【springboot】@SpringBootApplication 加载原理解析

从何处放入

AutoConfigurationImportSelector.selectImports

AbstractApplicationContext.refresh
AbstractApplicationContext.invokeBeanFactoryPostProcessors
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors
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此处一个关键信息只有BeanDefinitionRegistryPostProcessor的，才会有下面的逻辑，下面是这个类的注释

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ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry
ConfigurationClassPostProcessor.processConfigBeanDefinitions
ConfigurationClassParser.parse
ConfigurationClassParser.process
ConfigurationClassParser.processGroupImports
ConfigurationClassParser.getImports
AutoConfigurationImportSelector.process
AutoConfigurationImportSelector.getAutoConfigurationEntry
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从此方法获取到了默认需要加载的类，返回 AutoConfigurationEntry

AbstractApplicationContext.refresh
AbstractApplicationContext.invokeBeanFactoryPostProcessors
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors
ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry
ConfigurationClassPostProcessor.processConfigBeanDefinitions

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ConfigurationClassBeanDefinitionReader.loadBeanDefinitions
ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass

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ConfigurationClassBeanDefinitionReader.registerBeanDefinitionForImportedConfigurationClass
DefaultListableBeanFactory.registerBeanDefinition

至此，完成了第一步,放入了DefaultListableBeanFactory 的 beanDefinitionMap及beanDefinitionNames中

从何处取出并创建bean

AbstractApplicationContext.refresh
AbstractApplicationContext.finishBeanFactoryInitialization
DefaultListableBeanFactory.preInstantiateSingletons

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接下来就是创建bean的流程了

AbstractBeanFactory.getBean
DefaultSingletonBeanRegistry.getSingleton
AbstractBeanFactory.getObject
AbstractAutowireCapableBeanFactory.createBean
AbstractAutowireCapableBeanFactory.doCreateBean
AbstractAutowireCapableBeanFactory.createBeanInstance
AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod
ConstructorResolver.instantiateUsingFactoryMethod
ConstructorResolver.instantiate
SimpleInstantiationStrategy.instantiate

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