<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>2.1.6.RELEASE</version>
<relativePath>../../spring-boot-dependencies</relativePath>
</parent>
springboot 的版本管理器
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-*</artifactId>
</dependency>
springboot的启动器，可以帮助导入相关的依赖
@SpringBootApplication //springboot的主程序注解
//该注解又由以下注解构成
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
@Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
public @interface SpringBootApplication {
@SpringBootConfiguration //这是一个springboot的配置类
@configuration //配置类也是容器中的一个组件
@EnableAutoConfiguration //开启自动配置
//该注解内有以下注解 @AutoConfigurationPackage //将主配置类下的所有的包都扫描到容器中
@Import(AutoConfigurationImportSelector.class)
@AutoConfigurationPackage //自动配置包
@Import(AutoConfigurationPackages.Registrar.class)
spring中底层的注解@Import，给容器中导入一个组件