SpringBoot重要的几个注解
SpringBootApplication外面包含 EnableAutoConfiguration、SpringBootConfiguration、ComponentScan
EnableAutoConfiguration：启动主动拆卸
AutoConfigurationPackage
@Import(AutoConfigurationImportSelector.class) 主动拆卸导入类
ComponentScan：包扫描,默认是启动类以后包
SpringBoot启动 --SpringApplication.run(<以后启动类>,arg)--以后主动类(primarySource)--prepareContext()容器事后初始化工作--load 加载以后启动类
--refreshContext(相熟的refresh办法,Spring容器创立以及初始化相干操作)-- invokeBeanFactoryPostProcessors(beanFactory);
执行BeanFactoryPostProcessors办法
执行
invokeBeanFactoryPostProcessors中重要一步 BeanDefinitionRegistryPostProcessor bean定义信息处理器 实现类
ConfigurationClassPostProcessor（重要）实现了 postProcessBeanDefinitionRegistry
processConfigBeanDefinitions 配置Bean的定义信息
doProcessConfigurationClass 解析Configuration注解
processImports(configClass, sourceClass, getImports(sourceClass), true);// 递归的解析配置类的注解 蕴含importprivate void collectImports(SourceClass sourceClass, Set<SourceClass> imports, Set<SourceClass> visited) throws IOException { if (visited.add(sourceClass)) { for (SourceClass annotation : sourceClass.getAnnotations()) { String annName = annotation.getMetadata().getClassName(); if (!annName.equals(Import.class.getName())) { collectImports(annotation, imports, visited); } } imports.addAll(sourceClass.getAnnotationAttributes(Import.class.getName(), "value")); } } ///执行this.deferredImportSelectorHandler.process(); public void process() { List<DeferredImportSelectorHolder> deferredImports = this.deferredImportSelectors; this.deferredImportSelectors = null; try { if (deferredImports != null) { DeferredImportSelectorGroupingHandler handler = new DeferredImportSelectorGroupingHandler(); deferredImports.sort(DEFERRED_IMPORT_COMPARATOR); deferredImports.forEach(handler::register); //开始执行Import注解 handler.processGroupImports(); } } finally { this.deferredImportSelectors = new ArrayList<>(); } } }//执行办法 public void processGroupImports() { for (DeferredImportSelectorGrouping grouping : this.groupings.values()) { //这步 grouping.getImports().forEach(entry -> { ConfigurationClass configurationClass = this.configurationClasses.get( entry.getMetadata()); try { processImports(configurationClass, asSourceClass(configurationClass), asSourceClasses(entry.getImportClassName()), false); } catch (BeanDefinitionStoreException ex) { throw ex; } catch (Throwable ex) { throw new BeanDefinitionStoreException( "Failed to process import candidates for configuration class [" + configurationClass.getMetadata().getClassName() + "]", ex); } }); } }//下一步public Iterable<Group.Entry> getImports() { for (DeferredImportSelectorHolder deferredImport : this.deferredImports) {//实现类 AutoConfigurationImportSelector this.group.process(deferredImport.getConfigurationClass().getMetadata(), deferredImport.getImportSelector()); } return this.group.selectImports(); } //AutoConfigurationImportSelector 实现类@Override public void process(AnnotationMetadata annotationMetadata, DeferredImportSelector deferredImportSelector) { Assert.state(deferredImportSelector instanceof AutoConfigurationImportSelector, () -> String.format("Only %s implementations are supported, got %s", AutoConfigurationImportSelector.class.getSimpleName(), deferredImportSelector.getClass().getName())); AutoConfigurationEntry autoConfigurationEntry = ((AutoConfigurationImportSelector) deferredImportSelector)//获取 AutoConfigurationEntry .getAutoConfigurationEntry(getAutoConfigurationMetadata(), annotationMetadata); this.autoConfigurationEntries.add(autoConfigurationEntry); for (String importClassName : autoConfigurationEntry.getConfigurations()) { this.entries.putIfAbsent(importClassName, annotationMetadata); } }//下一步 这步就开始清晰了 protected AutoConfigurationEntry getAutoConfigurationEntry(AutoConfigurationMetadata autoConfigurationMetadata, AnnotationMetadata annotationMetadata) { if (!isEnabled(annotationMetadata)) { return EMPTY_ENTRY; } AnnotationAttributes attributes = getAttributes(annotationMetadata); //主动拆卸开始 List<String> configurations = getCandidateConfigurations(annotationMetadata, attributes); configurations = removeDuplicates(configurations); Set<String> exclusions = getExclusions(annotationMetadata, attributes); checkExcludedClasses(configurations, exclusions); configurations.removeAll(exclusions); configurations = filter(configurations, autoConfigurationMetadata); fireAutoConfigurationImportEvents(configurations, exclusions); return new AutoConfigurationEntry(configurations, exclusions); } // getCandidateConfigurations办法protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) { List<String> configurations = //getSpringFactoriesLoaderFactoryClass 就是获取 EnableAutoConfiguration.class这个主动拆卸类//SpringFactoriesLoader 加载默认目录 META-INF/spring.factories 上面 加载主动拆卸EnableAutoConfiguration 这种类型的bean 此时加载的只是作为bean的定义信息 SpringFactoriesLoader.loadFactoryNames(getSpringFactoriesLoaderFactoryClass(), getBeanClassLoader()); Assert.notEmpty(configurations, "No auto configuration classes found in META-INF/spring.factories. If you " + "are using a custom packaging, make sure that file is correct."); return configurations; }加载bean的定义信息到beanfactory 接下来就是 Beanfactory 执行bean的生命周期流程 总结：SpringBoot启动 SpringApplication.run办法传入以后启动类primarySources
加载以后配置类 在refreshContext中invokeBeanFactoryPostProcessors 执行BeanFactoryPostProcessors(ConfigurationClassPostProcessor) 加载那些主动配置的bean的定义信息、加载实现 执行后续的beanfactory创立bean的流程