这个issue就是我这前写了那两篇文章的那个issue

Dubbo重启服务提供者或先启动服务消费者后启动服务提供者，消费者有时候会出现找不到服务的问题及解决

https://mp.weixin.qq.com/s/L-ejXtV9wk-hPYAc2e3jvQ

https://mp.weixin.qq.com/s/-9t0tqnVX-A2fz4SNiPFdA

1.官方信息

Spring Cloud Dubbo组件去留问题讨论 #2398

https://github.com/alibaba/spring-cloud-alibaba/issues/2398

官方issue1805

https://github.com/alibaba/spring-cloud-alibaba/issues/1805

官方issue1805提交

https://github.com/alibaba/spring-cloud-alibaba/commit/fd8a6a6f6c262cbf8d20c049c84cd445651bd969

2.版本代码对比

Spring-Cloud-Start-dubbo-2.2.6-RELEASE的服务注册自动配置类如下：

/* * 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.autoconfigure;
import java.util.Collection;import java.util.HashSet;import java.util.Iterator;import java.util.List;import java.util.Map;import java.util.Set;import java.util.concurrent.ConcurrentHashMap;
import com.alibaba.cloud.dubbo.autoconfigure.condition.MissingSpringCloudRegistryConfigPropertyCondition;import com.alibaba.cloud.dubbo.bootstrap.DubboBootstrapStartCommandLineRunner;import com.alibaba.cloud.dubbo.bootstrap.DubboBootstrapWrapper;import com.alibaba.cloud.dubbo.bootstrap.event.DubboBootstrapStartedEvent;import com.alibaba.cloud.dubbo.metadata.repository.DubboServiceMetadataRepository;import com.alibaba.cloud.dubbo.registry.DubboServiceRegistrationEventPublishingAspect;import com.alibaba.cloud.dubbo.registry.event.ServiceInstancePreDeregisteredEvent;import com.alibaba.cloud.dubbo.registry.event.ServiceInstancePreRegisteredEvent;import com.ecwid.consul.v1.agent.model.NewService;import com.netflix.appinfo.InstanceInfo;import org.apache.dubbo.config.RegistryConfig;import org.apache.dubbo.config.bootstrap.DubboBootstrap;import org.apache.dubbo.config.spring.ServiceBean;import org.slf4j.Logger;import org.slf4j.LoggerFactory;
import org.springframework.aop.support.AopUtils;import org.springframework.beans.factory.ObjectProvider;import org.springframework.beans.factory.SmartInitializingSingleton;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.autoconfigure.AutoConfigureAfter;import org.springframework.boot.autoconfigure.AutoConfigureOrder;import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;import org.springframework.cloud.client.ServiceInstance;import org.springframework.cloud.client.serviceregistry.Registration;import org.springframework.cloud.client.serviceregistry.ServiceRegistry;import org.springframework.cloud.consul.discovery.ConsulDiscoveryProperties;import org.springframework.cloud.consul.serviceregistry.ConsulRegistration;import org.springframework.cloud.netflix.eureka.EurekaInstanceConfigBean;import org.springframework.cloud.netflix.eureka.serviceregistry.EurekaAutoServiceRegistration;import org.springframework.cloud.netflix.eureka.serviceregistry.EurekaRegistration;import org.springframework.cloud.netflix.eureka.serviceregistry.EurekaServiceRegistry;import org.springframework.context.SmartLifecycle;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Conditional;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Import;import org.springframework.context.event.EventListener;import org.springframework.util.StringUtils;
import static com.alibaba.cloud.dubbo.autoconfigure.DubboServiceRegistrationAutoConfiguration.CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME;import static com.alibaba.cloud.dubbo.autoconfigure.DubboServiceRegistrationAutoConfiguration.EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME;import static com.alibaba.cloud.dubbo.registry.SpringCloudRegistryFactory.ADDRESS;import static com.alibaba.cloud.dubbo.registry.SpringCloudRegistryFactory.PROTOCOL;import static org.springframework.util.ObjectUtils.isEmpty;
/** * Dubbo Service Registration Auto-{@link Configuration}. * * @author Mercy * @author theonefx */@Configuration(proxyBeanMethods = false)@Import({ DubboServiceRegistrationEventPublishingAspect.class,    DubboBootstrapStartCommandLineRunner.class })@ConditionalOnProperty(value = "spring.cloud.service-registry.auto-registration.enabled",    matchIfMissing = true)@AutoConfigureAfter(name = { EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME,    CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME,    "org.springframework.cloud.client.serviceregistry.AutoServiceRegistrationAutoConfiguration" },    value = { DubboMetadataAutoConfiguration.class })public class DubboServiceRegistrationAutoConfiguration {
  /**   * EurekaClientAutoConfiguration.   */  public static final String EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME = "org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration";
  /**   * ConsulAutoServiceRegistrationAutoConfiguration.   */  public static final String CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME = "org.springframework.cloud.consul.serviceregistry.ConsulAutoServiceRegistrationAutoConfiguration";
  /**   * ConsulAutoRegistration.   */  public static final String CONSUL_AUTO_SERVICE_AUTO_REGISTRATION_CLASS_NAME = "org.springframework.cloud.consul.serviceregistry.ConsulAutoRegistration";
  /**   * ZookeeperAutoServiceRegistrationAutoConfiguration.   */  public static final String ZOOKEEPER_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME = "org.springframework.cloud.zookeeper.serviceregistry.ZookeeperAutoServiceRegistrationAutoConfiguration";
  private static final Logger logger = LoggerFactory      .getLogger(DubboServiceRegistrationAutoConfiguration.class);
  @Autowired  private DubboServiceMetadataRepository dubboServiceMetadataRepository;
  @Bean  @Conditional({ MissingSpringCloudRegistryConfigPropertyCondition.class })  public RegistryConfig defaultSpringCloudRegistryConfig() {    return new RegistryConfig(ADDRESS, PROTOCOL);  }
  private Map, Set> registrations = new ConcurrentHashMap<>();
  @EventListener(DubboBootstrapStartedEvent.class)  public void onDubboBootstrapStarted(DubboBootstrapStartedEvent event) {    if (!event.getSource().isReady()) {      return;    }    registrations.forEach(        (registry, registrations) -> registrations.forEach(registration -> {          attachDubboMetadataServiceMetadata(registration);          registry.register(registration);        }));  }
  @EventListener(ServiceInstancePreRegisteredEvent.class)  public void onServiceInstancePreRegistered(ServiceInstancePreRegisteredEvent event) {    Registration registration = event.getSource();    if (!DubboBootstrap.getInstance().isReady()        || !DubboBootstrap.getInstance().isStarted()) {      ServiceRegistry registry = event.getRegistry();      synchronized (registry) {        registrations.putIfAbsent(registry, new HashSet<>());        registrations.get(registry).add(registration);      }    }    else {      attachDubboMetadataServiceMetadata(registration);    }
  }
  @EventListener(ServiceInstancePreDeregisteredEvent.class)  public void onServiceInstancePreDeregistered(      ServiceInstancePreDeregisteredEvent event) {    ServiceRegistry registry = event.getRegistry();    registrations.remove(registry);  }
  private void attachDubboMetadataServiceMetadata(Registration registration) {    if (registration == null) {      return;    }    synchronized (registration) {      Map metadata = registration.getMetadata();      attachDubboMetadataServiceMetadata(metadata);    }  }
  private void attachDubboMetadataServiceMetadata(Map metadata) {    Map serviceMetadata = dubboServiceMetadataRepository        .getDubboMetadataServiceMetadata();    if (!isEmpty(serviceMetadata)) {      metadata.putAll(serviceMetadata);    }  }
  @Configuration(proxyBeanMethods = false)  @ConditionalOnBean(name = EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME)  class EurekaConfiguration implements SmartInitializingSingleton {
    @Autowired    private ObjectProvider> serviceBeans;
    @EventListener(DubboBootstrapStartedEvent.class)    public void onDubboBootstrapStarted(DubboBootstrapStartedEvent event) {      DubboBootstrapWrapper wrapper = event.getSource();      if (!wrapper.isReady()) {        return;      }      registrations.forEach(          (registry, registrations) -> registrations.removeIf(registration -> {            if (!(registration instanceof EurekaRegistration)) {              return false;            }            EurekaRegistration eurekaRegistration = (EurekaRegistration) registration;            InstanceInfo instanceInfo = eurekaRegistration                .getApplicationInfoManager().getInfo();
            EurekaInstanceConfigBean config = (EurekaInstanceConfigBean) eurekaRegistration                .getInstanceConfig();            config.setInitialStatus(InstanceInfo.InstanceStatus.UP);
            attachDubboMetadataServiceMetadata(instanceInfo.getMetadata());            eurekaRegistration.getApplicationInfoManager()                .registerAppMetadata(instanceInfo.getMetadata());            eurekaRegistration.getApplicationInfoManager()                .setInstanceStatus(InstanceInfo.InstanceStatus.UP);            return true;          }));    }
    @EventListener(ServiceInstancePreRegisteredEvent.class)    public void onServiceInstancePreRegistered(        ServiceInstancePreRegisteredEvent event) {      Registration registration = event.getSource();      if (!(registration instanceof EurekaRegistration)) {        return;      }
      if (DubboBootstrap.getInstance().isReady()          && DubboBootstrap.getInstance().isStarted()) {        EurekaRegistration eurekaRegistration = (EurekaRegistration) registration;        InstanceInfo instanceInfo = eurekaRegistration.getApplicationInfoManager()            .getInfo();
        EurekaInstanceConfigBean config = (EurekaInstanceConfigBean) eurekaRegistration            .getInstanceConfig();        config.setInitialStatus(InstanceInfo.InstanceStatus.UP);
        attachDubboMetadataServiceMetadata(instanceInfo.getMetadata());        eurekaRegistration.getApplicationInfoManager()            .registerAppMetadata(instanceInfo.getMetadata());      }      else {        EurekaRegistration eurekaRegistration = (EurekaRegistration) registration;        EurekaInstanceConfigBean config = (EurekaInstanceConfigBean) eurekaRegistration            .getInstanceConfig();        config.setInitialStatus(InstanceInfo.InstanceStatus.STARTING);      }    }
    /**     * {@link EurekaServiceRegistry} will register current {@link ServiceInstance     * service instance} on {@link EurekaAutoServiceRegistration#start()} execution(in     * {@link SmartLifecycle#start() start phase}), thus this method must     * {@link ServiceBean#export() export} all {@link ServiceBean ServiceBeans} in     * advance.     */    @Override    public void afterSingletonsInstantiated() {      Collection serviceBeans = this.serviceBeans.getIfAvailable();      if (!isEmpty(serviceBeans)) {        serviceBeans.forEach(ServiceBean::export);      }    }
  }
  @Configuration(proxyBeanMethods = false)  @ConditionalOnBean(name = CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME)  @AutoConfigureOrder  class ConsulConfiguration {
    @Autowired    private ConsulDiscoveryProperties consulDiscoveryProperties;
    @EventListener(DubboBootstrapStartedEvent.class)    public void attachURLsIntoMetadataBeforeReRegist(        DubboBootstrapStartedEvent event) {      if (!event.getSource().isReady()) {        return;      }      registrations.entrySet().removeIf(entry -> {        Set registrations = entry.getValue();        registrations.removeIf(registration -> {          Class registrationClass = AopUtils.getTargetClass(registration);          String registrationClassName = registrationClass.getName();          return !CONSUL_AUTO_SERVICE_AUTO_REGISTRATION_CLASS_NAME              .equalsIgnoreCase(registrationClassName);        });        return registrations.isEmpty();      });
      registrations.forEach(          (registry, registrations) -> registrations.forEach(registration -> {            ConsulRegistration consulRegistration = (ConsulRegistration) registration;            attachURLsIntoMetadata(consulRegistration);          }));    }
    @EventListener(ServiceInstancePreRegisteredEvent.class)    public void onServiceInstancePreRegistered(        ServiceInstancePreRegisteredEvent event) {      Registration registration = event.getSource();      attachURLsIntoMetadata((ConsulRegistration) registration);    }
    private void attachURLsIntoMetadata(ConsulRegistration consulRegistration) {      Map serviceMetadata = dubboServiceMetadataRepository          .getDubboMetadataServiceMetadata();      if (isEmpty(serviceMetadata)) {        return;      }      NewService newService = consulRegistration.getService();      if (consulDiscoveryProperties.isTagsAsMetadata()) {        for (Map.Entry entry : serviceMetadata.entrySet()) {          attAsTag(newService.getTags(), entry.getKey(), entry.getValue());        }      }      else {        newService.getMeta().putAll(serviceMetadata);      }    }
    private void attAsTag(List tags, String key, String value) {      Iterator iter = tags.iterator();      while (iter.hasNext()) {        String tag = iter.next();        String[] tmp = tag.split("=");        if (StringUtils.pathEquals(tmp[0], key)) {          iter.remove();        }      }      tags.add(key + "=" + value);    }
  }
}

DubboServiceRegistrationEventPublishingAspect类：

/* * 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.ServiceInstancePreDeregisteredEvent;import com.alibaba.cloud.dubbo.registry.event.ServiceInstancePreRegisteredEvent;import com.alibaba.cloud.dubbo.registry.event.ServiceInstanceRegisteredEvent;import org.aspectj.lang.annotation.After;import org.aspectj.lang.annotation.Aspect;import org.aspectj.lang.annotation.Before;
import org.springframework.cloud.client.serviceregistry.Registration;import org.springframework.cloud.client.serviceregistry.ServiceRegistry;import org.springframework.context.ApplicationEventPublisher;import org.springframework.context.ApplicationEventPublisherAware;
/** * Dubbo Service Registration Event-Publishing Aspect. * * @author Mercy * @see ServiceInstancePreRegisteredEvent * @see ServiceInstanceRegisteredEvent * @see ServiceInstancePreDeregisteredEvent */@Aspectpublic class DubboServiceRegistrationEventPublishingAspect    implements ApplicationEventPublisherAware {
  /**   * The pointcut expression for {@link ServiceRegistry#register(Registration)}.   */  public static final String REGISTER_POINTCUT_EXPRESSION = "execution(* org.springframework.cloud.client.serviceregistry.ServiceRegistry.register(*)) && target(registry) && args(registration)";
  /**   * The pointcut expression for {@link ServiceRegistry#deregister(Registration)}.   */  public static final String DEREGISTER_POINTCUT_EXPRESSION = "execution(* org.springframework.cloud.client.serviceregistry.ServiceRegistry.deregister(*)) && target(registry) && args(registration)";
  private ApplicationEventPublisher applicationEventPublisher;
  @Before(value = REGISTER_POINTCUT_EXPRESSION, argNames = "registry, registration")  public void beforeRegister(ServiceRegistry registry, Registration registration) {    applicationEventPublisher.publishEvent(        new ServiceInstancePreRegisteredEvent(registry, registration));  }
  @Before(value = DEREGISTER_POINTCUT_EXPRESSION, argNames = "registry, registration")  public void beforeDeregister(ServiceRegistry registry, Registration registration) {    applicationEventPublisher.publishEvent(        new ServiceInstancePreDeregisteredEvent(registry, registration));  }
  @After(value = REGISTER_POINTCUT_EXPRESSION, argNames = "registry, registration")  public void afterRegister(ServiceRegistry registry, Registration registration) {    applicationEventPublisher        .publishEvent(new ServiceInstanceRegisteredEvent(registration));  }
  @Override  public void setApplicationEventPublisher(      ApplicationEventPublisher applicationEventPublisher) {    this.applicationEventPublisher = applicationEventPublisher;  }
}

spring-cloud-alibaba-2022.0.0.0

https://github.com/alibaba/spring-cloud-alibaba/tree/fd8a6a6f6c262cbf8d20c049c84cd445651bd969

Spring-Cloud-Start-dubbo-2.2.7-RELEASE的服务注册自动配置类如下：

ApplicationContextEvent是一个抽象类：在容器启动、刷新、关闭和停止的时候都会发送这个事件。

/* * 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.autoconfigure;
import java.util.Collection;import java.util.HashSet;import java.util.List;import java.util.Map;import java.util.Set;import java.util.concurrent.ConcurrentHashMap;
import com.alibaba.cloud.dubbo.autoconfigure.condition.MissingSpringCloudRegistryConfigPropertyCondition;import com.alibaba.cloud.dubbo.metadata.repository.DubboServiceMetadataRepository;import com.alibaba.cloud.dubbo.registry.DubboServiceRegistrationEventPublishingAspect;import com.alibaba.cloud.dubbo.registry.event.ServiceInstancePreDeregisteredEvent;import com.alibaba.cloud.dubbo.registry.event.ServiceInstancePreRegisteredEvent;import com.ecwid.consul.v1.agent.model.NewService;import com.netflix.appinfo.InstanceInfo;import org.apache.dubbo.config.RegistryConfig;import org.apache.dubbo.config.spring.ServiceBean;import org.slf4j.Logger;import org.slf4j.LoggerFactory;
import org.springframework.aop.support.AopUtils;import org.springframework.beans.factory.ObjectProvider;import org.springframework.beans.factory.SmartInitializingSingleton;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.autoconfigure.AutoConfigureAfter;import org.springframework.boot.autoconfigure.AutoConfigureOrder;import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;import org.springframework.cloud.client.ServiceInstance;import org.springframework.cloud.client.serviceregistry.Registration;import org.springframework.cloud.client.serviceregistry.ServiceRegistry;import org.springframework.cloud.consul.serviceregistry.ConsulRegistration;import org.springframework.cloud.netflix.eureka.serviceregistry.EurekaAutoServiceRegistration;import org.springframework.cloud.netflix.eureka.serviceregistry.EurekaRegistration;import org.springframework.cloud.netflix.eureka.serviceregistry.EurekaServiceRegistry;import org.springframework.context.SmartLifecycle;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Conditional;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Import;import org.springframework.context.event.ApplicationContextEvent;import org.springframework.context.event.EventListener;import org.springframework.core.Ordered;import org.springframework.core.annotation.Order;
import static com.alibaba.cloud.dubbo.autoconfigure.DubboServiceRegistrationAutoConfiguration.CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME;import static com.alibaba.cloud.dubbo.autoconfigure.DubboServiceRegistrationAutoConfiguration.EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME;import static com.alibaba.cloud.dubbo.registry.SpringCloudRegistryFactory.ADDRESS;import static com.alibaba.cloud.dubbo.registry.SpringCloudRegistryFactory.PROTOCOL;import static org.springframework.util.ObjectUtils.isEmpty;
/** * Dubbo Service Registration Auto-{@link Configuration}. * * @author Mercy */@Configuration(proxyBeanMethods = false)@Import({ DubboServiceRegistrationEventPublishingAspect.class })@ConditionalOnProperty(value = "spring.cloud.service-registry.auto-registration.enabled",    matchIfMissing = true)@AutoConfigureAfter(name = { EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME,    CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME,    "org.springframework.cloud.client.serviceregistry.AutoServiceRegistrationAutoConfiguration" },    value = { DubboMetadataAutoConfiguration.class })public class DubboServiceRegistrationAutoConfiguration {
  /**   * EurekaClientAutoConfiguration.   */  public static final String EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME = "org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration";
  /**   * ConsulAutoServiceRegistrationAutoConfiguration.   */  public static final String CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME = "org.springframework.cloud.consul.serviceregistry.ConsulAutoServiceRegistrationAutoConfiguration";
  /**   * ConsulAutoRegistration.   */  public static final String CONSUL_AUTO_SERVICE_AUTO_REGISTRATION_CLASS_NAME = "org.springframework.cloud.consul.serviceregistry.ConsulAutoRegistration";
  /**   * ZookeeperAutoServiceRegistrationAutoConfiguration.   */  public static final String ZOOKEEPER_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME = "org.springframework.cloud.zookeeper.serviceregistry.ZookeeperAutoServiceRegistrationAutoConfiguration";
  private static final Logger logger = LoggerFactory      .getLogger(DubboServiceRegistrationAutoConfiguration.class);
  @Autowired  private DubboServiceMetadataRepository dubboServiceMetadataRepository;
  @Bean  @Conditional({ MissingSpringCloudRegistryConfigPropertyCondition.class })  public RegistryConfig defaultSpringCloudRegistryConfig() {    return new RegistryConfig(ADDRESS, PROTOCOL);  }
  private Map, Set> registrations = new ConcurrentHashMap<>();
    // 监听ApplicationContextEvent这个事件重新注册dubbo的服务  @Order  @EventListener(ApplicationContextEvent.class)  public void attachDubboMetadataAndRegistAgain(ApplicationContextEvent event) {    registrations.forEach(        (registry, registrations) -> registrations.forEach(registration -> {          attachDubboMetadataServiceMetadata(registration);          registry.register(registration);        }));  }   //dubbo的aspect切拦截nacos服务注册前会发送这个事件，监听到该事件后需要将注册到nacos的服务加入到registrations  @EventListener(ServiceInstancePreRegisteredEvent.class)  public void onServiceInstancePreRegistered(ServiceInstancePreRegisteredEvent event) {    Registration registration = event.getSource();    ServiceRegistry registry = event.getRegistry();        // 这里加了一个jvm的锁    synchronized (registry) {      registrations.putIfAbsent(registry, new HashSet<>());      registrations.get(registry).add(registration);    }  }        //dubbo的aspect切面拦截服务取消注册前会发送这个时间，监听到该事件后需要将服务注册信息从registrations中移除  @EventListener(ServiceInstancePreDeregisteredEvent.class)  public void onServiceInstancePreDeregistered(      ServiceInstancePreDeregisteredEvent event) {    ServiceRegistry registry = event.getRegistry();    registrations.remove(registry);  }
  private void attachDubboMetadataServiceMetadata(Registration registration) {    if (registration == null) {      return;    }    synchronized (registration) {      Map metadata = registration.getMetadata();      attachDubboMetadataServiceMetadata(metadata);    }  }    //这里是dubbo服务元数据,会加入到一个map集合中，然后会走服务变更，通知服务订阅者重新拉取最新的注册的服务信息(猜测)。  private void attachDubboMetadataServiceMetadata(Map metadata) {    Map serviceMetadata = dubboServiceMetadataRepository        .getDubboMetadataServiceMetadata();    if (!isEmpty(serviceMetadata)) {      metadata.putAll(serviceMetadata);    }  }
  @Configuration(proxyBeanMethods = false)  @ConditionalOnBean(name = EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME)  class EurekaConfiguration implements SmartInitializingSingleton {
    @Autowired    private ObjectProvider> serviceBeans;
    @Order(Ordered.LOWEST_PRECEDENCE - 1)    @EventListener(ApplicationContextEvent.class)    public void onServiceInstancePreRegistered(ApplicationContextEvent event) {      registrations.forEach((registry, registrations)-> registrations.forEach(registration -> {        EurekaRegistration eurekaRegistration = (EurekaRegistration) registration;        InstanceInfo instanceInfo = eurekaRegistration.getApplicationInfoManager().getInfo();        attachDubboMetadataServiceMetadata(instanceInfo.getMetadata());      }));    }
    /**     * {@link EurekaServiceRegistry} will register current {@link ServiceInstance     * service instance} on {@link EurekaAutoServiceRegistration#start()} execution(in     * {@link SmartLifecycle#start() start phase}), thus this method must     * {@link ServiceBean#export() export} all {@link ServiceBean ServiceBeans} in     * advance.     */    @Override    public void afterSingletonsInstantiated() {      Collection serviceBeans = this.serviceBeans.getIfAvailable();      if (!isEmpty(serviceBeans)) {        serviceBeans.forEach(ServiceBean::export);      }    }
  }
  @Configuration(proxyBeanMethods = false)  @ConditionalOnBean(name = CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME)  @AutoConfigureOrder  class ConsulConfiguration {
    @Order(Ordered.LOWEST_PRECEDENCE - 1)    @EventListener(ApplicationContextEvent.class)    public void attachURLsIntoMetadataBeforeReRegist(ApplicationContextEvent event) {      registrations.entrySet().removeIf(entry -> {        Set registrations = entry.getValue();        registrations.removeIf(registration -> {          Class registrationClass = AopUtils.getTargetClass(registration);          String registrationClassName = registrationClass.getName();          return !CONSUL_AUTO_SERVICE_AUTO_REGISTRATION_CLASS_NAME              .equalsIgnoreCase(registrationClassName);        });        return registrations.isEmpty();      });
      registrations.forEach(          (registry, registrations) -> registrations.forEach(registration -> {            ConsulRegistration consulRegistration = (ConsulRegistration) registration;            attachURLsIntoMetadata(consulRegistration);          }));    }
    private void attachURLsIntoMetadata(ConsulRegistration consulRegistration) {      NewService newService = consulRegistration.getService();      Map serviceMetadata = dubboServiceMetadataRepository          .getDubboMetadataServiceMetadata();      if (!isEmpty(serviceMetadata)) {        List tags = newService.getTags();        for (Map.Entry entry : serviceMetadata.entrySet()) {          tags.add(entry.getKey() + "=" + entry.getValue());        }      }    }
  }
}

说明：

将2022.0.0.0的start的服务注册自动装配类扣出来，放到项目中，然后注释EurekaConfiguration和ConsulConfiguration的自动装配即可，如果要用可以把先关的包引入进来，这个版本的start和2.2.7版本的这个start相差不大，可以替换使用

之前通过升级解决这个问题，估计是巧合吧Duboo项目集成升级问题解决,百思不得其解，然后我就去git的官网上看了下找到了这个issue,然后官方是在spring-cloud-alibaba-2022.0.0.0这个版本才修复有提交代码记录的，由于这个版本所需要的版本如下：

我们项目中的springBoot的版本是2.3.12.RELEASE，所以都不想升级版本依赖，所以想了这个办法，直接将这个类抠出来用下就可以了。

3.修改尝试

package com.alibaba.cloud.dubbo.autoconfigure;
/* * 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. */
import com.alibaba.cloud.dubbo.autoconfigure.condition.MissingSpringCloudRegistryConfigPropertyCondition;import com.alibaba.cloud.dubbo.metadata.repository.DubboServiceMetadataRepository;import com.alibaba.cloud.dubbo.registry.DubboServiceRegistrationEventPublishingAspect;import com.alibaba.cloud.dubbo.registry.event.ServiceInstancePreDeregisteredEvent;import com.alibaba.cloud.dubbo.registry.event.ServiceInstancePreRegisteredEvent;import org.apache.dubbo.config.RegistryConfig;import org.apache.dubbo.config.spring.ServiceBean;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.autoconfigure.AutoConfigureAfter;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;import org.springframework.cloud.client.ServiceInstance;import org.springframework.cloud.client.serviceregistry.Registration;import org.springframework.cloud.client.serviceregistry.ServiceRegistry;import org.springframework.context.SmartLifecycle;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Conditional;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Import;import org.springframework.context.event.ApplicationContextEvent;import org.springframework.context.event.EventListener;import org.springframework.core.annotation.Order;
import java.util.HashSet;import java.util.Map;import java.util.Set;import java.util.concurrent.ConcurrentHashMap;
import static com.alibaba.cloud.dubbo.autoconfigure.DubboServiceRegistrationAutoConfiguration.CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME;import static com.alibaba.cloud.dubbo.autoconfigure.DubboServiceRegistrationAutoConfiguration.EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME;import static com.alibaba.cloud.dubbo.registry.SpringCloudRegistryFactory.ADDRESS;import static com.alibaba.cloud.dubbo.registry.SpringCloudRegistryFactory.PROTOCOL;import static org.springframework.util.ObjectUtils.isEmpty;
/** * Dubbo Service Registration Auto-{@link Configuration}. * * @author Mercy */@Configuration(proxyBeanMethods = false)@Import({DubboServiceRegistrationEventPublishingAspect.class})@ConditionalOnProperty(value = "spring.cloud.service-registry.auto-registration.enabled", matchIfMissing = true)@AutoConfigureAfter(name = {EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME, CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME, "org.springframework.cloud.client.serviceregistry.AutoServiceRegistrationAutoConfiguration"}, value = {DubboMetadataAutoConfiguration.class})public class DubboServiceRegistrationAutoConfiguration {
    /**     * EurekaClientAutoConfiguration.     */    public static final String EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME = "org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration";
    /**     * ConsulAutoServiceRegistrationAutoConfiguration.     */    public static final String CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME = "org.springframework.cloud.consul.serviceregistry.ConsulAutoServiceRegistrationAutoConfiguration";
    /**     * ConsulAutoRegistration.     */    public static final String CONSUL_AUTO_SERVICE_AUTO_REGISTRATION_CLASS_NAME = "org.springframework.cloud.consul.serviceregistry.ConsulAutoRegistration";
    /**     * ZookeeperAutoServiceRegistrationAutoConfiguration.     */    public static final String ZOOKEEPER_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME = "org.springframework.cloud.zookeeper.serviceregistry.ZookeeperAutoServiceRegistrationAutoConfiguration";
    private static final Logger logger = LoggerFactory.getLogger(DubboServiceRegistrationAutoConfiguration.class);
    @Autowired    private DubboServiceMetadataRepository dubboServiceMetadataRepository;
    @Bean    @Conditional({MissingSpringCloudRegistryConfigPropertyCondition.class})    public RegistryConfig defaultSpringCloudRegistryConfig() {        return new RegistryConfig(ADDRESS, PROTOCOL);    }
    private Map<ServiceRegistry<Registration>, Set<Registration>> registrations = new ConcurrentHashMap<>();
    @Order    @EventListener(ApplicationContextEvent.class)    public void attachDubboMetadataAndRegistAgain(ApplicationContextEvent event) {        registrations.forEach((registry, registrations) -> registrations.forEach(registration -> {            attachDubboMetadataServiceMetadata(registration);            registry.register(registration);        }));    }
    @EventListener(ServiceInstancePreRegisteredEvent.class)    public void onServiceInstancePreRegistered(ServiceInstancePreRegisteredEvent event) {        Registration registration = event.getSource();        ServiceRegistry<Registration> registry = event.getRegistry();        synchronized (registry) {            registrations.putIfAbsent(registry, new HashSet<>());            registrations.get(registry).add(registration);        }    }
    @EventListener(ServiceInstancePreDeregisteredEvent.class)    public void onServiceInstancePreDeregistered(ServiceInstancePreDeregisteredEvent event) {        ServiceRegistry<Registration> registry = event.getRegistry();        registrations.remove(registry);    }
    private void attachDubboMetadataServiceMetadata(Registration registration) {        if (registration == null) {            return;        }        synchronized (registration) {            Map<String, String> metadata = registration.getMetadata();            attachDubboMetadataServiceMetadata(metadata);        }    }
    private void attachDubboMetadataServiceMetadata(Map<String, String> metadata) {        Map<String, String> serviceMetadata = dubboServiceMetadataRepository.getDubboMetadataServiceMetadata();        if (!isEmpty(serviceMetadata)) {            metadata.putAll(serviceMetadata);        }    }
    /*@Configuration(proxyBeanMethods = false)    @ConditionalOnBean(name = EUREKA_CLIENT_AUTO_CONFIGURATION_CLASS_NAME)    class EurekaConfiguration implements SmartInitializingSingleton {
        @Autowired        private ObjectProvider> serviceBeans;
        @Order(Ordered.LOWEST_PRECEDENCE - 1)        @EventListener(ApplicationContextEvent.class)        public void onServiceInstancePreRegistered(ApplicationContextEvent event) {            registrations.forEach((registry, registrations) -> registrations.forEach(registration -> {                EurekaRegistration eurekaRegistration = (EurekaRegistration) registration;                InstanceInfo instanceInfo = eurekaRegistration.getApplicationInfoManager().getInfo();                attachDubboMetadataServiceMetadata(instanceInfo.getMetadata());            }));        }
        *//**     * {@link EurekaServiceRegistry} will register current {@link ServiceInstance     * service instance} on {@link EurekaAutoServiceRegistration#start()} execution(in     * {@link SmartLifecycle#start() start phase}), thus this method must     * {@link ServiceBean#export() export} all {@link ServiceBean ServiceBeans} in     * advance.     *//*        @Override        public void afterSingletonsInstantiated() {            Collection serviceBeans = this.serviceBeans.getIfAvailable();            if (!isEmpty(serviceBeans)) {                serviceBeans.forEach(ServiceBean::export);            }        }
    }*/
    /*@Configuration(proxyBeanMethods = false)    @ConditionalOnBean(name = CONSUL_AUTO_SERVICE_AUTO_CONFIGURATION_CLASS_NAME)    @AutoConfigureOrder    class ConsulConfiguration {
        @Order(Ordered.LOWEST_PRECEDENCE - 1)        @EventListener(ApplicationContextEvent.class)        public void attachURLsIntoMetadataBeforeReRegist(ApplicationContextEvent event) {            registrations.entrySet().removeIf(entry -> {                Set registrations = entry.getValue();                registrations.removeIf(registration -> {                    Class registrationClass = AopUtils.getTargetClass(registration);                    String registrationClassName = registrationClass.getName();                    return !CONSUL_AUTO_SERVICE_AUTO_REGISTRATION_CLASS_NAME                            .equalsIgnoreCase(registrationClassName);                });                return registrations.isEmpty();            });
            registrations.forEach(                    (registry, registrations) -> registrations.forEach(registration -> {                        ConsulRegistration consulRegistration = (ConsulRegistration) registration;                        attachURLsIntoMetadata(consulRegistration);                    }));        }
        private void attachURLsIntoMetadata(ConsulRegistration consulRegistration) {            NewService newService = consulRegistration.getService();            Map serviceMetadata = dubboServiceMetadataRepository                    .getDubboMetadataServiceMetadata();            if (!isEmpty(serviceMetadata)) {                List tags = newService.getTags();                for (Map.Entry entry : serviceMetadata.entrySet()) {                    tags.add(entry.getKey() + "=" + entry.getValue());                }            }        }
    }*/
}

之前那两篇文章大致的思路上大致方向是对的，Spring-Cloud-Start-dubbo-2.2.6-RELEASE和Spring-Cloud-Start-dubbo-2.2.7-RELEASE的springBoot的基本流程是一样的，nacos的注册是在在servlet容器启动后进行，dubbo的BootStrap.start()触发是在容器刷新后触发，由于2.3.x的springBoot的版本的容器刷新事件是在nacos的servlet容器启动之后（之前的思路是将dubbo.start()触发提前到nacos注册服务之前，这种是行不通的，因为Spring-Cloud-Start-dubbo的服务注册的start的流程上就有问题，提前这个顺序只会搞出更多的问题），所以就有有dubbo服务还没有注册完，所以就没有触发更新和通知操作

spring-context-5.2.15.RELEASE

@Override  public void refresh() throws BeansException, IllegalStateException {    synchronized (this.startupShutdownMonitor) {      // Prepare this context for refreshing.      prepareRefresh();
      // Tell the subclass to refresh the internal bean factory.      ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
      // Prepare the bean factory for use in this context.      prepareBeanFactory(beanFactory);
      try {        // Allows post-processing of the bean factory in context subclasses.        postProcessBeanFactory(beanFactory);
        // Invoke factory processors registered as beans in the context.        invokeBeanFactoryPostProcessors(beanFactory);
        // Register bean processors that intercept bean creation.        registerBeanPostProcessors(beanFactory);
        // Initialize message source for this context.        initMessageSource();
        // Initialize event multicaster for this context.        initApplicationEventMulticaster();
        // Initialize other special beans in specific context subclasses.                //这里是servelet容器启动后会触发通知nacos注册        onRefresh();
        // Check for listener beans and register them.        registerListeners();
        // Instantiate all remaining (non-lazy-init) singletons.        finishBeanFactoryInitialization(beanFactory);
        // Last step: publish corresponding event.                //这里是触发dubbo启动；        finishRefresh();      }
      catch (BeansException ex) {        if (logger.isWarnEnabled()) {          logger.warn("Exception encountered during context initialization - " +              "cancelling refresh attempt: " + ex);        }
        // Destroy already created singletons to avoid dangling resources.        destroyBeans();
        // Reset 'active' flag.        cancelRefresh(ex);
        // Propagate exception to caller.        throw ex;      }
      finally {        // Reset common introspection caches in Spring's core, since we        // might not ever need metadata for singleton beans anymore...        resetCommonCaches();      }    }  }

finishRefresh();

protected void finishRefresh() {    // Clear context-level resource caches (such as ASM metadata from scanning).    clearResourceCaches();
    // Initialize lifecycle processor for this context.    initLifecycleProcessor();
    // Propagate refresh to lifecycle processor first.    getLifecycleProcessor().onRefresh();        // 容器刷新时间，触发dubbStrap.start();    // Publish the final event.    publishEvent(new ContextRefreshedEvent(this));
    // Participate in LiveBeansView MBean, if active.    LiveBeansView.registerApplicationContext(this);  }

start中的服务元数据注册管理：

private void attachDubboMetadataServiceMetadata(Map<String, String> metadata) {        Map<String, String> serviceMetadata = dubboServiceMetadataRepository.getDubboMetadataServiceMetadata();        if (!isEmpty(serviceMetadata)) {            metadata.putAll(serviceMetadata);        }    }

getDubboMetadataServiceMetadata方法

public Map<String, String> getDubboMetadataServiceMetadata() {
    List dubboMetadataServiceURLs = dubboMetadataServiceExporter.export();
    // remove the exported URLs of DubboMetadataService    removeDubboMetadataServiceURLs(dubboMetadataServiceURLs);
    Map<String, String> metadata = newHashMap();
    addDubboMetadataServiceURLsMetadata(metadata, dubboMetadataServiceURLs);    addDubboProtocolsPortMetadata(metadata);    addRevision(metadata);
    return Collections.unmodifiableMap(metadata);  }

addDubboProtocolsPortMetadata方法

private void addDubboProtocolsPortMetadata(Map<String, String> metadata) {
    allExportedURLs.values().stream().flatMap(v -> v.stream()).forEach(url -> {      String protocol = url.getProtocol();      String propertyName = getDubboProtocolPropertyName(protocol);      String propertyValue = valueOf(url.getPort());      metadata.put(propertyName, propertyValue);    });  }

通过去源码里面找allExportedURLs的逻辑，大致猜测可以知道，当服务注册、变更(刷新)或失败等会有一些触发服务变更通知订阅者的逻辑，这样在只要是服务有变动都可以感知到，然后nacos通知到订阅者，你订阅的服务有变动了，你需要拉取下最新的服务然后更新下本地的服务列表，这个就是我大致的逻辑猜测。

private final MultiValueMap<String, URL> allExportedURLs = new LinkedMultiValueMap<>();

4.验证

在公司测试环境依赖使用的是之前升级后的依赖，然后使用上面那个start部署测试环境后，服务提供者部署重启，服务消费者不用重启，然后访问应用，服务消费者可以正常的访问到服务提供者的服务。

5.总结

希望我的分享对你有帮助，有兴趣的可以去看下dubbo的相关源码和具体的逻辑是怎样的，上面的是我的一些猜测(合理的猜想 + 验证)，感觉是这么一个感觉，请一键三连，么么么哒！

spring-cloud-alibaba-dubbo-issues1805修复

1.官方信息

2.版本代码对比

3.修改尝试

4.验证

5.总结