一、簡介

　　搭建springcloud-nacos發現不加@EnableDiscoveryClient也可以把服務注冊到注冊中心，帶這疑惑看了源碼總結下。

　　服務注冊時牽扯到的幾個主要類：NacosDiscoveryAutoConfiguration、NacosAutoServiceRegistration、AbstractAutoServiceRegistration、Registration等

二、源碼初探

　　（１）首先看幾個類是如何注冊到spring容器

　　　　NacosDiscoveryAutoConfiguration感覺就是配置類，NacosAutoServiceRegistration也會被加載（＠Configuration\@Bean被ConfigurationClassPostProcessor解析，原理后續文章講解，還沒細看）　　　

@Configuration
@EnableConfigurationProperties
@ConditionalOnNacosDiscoveryEnabled
@ConditionalOnProperty(value = "spring.cloud.service-registry.auto-registration.enabled", matchIfMissing = true)
@AutoConfigureAfter({ AutoServiceRegistrationConfiguration.class,
        AutoServiceRegistrationAutoConfiguration.class })
public class NacosDiscoveryAutoConfiguration {

    @Bean
    public NacosServiceRegistry nacosServiceRegistry(
            NacosDiscoveryProperties nacosDiscoveryProperties) {
        return new NacosServiceRegistry(nacosDiscoveryProperties);
    }

    @Bean
    @ConditionalOnBean(AutoServiceRegistrationProperties.class)
    public NacosRegistration nacosRegistration(
            NacosDiscoveryProperties nacosDiscoveryProperties,
            ApplicationContext context) {
        return new NacosRegistration(nacosDiscoveryProperties, context);
    }

    @Bean
    @ConditionalOnBean(AutoServiceRegistrationProperties.class)
    public NacosAutoServiceRegistration nacosAutoServiceRegistration(
            NacosServiceRegistry registry,
            AutoServiceRegistrationProperties autoServiceRegistrationProperties,
            NacosRegistration registration) {
        return new NacosAutoServiceRegistration(registry,
                autoServiceRegistrationProperties, registration);
    }
}