@SpringBootApplication注解

一、@SpringBootApplication是一个组合注解,加在项目启动类上。

二、@SpringBootApplication定义:

@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
		@Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
public @interface SpringBootApplication {
 //略
}

可以看出@SpringBootApplication由三个注解组成。

  • @SpringBootConfiguration ,本质是一个@Configuration配置类(类似一个SpringContext.xml文件),可以通过@Bean定义方法定义Bean。
/**
 * Indicates that a class provides Spring Boot application
 * {@link Configuration @Configuration}. Can be used as an alternative to the Spring's
 * standard {@code @Configuration} annotation so that configuration can be found
 * automatically (for example in tests).
 * 

* Application should only ever include one {@code @SpringBootConfiguration} and * most idiomatic Spring Boot applications will inherit it from * {@code @SpringBootApplication}. * * @author Phillip Webb * @author Andy Wilkinson * @since 1.4.0 */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Configuration public @interface SpringBootConfiguration { //*** }

  •   @EnableAutoConfiguration 自动配置类  
@AutoConfigurationPackage
@Import(AutoConfigurationImportSelector.class)
public @interface EnableAutoConfiguration {

	String ENABLED_OVERRIDE_PROPERTY = "spring.boot.enableautoconfiguration";

	/**
	 * Exclude specific auto-configuration classes such that they will never be applied.
	 * @return the classes to exclude
	 */
	Class[] exclude() default {};

	/**
	 * Exclude specific auto-configuration class names such that they will never be
	 * applied.
	 * @return the class names to exclude
	 * @since 1.3.0
	 */
	String[] excludeName() default {};

}
  • @ComponentScan 组件扫描类. 类似SpringContext.xml文件zhong的
@Repeatable(ComponentScans.class)
public @interface ComponentScan {
//
}

 

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