一、问题现象

Description:

Field autoServiceRegistration in org.springframework.cloud.client.serviceregistry.AutoServiceRegistrationAutoConfiguration required a single bean, but 2 were found:
	- eurekaAutoServiceRegistration: defined by method 'eurekaAutoServiceRegistration' in class path resource [org/springframework/cloud/netflix/eureka/EurekaClientAutoConfiguration.class]
	- nacosAutoServiceRegistration: defined by method 'nacosAutoServiceRegistration' in class path resource [com/alibaba/cloud/nacos/registry/NacosServiceRegistryAutoConfiguration.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

二、解决办法

检查pom文件中，是不是同时添加了Nacos和Eureka的依赖？如果是，选择一个不必要的去掉即可。比如这次异常，我保留了Nacos，去掉了Eureka。

<!--Eureka客户端-->
<!--<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    <version>2.2.6.RELEASE</version>
</dependency>-->

<!--nacos客户端-->
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
    <version>2.2.6.RELEASE</version>
</dependency>

三、原因分析

Spring Boot项目启动时，AutoServiceRegistrationAutoConfiguration类需要注入一个类型为AutoServiceRegistration的bean。但是，在容器中却出现了两个Bean，其父类均为AutoServiceRegistration，就是异常中打印出的nacosAutoServiceRegistration和eurekaAutoServiceRegistration。

异常中还顺便给出了解决方案：即为其中一个bean添加注解@Primary或@Qualifier。其实，简单的解决办法就是去掉无用的依赖即可。如果其他大佬有不同看法，可以留言讨论。