springboot-spring-ioc-annotation源码学习

太过爱你忘了你带给我的痛 2024-02-19 16:52 32阅读 0赞

> 如果看完之后感觉内容较多可以参考总结版：https://blog.csdn.net/u010597819/article/details/87456084

#### springboot启动 ####

1.  SpringApplication.run(Application.class, args)

public static ConfigurableApplicationContext run(Object[] sources, String[] args) {
    	return new SpringApplication(sources).run(args);
    }

1.  创建SpringApplication
2.  SpringApplication初始化initialize
3.  Application.class放入sources中
4.  判断是否web环境，commonClassCache，classloader中是否可以存在这些class

private static final String[] WEB_ENVIRONMENT_CLASSES = { "javax.servlet.Servlet",
    	"org.springframework.web.context.ConfigurableWebApplicationContext" };

1.  设置初始化对象（ApplicationContextInitializer 的实现）setInitializers，从工厂实例中获取实现getSpringFactoriesInstances即META-INF/spring.factories中
2.  设置监听对象（ApplicationListener 的实现）setListeners，从工厂实例中获取实现getSpringFactoriesInstances即META-INF/spring.factories中
3.  获取被设置主类入口：mainApplicationClass，遍历当前堆栈信息获取

#### SpringApplication启动run(args) ####

/**
     * Run the Spring application, creating and refreshing a new
     * {@link ApplicationContext}.
     * @param args the application arguments (usually passed from a Java main method)
     * @return a running {@link ApplicationContext}
     */
    public ConfigurableApplicationContext run(String... args) {
    	StopWatch stopWatch = new StopWatch();
    	stopWatch.start();
    	ConfigurableApplicationContext context = null;
    	FailureAnalyzers analyzers = null;
    	configureHeadlessProperty();
    	SpringApplicationRunListeners listeners = getRunListeners(args);
    	listeners.starting();
    	try {
    		ApplicationArguments applicationArguments = new DefaultApplicationArguments(
    				args);
    		ConfigurableEnvironment environment = prepareEnvironment(listeners,
    				applicationArguments);
    		Banner printedBanner = printBanner(environment);
    		context = createApplicationContext();
    		analyzers = new FailureAnalyzers(context);
    		prepareContext(context, environment, listeners, applicationArguments,
    				printedBanner);
    		refreshContext(context);
    		afterRefresh(context, applicationArguments);
    		listeners.finished(context, null);
    		stopWatch.stop();
    		if (this.logStartupInfo) {
    			new StartupInfoLogger(this.mainApplicationClass)
    					.logStarted(getApplicationLog(), stopWatch);
    		}
    		return context;
    	}
    	catch (Throwable ex) {
    		handleRunFailure(context, listeners, analyzers, ex);
    		throw new IllegalStateException(ex);
    	}
    }

1.  获取运行监听对象（ApplicationListener 的实现）setListeners，从工厂实例中获取实现getSpringFactoriesInstances即META-INF/spring.factories中
2.  下面就是工厂实现类的配置

# PropertySource Loaders
    org.springframework.boot.env.PropertySourceLoader=\
    org.springframework.boot.env.PropertiesPropertySourceLoader,\
    org.springframework.boot.env.YamlPropertySourceLoader
    
    # Run Listeners
    org.springframework.boot.SpringApplicationRunListener=\
    org.springframework.boot.context.event.EventPublishingRunListener
    
    # Application Context Initializers
    org.springframework.context.ApplicationContextInitializer=\
    org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer,\
    org.springframework.boot.context.ContextIdApplicationContextInitializer,\
    org.springframework.boot.context.config.DelegatingApplicationContextInitializer,\
    org.springframework.boot.context.embedded.ServerPortInfoApplicationContextInitializer
    
    # Application Listeners
    org.springframework.context.ApplicationListener=\
    org.springframework.boot.ClearCachesApplicationListener,\
    org.springframework.boot.builder.ParentContextCloserApplicationListener,\
    org.springframework.boot.context.FileEncodingApplicationListener,\
    org.springframework.boot.context.config.AnsiOutputApplicationListener,\
    org.springframework.boot.context.config.ConfigFileApplicationListener,\
    org.springframework.boot.context.config.DelegatingApplicationListener,\
    org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener,\
    org.springframework.boot.logging.ClasspathLoggingApplicationListener,\
    org.springframework.boot.logging.LoggingApplicationListener
    
    # Environment Post Processors
    org.springframework.boot.env.EnvironmentPostProcessor=\
    org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\
    org.springframework.boot.env.SpringApplicationJsonEnvironmentPostProcessor
    
    # Failure Analyzers
    org.springframework.boot.diagnostics.FailureAnalyzer=\
    org.springframework.boot.diagnostics.analyzer.BeanCurrentlyInCreationFailureAnalyzer,\
    org.springframework.boot.diagnostics.analyzer.BeanNotOfRequiredTypeFailureAnalyzer,\
    org.springframework.boot.diagnostics.analyzer.BindFailureAnalyzer,\
    org.springframework.boot.diagnostics.analyzer.ConnectorStartFailureAnalyzer,\
    org.springframework.boot.diagnostics.analyzer.NoUniqueBeanDefinitionFailureAnalyzer,\
    org.springframework.boot.diagnostics.analyzer.PortInUseFailureAnalyzer,\
    org.springframework.boot.diagnostics.analyzer.ValidationExceptionFailureAnalyzer
    
    # FailureAnalysisReporters
    org.springframework.boot.diagnostics.FailureAnalysisReporter=\
    org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter

1.  启动监听listeners.starting();
2.  创建应用参数对象ApplicationArguments
3.  prepareEnvironment准备环境
4.  配置环境configureEnvironment
5.  运行监听器EventPublishingRunListener广播环境准备完成消息，使用taskExecutor线程池，根据事件类型获取ApplicationListener监听器集合回调onApplicationEvent
6.  打印环境信息printBanner
7.  createApplicationContext创建spring应用上下文，默认非web实现：AnnotationConfigApplicationContext，默认web环境实现AnnotationConfigEmbeddedWebApplicationContext

public AnnotationConfigApplicationContext() {
    	this.reader = new AnnotatedBeanDefinitionReader(this);
    	this.scanner = new ClassPathBeanDefinitionScanner(this);
    }

1.  创建AnnotatedBeanDefinitionReader

> 1.  registerAnnotationConfigProcessors注册处理对象
> 2.  获取上下文中的beanFactory即DefaultListableBeanFactory
> 3.  beanFactory工厂设置依赖比较器，默认为AnnotationAwareOrderComparator
> 4.  beanFactory工厂设置Autowired候选解析器，默认为ContextAnnotationAutowireCandidateResolver
> 5.  registerPostProcessor注册后置处理对象至BeanDefinitionRegistry internalConfigurationAnnotationProcessor：ConfigurationClassPostProcessor
> 6.  registerPostProcessor注册后置处理对象至BeanDefinitionRegistry internalAutowiredAnnotationProcessor：AutowiredAnnotationBeanPostProcessor
> 7.  registerPostProcessor注册后置处理对象至BeanDefinitionRegistry internalRequiredAnnotationProcessor：RequiredAnnotationBeanPostProcessor
> 8.  registerPostProcessor注册后置处理对象至BeanDefinitionRegistry internalCommonAnnotationProcessor：CommonAnnotationBeanPostProcessor
> 9.  registerPostProcessor注册后置处理对象至BeanDefinitionRegistry internalPersistenceAnnotationProcessor：PersistenceAnnotationBeanPostProcessor
> 10. registerPostProcessor注册后置处理对象至BeanDefinitionRegistry internalEventListenerProcessor：EventListenerMethodProcessor
> 11. registerPostProcessor注册后置处理对象至BeanDefinitionRegistry internalEventListenerFactory：DefaultEventListenerFactory

1.  ClassPathBeanDefinitionScanner创建

> 1.  registerDefaultFilters注册默认过滤器：AnnotationTypeFilter（Component、ManagedBean、Named）
> 2.  设置环境及ResourceLoader即应用上下文

1.  FailureAnalyzer失败分析接口绑定上下文中的beanFactory
2.  prepareContext准备上下文

> 1.  postProcessApplicationContext，启动时什么都不处理，因为resourceLoader，beanNameGenerator均为null
> 2.  applyInitializers应用初始化即ApplicationContextInitializer的工厂实现：ConfigurationWarningsApplicationContextInitializer、ContextIdApplicationContextInitializer、DelegatingApplicationContextInitializer、ServerPortInfoApplicationContextInitializer等初始化对象
> 3.  ConfigurationWarningsApplicationContextInitializer addBeanFactoryPostProcessor ，为应用上下文ApplicationContext添加ConfigurationWarningsPostProcessor后置处理
> 4.  ContextIdApplicationContextInitializer 为上下文设置id
> 5.  DelegatingApplicationContextInitializer 获取env环境中的context.initializer.classes配置的初始化类列表并初始化
> 6.  ServerPortInfoApplicationContextInitializer 上下文中添加EmbeddedServletContainerInitializedEvent事件类型的监听
> 7.  listeners.contextPrepared(context)广播上下文准备完成消息
> 8.  springApplicationArguments单例模式注册至工厂
> 9.  springBootBanner不为空的情况下同样单例模式注册至工厂
> 10. load加载上下文：createBeanDefinitionLoader创建bean定义加载器，如果isGroovyPresent则加载，如果source是component则加载，默认没有什么都不做
> 11. listeners.contextLoaded(context)监听广播上下文加载完成消息

1.  refreshContext刷新上下文

> 1.  调用AbstractApplicationContext刷新上下文：[spring XML 刷新上下文][spring XML]
> 2.  调用钩子方法registerShutdownHook

1.  AbstractApplicationContext刷新(注解版本刷新流程)
2.  \_\_prepareRefresh\_\_刷新前准备动作AnnotationConfigApplicationContext清空metadataReaderFactory缓存并调用父类准备动作
3.  \_\_obtainFreshBeanFactory\_\_获取工厂，refreshBeanFactory刷新工厂GenericApplicationContext父类更新刷新标识并设置上下文id其他什么都不处理，GenericApplicationContext.getBeanFactory返回工厂（GenericApplicationContext上下文无参构造器中对beanFactory完成创建）
4.  \_\_prepareBeanFactory\_\_准备beanFactory，设置StandardBeanExpressionResolver，添加ResourceEditorRegistrar、ApplicationContextAwareProcessor，添加忽略的依赖接口类型：EnvironmentAware、EmbeddedValueResolverAware、ResourceLoaderAware、ApplicationEventPublisherAware、MessageSourceAware、ApplicationContextAware；注册已决定的依赖类型与对应的实现BeanFactory、ResourceLoader、ApplicationEventPublisher、ApplicationContext；添加后置处理ApplicationListenerDetector；注册各种环境单例：environment、systemProperties、systemEnvironment
5.  \_\_postProcessBeanFactory\_\_后置操作，目前是什么都不处理
6.  \_\_invokeBeanFactoryPostProcessors\_\_调用后置处理

protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
    	PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());
    	...
    }

> 1.  PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors，调用委派对象的后置处理，入参为应用上下文的beanFactoryPostProcessors后置处理
> 2.  如果入参后置处理对象为BeanDefinitionRegistryPostProcessor类型，回调 postProcessBeanDefinitionRegistry 后置处理，并添加至registryPostProcessors，否则放入regular集合中regularPostProcessors常规后置处理：Invoke BeanDefinitionRegistryPostProcessors first, if any.
> 3.  从工厂中获取BeanDefinitionRegistryPostProcessor类型bean名称，并且判断是否存在优先级（PriorityOrdered），存在则排序后放入registryPostProcessors中，调用 postProcessBeanDefinitionRegistry 后置处理：First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
> 
> > 1.  例如：ConfigurationClassPostProcessor处理逻辑
> > 2.  ConfigurationClassPostProcessor回调postProcessBeanDefinitionRegistry
> > 3.  processConfigBeanDefinitions，遍历当前工厂所有的bean定义，如果存在Configuration注解或者Component、ComponentScan、Import、ImportResource注解，并且没有被解析处理过，如果开启了debug日志，则打印日志，否则继续
> > 4.  校验是否存在AnnotationMetadata并且Configuration注解对象，存在则添加至configCandidates候选配置集合中
> > 5.  Return immediately if no @Configuration classes were found
> > 6.  如果localBeanNameGeneratorSet缓存中不存在该类名称生成器，则为componentScanBeanNameGenerator，importBeanNameGenerator设置为internalConfigurationBeanNameGenerator
> > 7.  parser.parse解析每一个配置的bean（不仅仅是Configuration注解的bean，而是所有bean定义）：Parse each @Configuration class
> > 8.  asSourceClass封装为SourceClass实例：Application入口为StandardAnnotationMetadata类型元数据（通过自省对象获取注解的类），其余为AnnotationMetadataReadingVisitor类型元数据，根据class类调用asSourceClass解析Configuration类：Recursively process the configuration class and its superclass hierarchy.
> > 9.  doProcessConfigurationClass执行处理解析配置类:processMemberClasses解析处理所有内部类、接口对象；Process any @PropertySource annotations处理PropertySource注解对象；Process any @ComponentScan annotations处理所有扫描路径下的Component注解对象（第一次为Application对象，如果basePackages为空集合则设置为当前对象所属包路径）；Process any @Import annotations处理所有import注解对象（importSelector返回选择要导入的对象集合遍历导入）；Process any @ImportResource annotations；Process individual @Bean methods处理sourceClass的bean注解以及sourceClass方法中存在bean注解的bean定义；Process default methods on interfaces递归遍历处理（处理逻辑同上一步Process individual @Bean methods）Application所有父接口类定义与方法如果存在bean注解添加至Application的BeanMethod（方法注入的bean）元数据中（StandardAnnotationMetadata注解，并且包含Bean注解的方法）；Process superclass, if any如果Application对象有父类则处理
> > 10. 配置类缓存在ConfigurationClassParser.configurationClasses等待加载bean定义

//processImports
    private void processImports(ConfigurationClass configClass, SourceClass currentSourceClass,
    		Collection<SourceClass> importCandidates, boolean checkForCircularImports) throws IOException {
    ...
    	for (SourceClass candidate : importCandidates) {
    		if (candidate.isAssignable(ImportSelector.class)) {
    			// Candidate class is an ImportSelector -> delegate to it to determine imports
    			Class<?> candidateClass = candidate.loadClass();
    			ImportSelector selector = BeanUtils.instantiateClass(candidateClass, ImportSelector.class);
    			ParserStrategyUtils.invokeAwareMethods(
    					selector, this.environment, this.resourceLoader, this.registry);
    			if (this.deferredImportSelectors != null && selector instanceof DeferredImportSelector) {
    				this.deferredImportSelectors.add(
    						new DeferredImportSelectorHolder(configClass, (DeferredImportSelector) selector));
    			}
    			else {
    			//返回import要导入的class名称列表，递归处理解析导入
    				String[] importClassNames = selector.selectImports(currentSourceClass.getMetadata());
    				Collection<SourceClass> importSourceClasses = asSourceClasses(importClassNames);
    				processImports(configClass, currentSourceClass, importSourceClasses, false);
    			}
    		}
    		else if (candidate.isAssignable(ImportBeanDefinitionRegistrar.class)) {
    			// Candidate class is an ImportBeanDefinitionRegistrar ->
    			// delegate to it to register additional bean definitions
    			Class<?> candidateClass = candidate.loadClass();
    			ImportBeanDefinitionRegistrar registrar =
    					BeanUtils.instantiateClass(candidateClass, ImportBeanDefinitionRegistrar.class);
    			ParserStrategyUtils.invokeAwareMethods(
    					registrar, this.environment, this.resourceLoader, this.registry);
    					//将注解指定的ImportBeanDefinitionRegistrar类添加至ConfigurationClass（configuration注解的类）对象的importBeanDefinitionRegistrars属性中
    					//在处理完当前ConfigurationClass导入后，reader（ConfigurationClassBeanDefinitionReader）再遍历ConfigurationClass的importBeanDefinitionRegistrars属性
    					//调用ImportBeanDefinitionRegistrar#registerBeanDefinitions将bean定义注入上下文
    			configClass.addImportBeanDefinitionRegistrar(registrar, currentSourceClass.getMetadata());
    		}
    		else {
    			// Candidate class not an ImportSelector or ImportBeanDefinitionRegistrar ->
    			// process it as an @Configuration class
    			this.importStack.registerImport(
    					currentSourceClass.getMetadata(), candidate.getMetadata().getClassName());
    			processConfigurationClass(candidate.asConfigClass(configClass));
    		}
    	}
    ...
    }

> > 1.  reader.loadBeanDefinitions：ConfigurationClassBeanDefinitionReader加载bean定义loadBeanDefinitions loadBeanDefinitionsForBeanMethod，loadBeanDefinitionsFromImportedResources，MapperScannerRegistrar加载mapper，ImportBeanDefinitionRegistrar加载Import

private void loadBeanDefinitionsFromRegistrars(Map<ImportBeanDefinitionRegistrar, AnnotationMetadata> registrars) {
    	for (Map.Entry<ImportBeanDefinitionRegistrar, AnnotationMetadata> entry : registrars.entrySet()) {
    		entry.getKey().registerBeanDefinitions(entry.getValue(), this.registry);
    	}
    }

> > 1.  postProcessBeanDefinitionRegistry处理完毕
> > 2.  ConfigurationClassPostProcessor得postProcessBeanFactory处理类似，但多出下面两个步骤
> > 3.  注册ImportRegistry作为一个Bean至工厂来支持ImportAware通知动作，Register the ImportRegistry as a bean in order to support ImportAware @Configuration classes
> > 4.  postProcessBeanFactory,显然不支持BeanDefinitionRegistryPostProcessor钩子方法，此时只需惰性地调用processConfigurationClasses，增强配置类enhanceConfigurationClasses，注册ImportAwareBeanPostProcessor至工厂后置处理
> 
> 1.  再次从工厂中获取BeanDefinitionRegistryPostProcessor类型bean名称，并且判断是否存在顺序（Ordered），存在则排序调用（排除之前回调过的） postProcessBeanDefinitionRegistry 后置处理：Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
> 2.  调用剩余BeanDefinitionRegistryPostProcessor的postProcessBeanDefinitionRegistry回调函数：Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear.
> 3.  registryPostProcessors，regularPostProcessors，回调集合中的beanFactoryPostProcessor
> 4.  从工厂中获取 BeanFactoryPostProcessor bean名称（排除之前回调过的），回调beanFactoryPostProcessor，同样的顺序，先调用PriorityOrdered类型的，其次Ordered类型的，最后普通的

1.  **registerBeanPostProcessors**
2.  **initMessageSource**
3.  **initApplicationEventMulticaster**
4.  **onRefresh**
5.  **registerListeners**  
    注册监听：registerListeners（ApplicationListener），获取上下文中的监听或者工厂中该类型的bean进行注册。注册之前发布的消息缓存在上下文中的earlyApplicationEvents，将这些消息广播至当前注册的监听
6.  **finishBeanFactoryInitialization**：完成初始化：初始化非懒惰初始化的Bean
7.  **finishRefresh**  
    发布上下文刷新完成事件：ContextRefreshedEvent
8.  **resetCommonCaches**
9.  **刷新完成**
10. afterRefresh SpringApplication刷新上下文后置动作
11. listeners.finished SpringApplication监听器广播完成事件

#### 上下文获取Bean ApplicationContext.getBean 同XML配置：[spring XML 刷新上下文][spring XML 1] ####

[spring XML]: https://www.yuque.com/huihuixiangdehuiji/technology/rvb5tz
[spring XML 1]: https://blog.csdn.net/u010597819/article/details/86646191