【SpringBoot】@SpringBootApplication

注解定义

@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 {
    @AliasFor(annotation = EnableAutoConfiguration.class) Class<?>[] exclude() default {};

    @AliasFor(annotation = EnableAutoConfiguration.class) String[] excludeName() default {};

    @AliasFor(annotation = ComponentScan.class, attribute = "basePackages") String[] scanBasePackages() default {};

    @AliasFor(annotation = ComponentScan.class,
        attribute = "basePackageClasses") Class<?>[] scanBasePackageClasses() default {};

    @AliasFor(annotation = ComponentScan.class,
        attribute = "nameGenerator") Class<? extends BeanNameGenerator> nameGenerator() default BeanNameGenerator.class;

    @AliasFor(annotation = Configuration.class) boolean proxyBeanMethods() default true;
}

@SpringBootConfiguration

　- @Configuration

@EnableAutoConfiguration

　　- @AutoConfigurationPackage

　　　　-- @Import({Registrar.class})

static class Registrar implements ImportBeanDefinitionRegistrar, DeterminableImports {
        Registrar() {
        }

        public void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefinitionRegistry registry) {
            AutoConfigurationPackages.register(registry, (String[])(new AutoConfigurationPackages.PackageImports(metadata)).getPackageNames().toArray(new String[0]));
        }

        public Set<Object> determineImports(AnnotationMetadata metadata) {
            return Collections.singleton(new AutoConfigurationPackages.PackageImports(metadata));
        }
    }

　　- @Import({AutoConfigurationImportSelector.class})

　　- {String ENABLED_OVERRIDE_PROPERTY = "spring.boot.enableautoconfiguration";}

public class AutoConfigurationImportSelector implements DeferredImportSelector, BeanClassLoaderAware, ResourceLoaderAware, BeanFactoryAware, EnvironmentAware, Ordered {
    private static final AutoConfigurationImportSelector.AutoConfigurationEntry EMPTY_ENTRY = new AutoConfigurationImportSelector.AutoConfigurationEntry();
    private static final String[] NO_IMPORTS = new String[0];
    private static final Log logger = LogFactory.getLog(AutoConfigurationImportSelector.class);
    private static final String PROPERTY_NAME_AUTOCONFIGURE_EXCLUDE = "spring.autoconfigure.exclude";
    private ConfigurableListableBeanFactory beanFactory;
    private Environment environment;
    private ClassLoader beanClassLoader;
    private ResourceLoader resourceLoader;
    private AutoConfigurationImportSelector.ConfigurationClassFilter configurationClassFilter;

@ComponentScan