SpringCloud 基于Nacos和Eureka 实现双注册双订阅_Java

一、使用场景/原因

过渡期迁移:
- 当系统从一个服务注册中心迁移到另一个时，例如从 eureka 迁移到 nacos，可以在过渡期内同时使用两个注册中心，确保服务平稳迁移，逐步过渡，避免一次性切换带来的风险。
兼容性考虑:
- 不同的微服务可能使用不同的注册中心，为了兼容这些微服务，可以同时支持 nacos 和 eureka。这样既可以支持新开发的服务使用 nacos，也可以兼容旧有的使用 eureka 的服务。

二、增加注册中心

2.1、pom文件分别配置nacos、eureka

<dependency>
    <groupid>com.alibaba.cloud</groupid>
    <artifactid>spring-cloud-starter-alibaba-nacos-discovery</artifactid>
</dependency>
<dependency>
    <groupid>org.springframework.cloud</groupid>
    <artifactid>spring-cloud-starter-netflix-eureka-client</artifactid>
</dependency>

2.2、启动类注解

@springbootapplication
//@enableeurekaclient
@enablediscoveryclient
public class application {
    public static void main(string[] args) {
        springapplication.run(application.class, args);
    }

}

2.3、项目配置文件application.yml

eureka:
  client:
    serviceurl:
      defaultzone: http://localhost:9002/eureka/
  instance:
    prefer-ip-address: true
server:
  port: 11500
spring:
  application:
    name: ko
  cloud:
    service-registry:
      auto-registration:
        enabled: false
    nacos:
      discovery:
        server-addr: http://127.0.0.1:9999
        namespace: 47dea8bf-3dce-4c86-82bc-82f1497c57d2

三、启动项目

3.1、自动注册时候报错

图和文字是一样的为了方便看，可方便复制

disconnected from the target vm, address: 'localhost:63051', transport: 'socket'
***************************
application failed to start
***************************

description:

field autoserviceregistration in org.springframework.cloud.client.serviceregistry.autoserviceregistrationautoconfiguration required a single bean, but 2 were found:
	- nacosautoserviceregistration: defined by method 'nacosautoserviceregistration' in class path resource [com/alibaba/cloud/nacos/registry/nacosserviceregistryautoconfiguration.class]
	- eurekaautoserviceregistration: defined by method 'eurekaautoserviceregistration' in class path resource [org/springframework/cloud/netflix/eureka/eurekaclientautoconfiguration.class]


action:

consider marking one of the beans as @primary, updating the consumer to accept multiple beans, or using @qualifier to identify the bean that should be consumed

3.2、注入失败问题解决

3.2.1 application.yml 配置方式 autoconfigure.exclude

spring:
  application:
    name: ko
  cloud:
    nacos:
      discovery:
        server-addr: http://127.0.0.1:9999
        namespace: 47dea8bf-3dce-4c86-82bc-82f1497c57d2
      config:
        enabled: false
        server-addr: http://127.0.0.1:9999
        import-check: false
        namespace: 47dea8bf-3dce-4c86-82bc-82f1497c57d2
  autoconfigure:
    exclude: org.springframework.cloud.client.serviceregistry.autoserviceregistrationautoconfiguration

3.2.2 application 启动类配置方式

// exclude 同样可以起到忽略的作用 ,至于这里为什么要忽略两个，继续往下看，会说到
@springbootapplication(exclude = {autoserviceregistrationautoconfiguration.class，serviceregistryautoconfiguration.class})
@enablediscoveryclient
public class application {
    public static void main(string[] args) {
        springapplication.run(application.class, args);
    }

}

***************************
application failed to start
***************************

description:

field registration in org.springframework.cloud.client.serviceregistry.serviceregistryautoconfiguration$serviceregistryendpointconfiguration required a single bean, but 2 were found:
	- nacosregistration: defined by method 'nacosregistration' in class path resource [com/alibaba/cloud/nacos/registry/nacosserviceregistryautoconfiguration.class]
	- eurekaregistration: defined in beandefinition defined in class path resource [org/springframework/cloud/netflix/eureka/eurekaclientautoconfiguration$refreshableeurekaclientconfiguration.class]


action:

consider marking one of the beans as @primary, updating the consumer to accept multiple beans, or using @qualifier to identify the bean that should be consumed
 ******** 
disconnected from the target vm, address: 'localhost:63833', transport: 'socket'

/**
 * @author spencer gibb
 */
@configuration(proxybeanmethods = false)
public class serviceregistryautoconfiguration {

	@conditionalonbean(serviceregistry.class)
	@conditionalonclass(endpoint.class)
	protected class serviceregistryendpointconfiguration {

		@autowired(required = false)
		private registration registration;

		@bean
		@conditionalonenabledendpoint
		public serviceregistryendpoint serviceregistryendpoint(
				serviceregistry serviceregistry) {
			serviceregistryendpoint endpoint = new serviceregistryendpoint(
					serviceregistry);
			endpoint.setregistration(this.registration);
			return endpoint;
		}

	}

}