五：Dubbo上版本Provider

五：Dubbo上版本Provider dubbo.application.register-mode 参数参数含义interface只接口级注册（/dubbo）instance只应用级注册（/service）all接口级注册与应用级注册并存（/dubbo && /service） dubbo.application.service-discovery.migration 参数参数含义FORCE_INTERFACE只消费接口级地址，如无地址则报错，单订阅2.x地址APPLICATION_FIRST智能决策接口级还是应用级地址，双订阅 （先查询接口级 在查询应用级）FORCE_APPLICATION只消费应用级地址，如无地址则报错，单订阅3.x地址 源码解析

在上一节中有说到 服务启动流程 中会执行到不同版本的
org.apache.dubbo.config.ServiceConfig#exportOnly
或者
org.apache.dubbo.config.ServiceConfig#export
方法， 在方法内部调用
List registryURLs = ConfigValidationUtils.loadRegistries(this, true);
获取URL， 我们具体看下 该方法调用

	//org.apache.dubbo.config.utils.ConfigValidationUtils#loadRegistries
    public static List loadRegistries(AbstractInterfaceConfig interfaceConfig, boolean provider) {
        // 此处调用是为了得到 register协议的URL
        //eg: registry://127.0.0.1:2181/org.apache.dubbo.registry.RegistryService?application=provider&client=curator&dubbo=2.0.2&pid=8093®istry=zookeeper&release=3.0.4×tamp=1640861452691
        List registryList = new ArrayList();
        ApplicationConfig application = interfaceConfig.getApplication();
        List registries = interfaceConfig.getRegistries();
        if (CollectionUtils.isNotEmpty(registries)) {
            for (RegistryConfig config : registries) {
                String address = config.getAddress();
                if (StringUtils.isEmpty(address)) {
                    address = ANYHOST_VALUE;
                }
                if (!RegistryConfig.NO_AVAILABLE.equalsIgnoreCase(address)) {
                    Map map = new HashMap();
                    AbstractConfig.appendParameters(map, application);
                    AbstractConfig.appendParameters(map, config);
                    map.put(PATH_KEY, RegistryService.class.getName());
                    AbstractInterfaceConfig.appendRuntimeParameters(map);
                    if (!map.containsKey(PROTOCOL_KEY)) {
                        map.put(PROTOCOL_KEY, DUBBO_PROTOCOL);
                    }
                    List urls = UrlUtils.parseURLs(address, map);

                    for (URL url : urls) {
                        url = URLBuilder.from(url)
                            .addParameter(REGISTRY_KEY, url.getProtocol())
                            .setProtocol(extractRegistryType(url))
                            .setScopeModel(interfaceConfig.getScopeModel())
                            .build();
                        if ((provider && url.getParameter(REGISTER_KEY, true))
                            || (!provider && url.getParameter(SUBSCRIBE_KEY, true))) {
                            registryList.add(url);
                        }
                    }
                }
            }
        }
        //此处会对register-mode做判断
        return genCompatibleRegistries(interfaceConfig.getScopeModel(), registryList, provider);
    }

	//org.apache.dubbo.config.utils.ConfigValidationUtils#genCompatibleRegistries
    private static List genCompatibleRegistries(ScopeModel scopeModel, List registryList, boolean provider) {
        List result = new ArrayList<>(registryList.size());
        registryList.forEach(registryURL -> {
        	//判断是否为 provider
            if (provider) {
                String registerMode;
                //判断是否为 service-discovery-registry 协议
                if (SERVICE_REGISTRY_PROTOCOL.equals(registryURL.getProtocol())) {
                    //获取定义的register-mode值
                    registerMode = registryURL.getParameter(REGISTER_MODE_KEY, ConfigurationUtils.getCachedDynamicProperty(scopeModel, DUBBO_REGISTER_MODE_DEFAULT_KEY, DEFAULT_REGISTER_MODE_INSTANCE));
                    if (!isValidRegisterMode(registerMode)) {
                        registerMode = DEFAULT_REGISTER_MODE_INSTANCE;
                    }
                    result.add(registryURL);
                    //判断register_mode 是否 为all模式 并且 registryURL不是registry协议
                    if (DEFAULT_REGISTER_MODE_ALL.equalsIgnoreCase(registerMode)
                        && registryNotExists(registryURL, registryList, REGISTRY_PROTOCOL)) {
                        URL interfaceCompatibleRegistryURL = URLBuilder.from(registryURL)
                            .setProtocol(REGISTRY_PROTOCOL)
                            .removeParameter(REGISTRY_TYPE_KEY)
                            .build();
                        result.add(interfaceCompatibleRegistryURL);
                    }
                } else {
                	//进来此处说明 registryURL的协议为 registry
                	
                	//获取定义的register-mode值
                    registerMode = registryURL.getParameter(REGISTER_MODE_KEY, ConfigurationUtils.getCachedDynamicProperty(scopeModel, DUBBO_REGISTER_MODE_DEFAULT_KEY, DEFAULT_REGISTER_MODE_ALL));
                    if (!isValidRegisterMode(registerMode)) {
                        registerMode = DEFAULT_REGISTER_MODE_INTERFACE;
                    }
                    //如果register-mode的值定义的为 instance 或 all
                    if ((DEFAULT_REGISTER_MODE_INSTANCE.equalsIgnoreCase(registerMode) || DEFAULT_REGISTER_MODE_ALL.equalsIgnoreCase(registerMode))
                        && registryNotExists(registryURL, registryList, SERVICE_REGISTRY_PROTOCOL)) {
                        //封装为service-discovery-registry协议
                        URL serviceDiscoveryRegistryURL = URLBuilder.from(registryURL)
                            .setProtocol(SERVICE_REGISTRY_PROTOCOL)
                            .removeParameter(REGISTRY_TYPE_KEY)
                            .build();
					     //将service-discovery-registry协议的URL加入到集合
					     result.add(serviceDiscoveryRegistryURL);
                    }
					//如果register-mode的值定义的为 interface 或 all
                    if (DEFAULT_REGISTER_MODE_INTERFACE.equalsIgnoreCase(registerMode) || DEFAULT_REGISTER_MODE_ALL.equalsIgnoreCase(registerMode)) {
                        //将registry协议的URL加入到集合
                        result.add(registryURL);
                    }
                }

                frameworkStatusReportService reportService = ScopeModelUtil.getApplicationModel(scopeModel).getBeanFactory().getBean(frameworkStatusReportService.class);
                reportService.reportRegistrationStatus(reportService.createRegistrationReport(registerMode));
            } else {
                result.add(registryURL);
            }
        });

        return result;
    }