Merge pull request #1 from alibaba/master

update

README-zh.md

@@ -48,15 +48,16 @@ Spring Cloud Alibaba 致力于提供微服务开发的一站式解决方案。
 更多组件请参考 [Roadmap](https://github.com/alibaba/spring-cloud-alibaba/blob/master/Roadmap-zh.md)。
 
 ## 如何构建
-
+* 2020.0 分支对应的是 Spring Cloud 2020，最低支持 JDK 1.8。
-* master 分支对应的是 Spring Cloud Greenwich，最低支持 JDK 1.8。
+* master 分支对应的是 Spring Cloud Hoxton，最低支持 JDK 1.8。
+* greenwich 分支对应的是 Spring Cloud Greenwich，最低支持 JDK 1.8。
 * finchley 分支对应的是 Spring Cloud Finchley，最低支持 JDK 1.8。
 * 1.x 分支对应的是 Spring Cloud Edgware，最低支持 JDK 1.7。
 
 Spring Cloud 使用 Maven 来构建，最快的使用方式是将本项目 clone 到本地，然后执行以下命令：
-
+```bash
 	./mvnw install
-
+```
 执行完毕后，项目将被安装到本地 Maven 仓库。
 
 ## 如何使用
@@ -64,7 +65,7 @@ Spring Cloud 使用 Maven 来构建，最快的使用方式是将本项目 clone
 ### 如何引入依赖
 
 如果需要使用已发布的版本，在 `dependencyManagement` 中添加如下配置。
-
+```xml
 	<dependencyManagement>
         <dependencies>
             <dependency>
@@ -76,7 +77,7 @@ Spring Cloud 使用 Maven 来构建，最快的使用方式是将本项目 clone
             </dependency>
         </dependencies>
     </dependencyManagement>
-
+```
 然后在 `dependencies` 中添加自己所需使用的依赖即可使用。
 
 ## 演示 Demo
@@ -111,7 +112,7 @@ Example 列表：
 * 2.0.x 版本适用于 Spring Boot 2.0.x
 * 2.1.x 版本适用于 Spring Boot 2.1.x
 * 2.2.x 版本适用于 Spring Boot 2.2.x
-
+* 2021.x 版本适用于 Spring Boot 2.4.x
 
 ## 社区交流
 

README.md

@@ -51,22 +51,23 @@ For more features, please refer to [Roadmap](https://github.com/alibaba/spring-c
 For more features please refer to [Roadmap](https://github.com/alibaba/spring-cloud-alibaba/blob/master/Roadmap.md).
 
 ## How to build
-
+* **2020.0 branch**: Corresponds to Spring Cloud 2020 & Spring Boot 2.4.x. JDK 1.8 or later versions are supported.
-* **master branch**: Corresponds to Spring Cloud Greenwich & Spring Boot 2.x. JDK 1.8 or later versions are supported.
+* **master branch**: Corresponds to Spring Cloud Hoxton & Spring Boot 2.2.x. JDK 1.8 or later versions are supported.
-* **finchley branch**: Corresponds to Spring Cloud Finchley & Spring Boot 2.x. JDK 1.8 or later versions are supported.
+* **greenwich branch**: Corresponds to Spring Cloud Greenwich & Spring Boot 2.1.x. JDK 1.8 or later versions are supported.
+* **finchley branch**: Corresponds to Spring Cloud Finchley & Spring Boot 2.0.x. JDK 1.8 or later versions are supported.
 * **1.x branch**: Corresponds to Spring Cloud Edgware & Spring Boot 1.x, JDK 1.7 or later versions are supported.
 
 Spring Cloud uses Maven for most build-related activities, and you should be able to get off the ground quite quickly by cloning the project you are interested in and typing:
-
+```bash
 	./mvnw install
-
+```
 
 ## How to Use
 
 ### Add maven dependency 
 
 These artifacts are available from Maven Central and Spring Release repository via BOM:
-
+```xml
 	<dependencyManagement>
         <dependencies>
             <dependency>
@@ -78,7 +79,7 @@ These artifacts are available from Maven Central and Spring Release repository v
             </dependency>
         </dependencies>
     </dependencyManagement>
-
+```
 add the module in  `dependencies`.
 
 
@@ -118,6 +119,7 @@ As the interfaces and annotations of Spring Boot 1 and Spring Boot 2 have been c
 * 2.0.x for Spring Boot 2.0.x
 * 2.1.x for Spring Boot 2.1.x
 * 2.2.x for Spring Boot 2.2.x
+* 2020.x for Spring Boot 2.4.x
 
 ## Code of Conduct
 This project is a sub-project of Spring Cloud, it adheres to the Contributor Covenant [code of conduct](https://github.com/spring-cloud/spring-cloud-build/blob/master/docs/src/main/asciidoc/code-of-conduct.adoc). By participating, you are expected to uphold this code. Please report unacceptable behavior to spring-code-of-conduct@pivotal.io.

spring-cloud-alibaba-dependencies/pom.xml

@@ -21,7 +21,7 @@
         <revision>2.2.6-SNAPSHOT</revision>
         <sentinel.version>1.8.1</sentinel.version>
         <seata.version>1.3.0</seata.version>
-        <nacos.client.version>1.4.1</nacos.client.version>
+        <nacos.client.version>1.4.2</nacos.client.version>
         <nacos.config.version>0.8.0</nacos.config.version>
         <spring.context.support.version>1.0.10</spring.context.support.version>
 

spring-cloud-alibaba-docs/src/main/asciidoc-zh/nacos-config.adoc

@@ -260,7 +260,7 @@ Nacos 内部有 https://nacos.io/zh-cn/docs/concepts.html[Namespace 的概念]:
 [quote]
 用于进行租户粒度的配置隔离。不同的命名空间下，可以存在相同的 Group 或 Data ID 的配置。Namespace 的常用场景之一是不同环境的配置的区分隔离，例如开发测试环境和生产环境的资源（如配置、服务）隔离等。
 
-在没有明确指定 `${spring.cloud.nacos.config.namespace}` 配置的情况下， 默认使用的是 Nacos 上 Public 这个namespae。如果需要使用自定义的命名空间，可以通过以下配置来实现：
+在没有明确指定 `${spring.cloud.nacos.config.namespace}` 配置的情况下， 默认使用的是 Nacos 上 Public 这个namespace。如果需要使用自定义的命名空间，可以通过以下配置来实现：
 [source,properties]
 ----
 spring.cloud.nacos.config.namespace=b3404bc0-d7dc-4855-b519-570ed34b62d7
@@ -348,7 +348,13 @@ Nacos Config 目前提供了三种配置能力从 Nacos 拉取相关的配置
 * B: 通过 `spring.cloud.nacos.config.ext-config[n].data-id` 的方式支持多个扩展 Data Id 的配置
 * C: 通过内部相关规则(应用名、应用名+ Profile )自动生成相关的 Data Id 配置
 
-当三种方式共同使用时，他们的一个优先级关系是:A < B < C
+当三种方式共同使用时，他们的一个优先级关系是:
+
+->A为优先级最高的
+
+->B的优先级低于A，
+
+->C的优先级是最低的
 
 === Nacos Config 对外暴露的 Endpoint
 

spring-cloud-alibaba-docs/src/main/asciidoc/rocketmq.adoc

@@ -57,7 +57,7 @@ Send messages:
 sh bin/tools.sh org.apache.rocketmq.example.quickstart.Producer
 ```
 
-Output when the message is successfuly sent: `SendResult [sendStatus=SEND_OK, msgId= ...`
+Output when the message is successfully sent: `SendResult [sendStatus=SEND_OK, msgId= ...`
 
 Receive messages:
 

spring-cloud-alibaba-docs/src/main/asciidoc/schedulerx.adoc

@@ -82,7 +82,7 @@ Job Description： Empty
 Custom Parameters： Empty
 ----
 
-The job above is a “Simple Single-Server Job”, and speficied a Cron expression of "0 * * * * ?" . This means that the job will be executed once and once only in every minute.
+The job above is a “Simple Single-Server Job”, and specified a Cron expression of "0 * * * * ?" . This means that the job will be executed once and once only in every minute.
 
 For more job types, refer to https://help.aliyun.com/document_detail/43136.html[SchedulerX Documentation].
 

spring-cloud-alibaba-examples/sentinel-example/sentinel-dubbo-example/readme-zh.md

@@ -73,7 +73,7 @@ Provider端在application.properties文件中定义dubbo相关的配置，比如
 
 定义具体的服务：
 
-    @Service(
+    @DubboService(
             version = "${foo.service.version}",
             application = "${dubbo.application.id}",
             protocol = "${dubbo.protocol.id}",
@@ -111,7 +111,7 @@ Consumer端在服务调用之前，先定义限流规则。
 
 根据Provider端中发布的定义，使用Dubbo的@Reference注解注入服务对应的Bean：
 
-    @Reference(version = "${foo.service.version}", application = "${dubbo.application.id}",
+    @DubboReference(version = "${foo.service.version}", application = "${dubbo.application.id}",
             path = "dubbo://localhost:12345", timeout = 30000)
 	private FooService fooService;
 

spring-cloud-alibaba-examples/sentinel-example/sentinel-dubbo-example/sentinel-dubbo-consumer-example/src/main/java/com/alibaba/cloud/examples/FooServiceConsumer.java

@@ -16,14 +16,14 @@
 
 package com.alibaba.cloud.examples;
 
-import org.apache.dubbo.config.annotation.Reference;
+import org.apache.dubbo.config.annotation.DubboReference;
 
 /**
  * @author fangjian
  */
 public class FooServiceConsumer {
 
-	@Reference(version = "${foo.service.version}",
+	@DubboReference(version = "${foo.service.version}",
 			application = "${dubbo.application.id}",
 			url = "dubbo://localhost:12345?version=1.0.0", timeout = 30000)
 	private FooService fooService;

spring-cloud-alibaba-examples/sentinel-example/sentinel-dubbo-example/sentinel-dubbo-provider-example/src/main/java/com/alibaba/cloud/examples/FooServiceImpl.java

@@ -16,12 +16,12 @@
 
 package com.alibaba.cloud.examples;
 
-import org.apache.dubbo.config.annotation.Service;
+import org.apache.dubbo.config.annotation.DubboService;
 
 /**
  * @author fangjian
  */
-@Service(version = "${foo.service.version}", application = "${dubbo.application.id}",
+@DubboService(version = "${foo.service.version}", application = "${dubbo.application.id}",
 		protocol = "${dubbo.protocol.id}", registry = "${dubbo.registry.id}")
 public class FooServiceImpl implements FooService {
 

spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/config/DataSourcePropertiesConfiguration.java

@@ -132,7 +132,6 @@ public class DataSourcePropertiesConfiguration {
 				if (!ObjectUtils.isEmpty(field.get(this))) {
 					return field.getName();
 				}
-				return null;
 			}
 			catch (IllegalAccessException e) {
 				// won't happen

spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/converter/SentinelConverter.java

@@ -86,9 +86,8 @@ public abstract class SentinelConverter<T extends Object>
 					});
 
 			for (Object obj : sourceArray) {
-				String item = null;
 				try {
-					item = objectMapper.writeValueAsString(obj);
+					String item = objectMapper.writeValueAsString(obj);
 					Optional.ofNullable(convertRule(item))
 							.ifPresent(convertRule -> ruleCollection.add(convertRule));
 				}

spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/endpoint/NacosConfigHealthIndicator.java

@@ -32,6 +32,16 @@ public class NacosConfigHealthIndicator extends AbstractHealthIndicator {
 
 	private final ConfigService configService;
 
+	/**
+	 * status up .
+	 */
+	private final String STATUS_UP = "UP";
+
+	/**
+	 * status down .
+	 */
+	private final String STATUS_DOWN = "DOWN";
+
 	public NacosConfigHealthIndicator(ConfigService configService) {
 		this.configService = configService;
 	}
@@ -43,10 +53,10 @@ public class NacosConfigHealthIndicator extends AbstractHealthIndicator {
 		// Set the status to Builder
 		builder.status(status);
 		switch (status) {
-		case "UP":
+		case STATUS_UP:
 			builder.up();
 			break;
-		case "DOWN":
+		case STATUS_DOWN:
 			builder.down();
 			break;
 		default:

spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/discovery/actuate/health/NacosDiscoveryHealthIndicator.java

@@ -31,6 +31,16 @@ import org.springframework.boot.actuate.health.HealthIndicator;
  */
 public class NacosDiscoveryHealthIndicator extends AbstractHealthIndicator {
 
+	/**
+	 * status up.
+	 */
+	private static final String STATUS_UP = "UP";
+
+	/**
+	 * status down.
+	 */
+	private static final String STATUS_DOWN = "DOWN";
+
 	private final NamingService namingService;
 
 	public NacosDiscoveryHealthIndicator(NamingService namingService) {
@@ -44,10 +54,10 @@ public class NacosDiscoveryHealthIndicator extends AbstractHealthIndicator {
 		// Set the status to Builder
 		builder.status(status);
 		switch (status) {
-		case "UP":
+		case STATUS_UP:
 			builder.up();
 			break;
-		case "DOWN":
+		case STATUS_DOWN:
 			builder.down();
 			break;
 		default:

spring-cloud-alibaba-starters/spring-cloud-starter-dubbo/src/main/java/com/alibaba/cloud/dubbo/env/DubboCloudProperties.java

@@ -51,6 +51,10 @@ public class DubboCloudProperties {
 
 	private String registryType = DUBBO_CLOUD_REGISTRY_PROPERTY_VALUE;
 
+	private int maxReSubscribeMetadataTimes = 1000;
+
+	private int reSubscribeMetadataIntervial = 5;
+
 	public String getSubscribedServices() {
 		return subscribedServices;
 	}
@@ -91,4 +95,20 @@ public class DubboCloudProperties {
 		this.registryType = registryType;
 	}
 
+	public int getMaxReSubscribeMetadataTimes() {
+		return maxReSubscribeMetadataTimes;
+	}
+
+	public void setMaxReSubscribeMetadataTimes(int maxReSubscribeMetadataTimes) {
+		this.maxReSubscribeMetadataTimes = maxReSubscribeMetadataTimes;
+	}
+
+	public int getReSubscribeMetadataIntervial() {
+		return reSubscribeMetadataIntervial;
+	}
+
+	public void setReSubscribeMetadataIntervial(int reSubscribeMetadataIntervial) {
+		this.reSubscribeMetadataIntervial = reSubscribeMetadataIntervial;
+	}
+
 }

spring-cloud-alibaba-starters/spring-cloud-starter-dubbo/src/main/java/com/alibaba/cloud/dubbo/metadata/repository/DubboServiceMetadataRepository.java

@@ -19,6 +19,7 @@ package com.alibaba.cloud.dubbo.metadata.repository;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -41,6 +42,7 @@ import com.alibaba.cloud.dubbo.util.JSONUtils;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.type.TypeFactory;
 import org.apache.dubbo.common.URL;
+import org.apache.dubbo.common.constants.CommonConstants;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -237,9 +239,6 @@ public class DubboServiceMetadataRepository
 		dispatchEvent(new SubscribedServicesChangedEvent(this, oldSubscribedServices,
 				newSubscribedServices));
 
-		// clear old one, help GC
-		oldSubscribedServices.clear();
-
 		return newSubscribedServices.stream();
 	}
 
@@ -407,9 +406,35 @@ public class DubboServiceMetadataRepository
 
 	public List<URL> getExportedURLs(String serviceInterface, String group,
 			String version) {
+		if (group != null) {
+			List<URL> urls = new LinkedList<>();
+			if (CommonConstants.ANY_VALUE.equals(group)) {
 				String serviceKey = URL.buildKey(serviceInterface, group, version);
+				String expectKey = serviceKey.substring(2);
+				for (String key : allExportedURLs.keySet()) {
+					if (key.endsWith(expectKey)) {
+						urls.addAll(allExportedURLs.get(key));
+					}
+				}
+			}
+			else {
+				String[] groups = group.split(CommonConstants.COMMA_SEPARATOR);
+				for (String expectKey : groups) {
+					String serviceKey = URL.buildKey(serviceInterface, expectKey,
+							version);
+					List<URL> urlList = allExportedURLs.get(serviceKey);
+					if (urlList != null) {
+						urls.addAll(urlList);
+					}
+				}
+			}
+			return urls;
+		}
+		else {
+			String serviceKey = URL.buildKey(serviceInterface, null, version);
 			return allExportedURLs.getOrDefault(serviceKey, Collections.emptyList());
 		}
+	}
 
 	/**
 	 * Initialize the specified service's {@link ServiceRestMetadata}.

spring-cloud-alibaba-starters/spring-cloud-starter-dubbo/src/main/java/com/alibaba/cloud/dubbo/registry/DubboCloudRegistry.java

@@ -23,6 +23,9 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
@@ -45,12 +48,10 @@ import org.springframework.cloud.client.discovery.DiscoveryClient;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.Ordered;
-import org.springframework.core.annotation.Order;
 import org.springframework.util.CollectionUtils;
 
 import static java.lang.String.format;
 import static java.util.Collections.emptyList;
-import static java.util.stream.StreamSupport.stream;
 import static org.apache.dubbo.common.URLBuilder.from;
 import static org.apache.dubbo.common.constants.CommonConstants.GROUP_KEY;
 import static org.apache.dubbo.common.constants.CommonConstants.PID_KEY;
@@ -110,11 +111,23 @@ public class DubboCloudRegistry extends FailbackRegistry {
 
 	private final String currentApplicationName;
 
+	private final Map<URL, NotifyListener> urlNotifyListenerMap = new ConcurrentHashMap<>();
+
+	private final Map<String, ReSubscribeMetadataJob> reConnectJobMap = new ConcurrentHashMap<>();
+
+	private final ScheduledThreadPoolExecutor reConnectPool = new ScheduledThreadPoolExecutor(
+			2);
+
+	private final int maxReSubscribeMetadataTimes;
+
+	private final int reSubscribeMetadataIntervial;
+
 	public DubboCloudRegistry(URL url, DiscoveryClient discoveryClient,
 			DubboServiceMetadataRepository repository,
 			DubboMetadataServiceProxy dubboMetadataConfigServiceProxy,
 			JSONUtils jsonUtils, DubboGenericServiceFactory dubboGenericServiceFactory,
-			ConfigurableApplicationContext applicationContext) {
+			ConfigurableApplicationContext applicationContext,
+			int maxReSubscribeMetadataTimes, int reSubscribeMetadataIntervial) {
 
 		super(url);
 		this.servicesLookupInterval = url
@@ -127,6 +140,11 @@ public class DubboCloudRegistry extends FailbackRegistry {
 		this.applicationContext = applicationContext;
 		this.dubboMetadataUtils = getBean(DubboMetadataUtils.class);
 		this.currentApplicationName = dubboMetadataUtils.getCurrentApplicationName();
+		this.maxReSubscribeMetadataTimes = maxReSubscribeMetadataTimes;
+		this.reSubscribeMetadataIntervial = reSubscribeMetadataIntervial;
+
+		reConnectPool.setKeepAliveTime(10, TimeUnit.MINUTES);
+		reConnectPool.allowCoreThreadTimeOut(true);
 	}
 
 	private <T> T getBean(Class<T> beanClass) {
@@ -177,6 +195,7 @@ public class DubboCloudRegistry extends FailbackRegistry {
 		}
 		else { // for general Dubbo Services
 			subscribeURLs(url, listener);
+			urlNotifyListenerMap.put(url, listener);
 		}
 	}
 
@@ -188,19 +207,34 @@ public class DubboCloudRegistry extends FailbackRegistry {
 		// Async subscription
 		registerServiceInstancesChangedListener(url,
 
-				new ApplicationListener<ServiceInstancesChangedEvent>() {
+				new ServiceInstanceChangeListener() {
-
+
-					private final URL url2subscribe = url;
+					@Override
+					public int getOrder() {
+						return Ordered.LOWEST_PRECEDENCE;
+					}
 
 					@Override
-					@Order
 					public void onApplicationEvent(ServiceInstancesChangedEvent event) {
+
 						Set<String> serviceNames = getServices(url);
 
 						String serviceName = event.getServiceName();
 
 						if (serviceNames.contains(serviceName)) {
+							logger.debug(
+									"handle serviceInstanceChange of general service, serviceName = {}, subscribeUrl={}",
+									event.getServiceName(), url.getServiceKey());
+							try {
 								subscribeURLs(url, serviceNames, listener);
+								reConnectJobMap.remove(serviceName);
+							}
+							catch (Exception e) {
+								logger.warn(String.format(
+										"subscribeURLs failed, serviceName = %s, try reSubscribe again",
+										serviceName), e);
+								addReSubscribeMetadataJob(serviceName, 0);
+							}
 						}
 					}
 
@@ -212,8 +246,19 @@ public class DubboCloudRegistry extends FailbackRegistry {
 				});
 	}
 
-	private void subscribeURLs(URL url, Set<String> serviceNames,
+	void addReSubscribeMetadataJob(String serviceName, int count) {
-			NotifyListener listener) {
+		if (count > maxReSubscribeMetadataTimes) {
+			logger.error(
+					"reSubscribe failed too many times, serviceName = {}, count = {}",
+					serviceName, count);
+			return;
+		}
+		ReSubscribeMetadataJob job = new ReSubscribeMetadataJob(serviceName, this, count);
+		reConnectJobMap.put(serviceName, job);
+		reConnectPool.schedule(job, reSubscribeMetadataIntervial, TimeUnit.SECONDS);
+	}
+
+	void subscribeURLs(URL url, Set<String> serviceNames, NotifyListener listener) {
 
 		List<URL> subscribedURLs = new LinkedList<>();
 
@@ -252,6 +297,10 @@ public class DubboCloudRegistry extends FailbackRegistry {
 						serviceName));
 			}
 		}
+		else {
+			logger.debug("subscribe from serviceName = {}, size = {}", serviceName,
+					serviceInstances.size());
+		}
 
 		List<URL> exportedURLs = getExportedURLs(subscribedURL, serviceName,
 				serviceInstances);
@@ -389,7 +438,7 @@ public class DubboCloudRegistry extends FailbackRegistry {
 		return metadata.containsKey(METADATA_SERVICE_URLS_PROPERTY_NAME);
 	}
 
-	private Set<String> getServices(URL url) {
+	Set<String> getServices(URL url) {
 		Set<String> subscribedServices = repository.getSubscribedServices();
 		// TODO Add the filter feature
 		return subscribedServices;
@@ -419,11 +468,6 @@ public class DubboCloudRegistry extends FailbackRegistry {
 		listener.notify(subscribedURLs);
 	}
 
-	private List<ServiceInstance> getServiceInstances(Iterable<String> serviceNames) {
-		return stream(serviceNames.spliterator(), false).map(this::getServiceInstances)
-				.flatMap(Collection::stream).collect(Collectors.toList());
-	}
-
 	private List<ServiceInstance> getServiceInstances(String serviceName) {
 		return hasText(serviceName) ? doGetServiceInstances(serviceName) : emptyList();
 	}
@@ -471,27 +515,38 @@ public class DubboCloudRegistry extends FailbackRegistry {
 	private void subscribeDubboMetadataServiceURLs(URL subscribedURL,
 			NotifyListener listener) {
 
-		// Sync subscription
 		subscribeDubboMetadataServiceURLs(subscribedURL, listener,
 				getServiceName(subscribedURL));
 
 		// Sync subscription
 		if (containsProviderCategory(subscribedURL)) {
-			registerServiceInstancesChangedListener(subscribedURL,
-					new ApplicationListener<ServiceInstancesChangedEvent>() {
 
-						private final URL url2subscribe = subscribedURL;
+			registerServiceInstancesChangedListener(subscribedURL,
+					new ServiceInstanceChangeListener() {
+
+						@Override
+						public int getOrder() {
+							return Ordered.LOWEST_PRECEDENCE - 1;
+						}
 
 						@Override
-						@Order(Ordered.LOWEST_PRECEDENCE - 1)
 						public void onApplicationEvent(
 								ServiceInstancesChangedEvent event) {
 							String sourceServiceName = event.getServiceName();
+							List<ServiceInstance> serviceInstances = event
+									.getServiceInstances();
 							String serviceName = getServiceName(subscribedURL);
 
 							if (Objects.equals(sourceServiceName, serviceName)) {
+								logger.debug(
+										"handle serviceInstanceChange of metadata service, serviceName = {}, subscribeUrl={}",
+										event.getServiceName(),
+										subscribedURL.getServiceKey());
+
+								// only update serviceInstances of the specified
+								// serviceName
 								subscribeDubboMetadataServiceURLs(subscribedURL, listener,
-										sourceServiceName);
+										sourceServiceName, serviceInstances);
 							}
 						}
 
@@ -509,34 +564,25 @@ public class DubboCloudRegistry extends FailbackRegistry {
 	}
 
 	private void subscribeDubboMetadataServiceURLs(URL subscribedURL,
-			NotifyListener listener, String serviceName) {
+			NotifyListener listener, String serviceName,
+			List<ServiceInstance> serviceInstances) {
 
 		String serviceInterface = subscribedURL.getServiceInterface();
 		String version = subscribedURL.getParameter(VERSION_KEY);
 		String protocol = subscribedURL.getParameter(PROTOCOL_KEY);
 
-		List<ServiceInstance> serviceInstances = getServiceInstances(serviceName);
-
 		List<URL> urls = dubboMetadataUtils.getDubboMetadataServiceURLs(serviceInstances,
 				serviceInterface, version, protocol);
 
 		notifyAllSubscribedURLs(subscribedURL, urls, listener);
 	}
 
-	// private void subscribeDubboMetadataServiceURLs(URL subscribedURL,
+	private void subscribeDubboMetadataServiceURLs(URL subscribedURL,
-	// NotifyListener listener, Set<String> serviceNames) {
+			NotifyListener listener, String serviceName) {
-	//
+		List<ServiceInstance> serviceInstances = getServiceInstances(serviceName);
-	// String serviceInterface = subscribedURL.getServiceInterface();
+		subscribeDubboMetadataServiceURLs(subscribedURL, listener, serviceName,
-	// String version = subscribedURL.getParameter(VERSION_KEY);
+				serviceInstances);
-	// String protocol = subscribedURL.getParameter(PROTOCOL_KEY);
+	}
-	//
-	// List<ServiceInstance> serviceInstances = getServiceInstances(serviceNames);
-	//
-	// List<URL> urls = dubboMetadataUtils.getDubboMetadataServiceURLs(serviceInstances,
-	// serviceInterface, version, protocol);
-	//
-	// notifyAllSubscribedURLs(subscribedURL, urls, listener);
-	// }
 
 	private boolean containsProviderCategory(URL subscribedURL) {
 		String category = subscribedURL.getParameter(CATEGORY_KEY);
@@ -557,6 +603,14 @@ public class DubboCloudRegistry extends FailbackRegistry {
 		return ADMIN_PROTOCOL.equals(url.getProtocol());
 	}
 
+	public Map<URL, NotifyListener> getUrlNotifyListenerMap() {
+		return urlNotifyListenerMap;
+	}
+
+	public Map<String, ReSubscribeMetadataJob> getReConnectJobMap() {
+		return reConnectJobMap;
+	}
+
 	protected boolean isDubboMetadataServiceURL(URL url) {
 		return DUBBO_METADATA_SERVICE_CLASS_NAME.equals(url.getServiceInterface());
 	}

spring-cloud-alibaba-starters/spring-cloud-starter-dubbo/src/main/java/com/alibaba/cloud/dubbo/registry/ReSubscribeMetadataJob.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2013-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.alibaba.cloud.dubbo.registry;
+
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.dubbo.common.URL;
+import org.apache.dubbo.registry.NotifyListener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * For re subscribe URL from provider.
+ *
+ * @author <a href="mailto:chenxilzx1@gmail.com">theonefx</a>
+ */
+public class ReSubscribeMetadataJob implements Runnable {
+
+	protected final Logger logger = LoggerFactory.getLogger(ReSubscribeMetadataJob.class);
+
+	private final String serviceName;
+
+	private final DubboCloudRegistry dubboCloudRegistry;
+
+	private final int errorCounts;
+
+	public ReSubscribeMetadataJob(String serviceName,
+			DubboCloudRegistry dubboCloudRegistry, int errorCounts) {
+		this.errorCounts = errorCounts;
+		this.serviceName = serviceName;
+		this.dubboCloudRegistry = dubboCloudRegistry;
+	}
+
+	public ReSubscribeMetadataJob(String serviceName,
+			DubboCloudRegistry dubboCloudRegistry) {
+		this(serviceName, dubboCloudRegistry, 0);
+	}
+
+	@Override
+	public void run() {
+		if (dubboCloudRegistry.getReConnectJobMap().get(serviceName) != this) {
+			return;
+		}
+		try {
+			logger.info("reSubscribe, serviceName = {}, count = {}", serviceName,
+					errorCounts);
+			for (Map.Entry<URL, NotifyListener> entry : dubboCloudRegistry
+					.getUrlNotifyListenerMap().entrySet()) {
+				doRun(entry.getKey(), entry.getValue());
+			}
+			dubboCloudRegistry.getReConnectJobMap().remove(serviceName);
+		}
+		catch (Exception e) {
+			logger.warn(String.format(
+					"reSubscribe failed, serviceName = %s, try refresh again",
+					serviceName), e);
+			dubboCloudRegistry.addReSubscribeMetadataJob(serviceName, errorCounts + 1);
+		}
+	}
+
+	private void doRun(URL url, NotifyListener listener) {
+		Set<String> serviceNames = dubboCloudRegistry.getServices(url);
+
+		if (serviceNames.contains(serviceName)) {
+			dubboCloudRegistry.subscribeURLs(url, serviceNames, listener);
+		}
+	}
+
+}

spring-cloud-alibaba-starters/spring-cloud-starter-dubbo/src/main/java/com/alibaba/cloud/dubbo/registry/ServiceInstanceChangeListener.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2013-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.alibaba.cloud.dubbo.registry;
+
+import com.alibaba.cloud.dubbo.registry.event.ServiceInstancesChangedEvent;
+
+import org.springframework.context.ApplicationListener;
+import org.springframework.core.Ordered;
+
+/**
+ * The interface of ServiceInstanceChange event Listener.
+ *
+ * @author <a href="mailto:chenxilzx1@gmail.com">theonefx</a>
+ * @see ServiceInstancesChangedEvent
+ * @see Ordered
+ * @see ApplicationListener
+ */
+public interface ServiceInstanceChangeListener
+		extends ApplicationListener<ServiceInstancesChangedEvent>, Ordered {
+
+}

spring-cloud-alibaba-starters/spring-cloud-starter-dubbo/src/main/java/com/alibaba/cloud/dubbo/registry/SpringCloudRegistryFactory.java

@@ -100,7 +100,9 @@ public class SpringCloudRegistryFactory extends AbstractRegistryFactory {
 		default:
 			registry = new DubboCloudRegistry(url, discoveryClient,
 					dubboServiceMetadataRepository, dubboMetadataConfigServiceProxy,
-					jsonUtils, dubboGenericServiceFactory, applicationContext);
+					jsonUtils, dubboGenericServiceFactory, applicationContext,
+					dubboCloudProperties.getMaxReSubscribeMetadataTimes(),
+					dubboCloudProperties.getReSubscribeMetadataIntervial());
 			break;
 		}