以下选自官方的文档

Many Spring Boot developers always have their main class annotated with @Configuration, @EnableAutoConfiguration, @ComponentScan. Since these annotations are so frequently used together (especially if you follow the best practices above), Spring Boot provides a convenient @SpringBootApplication alternative. 翻译：许多SpringBoot的开发者都喜欢在主方法中注解。 因为这些注解是很频繁的在一起使用，SpringBoot提供了一个更加便捷的注解@SpringBootApplication，来替代三个一起使用。 意思就是：一个抵三个。 @Configuration：配置 @EnableAutoConfiguration：自动加载配置 @ComponentScan：扫描指定的包

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The @SpringBootApplication annotation is equivalent to using @Configuration, @EnableAutoConfiguration, and @ComponentScan with their default attributes, as shown in the following example:

package com.example.myapplication;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication // same as @Configuration @EnableAutoConfiguration @ComponentScanpublic class Application {
         public static void main(String[] args) {        SpringApplication.run(Application.class, args);    }}

ps：@SpringBootApplication also provides aliases to customize the attributes of @EnableAutoConfiguration and @ComponentScan.