@EnableDiscoveryClient和@EnableEurekaClient注解都是向服务注册中心进行注册。
@EnableDiscoveryClient基于spring-cloud-commons，@EnableEurekaClient基于spring-cloud-netflix。
另外，@EnableEurekaClient具有@EnableDiscoveryClient的功能，而且更加针对于注册中心为Eureka的服务。以下是@EnableEurekaClient注解的源码
/**
* Convenience annotation for clients to enable Eureka discovery configuration
* (specifically). Use this (optionally) in case you want discovery and know for sure that
* it is Eureka you want. All it does is turn on discovery and let the autoconfiguration
* find the eureka classes if they are available (i.e. you need Eureka on the classpath as
* well).
*
* @author Dave Syer
* @author Spencer Gibb
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@EnableDiscoveryClient
public @interface EnableEurekaClient {
}