SpringBoot 自动配置原理

loadMetadata() 方法将所有jar 包中的 META-INF/spring-autoconfigure-metadata.properties文件加载并解析，也就将自动配置类的元数据加载进内存了

AutoConfigurationGroup

处理从配置文件中解析出来的自动配置类

processImports()

1.1.1.1.2 processImports()

1.1 parse()

DeferredImportSelectorGroupingHandler

1.2.2.1.1.2 deferredImportSelector.getAutoConfigurationEntry()

loadMetadata()

1.2 this.deferredImportSelectorHandler.process()

SpringFactoriesLoader.loadFactoryNames()

获取 @Import 配置的类

getCandidateConfigurations()

DeferredImportSelectorHandler

loadSpringFactories() 将所有 jar 包中的 META-INF/spring.factories 文件加载并解析，也就将文件中的自动配置类名加载进内存

@Import(AutoConfigurationImportSelector.class)

1.2.2.1.1.1 getAutoConfigurationMetadata()

1.1.1.1.1 getImports()

1.1.1.1 doProcessConfigurationClass()

ConfigurationClassParser

1.1.1.1.2.1 this.deferredImportSelectorHandler.handle()

1.2.1 handler::register

processConfigurationClass()

1.2.2.1.1 this.group.process()

loadSpringFactories()

DeferredImportSelectorGrouping

AutoConfigurationImportSelector

AutoConfigurationMetadataLoader

@EnableAutoConfiguration

AutoConfigurationMetadataLoader.loadMetadata()

SpringFactoriesLoader

1.2.2 handler.processGroupImports()

1. parse()

1.2.2.1 grouping.getImports()

1.1.1 processConfigurationClass()