Spring原始碼之事務(一）— TransactionAutoConfiguration自動配置
阿新 • • 發佈：2020-11-19
#### 總結：
- 在ConfigurationClassParser#parse（）中會對deferredImportSelectorHandler進行處理（在處理@ComponentScan 自己所寫@Component的類後）
- 處理過程中會呼叫SpringFactoriesLoader#loadFactoryNames(),去查詢所有jar下面META-INF/spring.factories中key為org.springframework.boot.autoconfigure.EnableAutoConfiguration的值
- ConfigurationClassPostProcessor#processConfigBeanDefinitions()中loadBeanDefinitions對TransactionAutoConfiguration進行BeanDefinition的載入，並註冊IOC容器
#### TransactionAutoConfiguration的BeanDefinition載入解析
呼叫鏈：
> AbstractApplicationContext#refresh() --> AbstractApplicationContext#invokeBeanFactoryPostProcessors() --> PostProcessorRegistrationDelegate#invokeBeanFactoryPostProcessors() --> PostProcessorRegistrationDelegate#invokeBeanDefinitionRegistryPostProcessors() --> ConfigurationClassPostProcessor#postProcessBeanDefinitionRegistry（）--> ConfigurationClassPostProcessor#processConfigBeanDefinitions() --> ConfigurationClassPostProcessor#parse() --> ConfigurationClassParser#process() --> ConfigurationClassParser$DeferredImportSelectorGroupingHandler#processGroupImports() --> ConfigurationClassParser#processImports() --> ConfigurationClassParser#processConfigurationClass() --> ConfigurationClassParser#doProcessConfigurationClass()
ConfigurationClassParser#parse() 對延遲ImportSelector進行處理
```
private final DeferredImportSelectorHandler deferredImportSelectorHandler = new DeferredImportSelectorHandler();
public void p