster.NAME);                     invoker = cluster.join(new StaticDirectory(u, invokers));                }  else { // 不是 注册中心的URL                    invoker = cluster.join(new StaticDirectory(invokers));                }            }        }        // 省略.....        // 6.创建服务代理        return (T) proxyFactory.getProxy(invoker);    }

RegistryProtocol

refprotocol.refer()

refprotocol.refer() 先后经过修饰类 ProtocolFilterWrapper、ProtocolListenerWrapper 最后执行RegistryProtocol

ProtocolFilterWrapper -> ProtocolListenerWrapper

//ProtocolFilterWrapper    public 
    
      Invoker
     
       refer(Class
      
        type, URL url) throws RpcException {        if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) {            return protocol.refer(type, url);        }        return buildInvokerChain(protocol.refer(type, url), Constants.REFERENCE_FILTER_KEY, Constants.CONSUMER);    }        //ProtocolListenerWrapper    public 
       
         Invoker
        
          refer(Class
         
           type, URL url) throws RpcException { if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) { return protocol.refer(type, url); } return new ListenerInvokerWrapper
          
           (protocol.refer(type, url), Collections.unmodifiableList( ExtensionLoader.getExtensionLoader(InvokerListener.class) .getActivateExtension(url, Constants.INVOKER_LISTENER_KEY))); }

RegistryProtocol

@SuppressWarnings("unchecked")    public 
    
      Invoker
     
       refer(Class
      
        type, URL url) throws RpcException {        // Constants.REGISTRY_KEY: registry         // Constants.DEFAULT_REGISTRY: dubbo        url = url.setProtocol(url.getParameter(Constants.REGISTRY_KEY, Constants.DEFAULT_REGISTRY)).removeParameter(Constants.REGISTRY_KEY);        Registry registry = registryFactory.getRegistry(url);        if (RegistryService.class.equals(type)) {            return proxyFactory.getInvoker((T) registry, type, url);        }        // 配置Group信息        // group="a,b" or group="*"        Map
       
         qs = StringUtils.parseQueryString(url.getParameterAndDecoded(Constants.REFER_KEY)); // Constants.REFER_KEY:refer        String group = qs.get(Constants.GROUP_KEY);        if (group != null && group.length() > 0 ) {            if ( ( Constants.COMMA_SPLIT_PATTERN.split( group ) ).length > 1                    || "*".equals( group ) ) {                return doRefer( getMergeableCluster(), registry, type, url );            }        }        return doRefer(cluster, registry, type, url);    }

doRefer()

调用FailbackRegistry.register() 在注册中心注册消费者subscribeUrl

调用FailbackRegistry.subscribe() 订阅注册中心subscribeUrl

private 
    
      Invoker
     
       doRefer(Cluster cluster, Registry registry, Class
      
        type, URL url) {        RegistryDirectory
       
         directory = new RegistryDirectory
        
         (type, url);        directory.setRegistry(registry);        directory.setProtocol(protocol);        // Constants.CONSUMER_PROTOCOL: consumer        URL subscribeUrl = new URL(Constants.CONSUMER_PROTOCOL, NetUtils.getLocalHost(), 0, type.getName(), directory.getUrl().getParameters());                //consumer://10.9.22.12/com.**.ShopService?application=test&check=false&dubbo=2.8.4        //&interface=com.**.ShopService&methods=getList&pid=6168&retries=1&revision=1.0-SNAPSHOT        //&side=consumer&timeout=6000&timestamp=1484275807134&version=1.0        if (! Constants.ANY_VALUE.equals(url.getServiceInterface())                && url.getParameter(Constants.REGISTER_KEY, true)) {            registry.register(subscribeUrl.addParameters(Constants.CATEGORY_KEY, Constants.CONSUMERS_CATEGORY,                    Constants.CHECK_KEY, String.valueOf(false)));        }        directory.subscribe(subscribeUrl.addParameter(Constants.CATEGORY_KEY,                 Constants.PROVIDERS_CATEGORY                 + "," + Constants.CONFIGURATORS_CATEGORY                 + "," + Constants.ROUTERS_CATEGORY));        return cluster.join(directory);    }