spring注解开发(七) 容器创建过程
传入配置类后,
注册配置类,主要是 refresh()
public void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { // Prepare this context for refreshing. prepareRefresh(); // Tell the subclass to refresh the internal bean factory. ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); // Prepare the bean factory for use in this context. prepareBeanFactory(beanFactory); try { // Allows post-processing of the bean factory in context subclasses. postProcessBeanFactory(beanFactory); // Invoke factory processors registered as beans in the context. invokeBeanFactoryPostProcessors(beanFactory); // Register bean processors that intercept bean creation. registerBeanPostProcessors(beanFactory); // Initialize message source for this context. initMessageSource(); // Initialize event multicaster for this context. initApplicationEventMulticaster(); // Initialize other special beans in specific context subclasses. onRefresh(); // Check for listener beans and register them. registerListeners(); // Instantiate all remaining (non-lazy-init) singletons. finishBeanFactoryInitialization(beanFactory); // Last step: publish corresponding event. finishRefresh(); } catch (BeansException ex) { if (logger.isWarnEnabled()) { logger.warn("Exception encountered during context initialization - " + "cancelling refresh attempt: " + ex); } // Destroy already created singletons to avoid dangling resources. destroyBeans(); // Reset 'active' flag. cancelRefresh(ex); // Propagate exception to caller. throw ex; } finally { // Reset common introspection caches in Spring's core, since we // might not ever need metadata for singleton beans anymore... resetCommonCaches(); } } }
prepareRefresh();
记录一下日期,设置一些状态,初始化一些属性并校验,准备收集一些早期事件,一旦有了multicaster就发布等等
obtainFreshBeanFactory();
创建之后返回beanFactory
prepareBeanFactory(beanFactory); beanFactory的预处理工作
/** * Configure the factory's standard context characteristics, * such as the context's ClassLoader and post-processors. * @param beanFactory the BeanFactory to configure */ protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) { // Tell the internal bean factory to use the context's class loader etc. beanFactory.setBeanClassLoader(getClassLoader()); beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader())); beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment())); // Configure the bean factory with context callbacks. beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this)); beanFactory.ignoreDependencyInterface(EnvironmentAware.class); beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class); beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class); beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class); beanFactory.ignoreDependencyInterface(MessageSourceAware.class); beanFactory.ignoreDependencyInterface(ApplicationContextAware.class); // BeanFactory interface not registered as resolvable type in a plain factory. // MessageSource registered (and found for autowiring) as a bean. beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory); beanFactory.registerResolvableDependency(ResourceLoader.class, this); beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this); beanFactory.registerResolvableDependency(ApplicationContext.class, this); // Register early post-processor for detecting inner beans as ApplicationListeners. beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this)); // Detect a LoadTimeWeaver and prepare for weaving, if found. if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) { beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory)); // Set a temporary ClassLoader for type matching. beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader())); } // Register default environment beans. if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) { beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment()); } if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) { beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties()); } if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) { beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment()); } }
postProcessBeanFactory(beanFactory);
invokeBeanFactoryPostProcessors(beanFactory);
BeanFactoryPostProcessors 是对 BeanFactory已经初始化之后做一些处理
public static void invokeBeanFactoryPostProcessors( ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) { // Invoke BeanDefinitionRegistryPostProcessors first, if any. Set<String> processedBeans = new HashSet<>(); if (beanFactory instanceof BeanDefinitionRegistry) { BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory; List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>(); List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>(); for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) { if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) { BeanDefinitionRegistryPostProcessor registryProcessor = (BeanDefinitionRegistryPostProcessor) postProcessor; registryProcessor.postProcessBeanDefinitionRegistry(registry); registryProcessors.add(registryProcessor); } else { regularPostProcessors.add(postProcessor); } } // Do not initialize FactoryBeans here: We need to leave all regular beans // uninitialized to let the bean factory post-processors apply to them! // Separate between BeanDefinitionRegistryPostProcessors that implement // PriorityOrdered, Ordered, and the rest. List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>(); // First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered. String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); for (String ppName : postProcessorNames) { if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class)); processedBeans.add(ppName); } } sortPostProcessors(currentRegistryProcessors, beanFactory); registryProcessors.addAll(currentRegistryProcessors); invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); currentRegistryProcessors.clear(); // Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered. postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); for (String ppName : postProcessorNames) { if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) { currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class)); processedBeans.add(ppName); } } sortPostProcessors(currentRegistryProcessors, beanFactory); registryProcessors.addAll(currentRegistryProcessors); invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); currentRegistryProcessors.clear(); // Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear. boolean reiterate = true; while (reiterate) { reiterate = false; postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); for (String ppName : postProcessorNames) { if (!processedBeans.contains(ppName)) { currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class)); processedBeans.add(ppName); reiterate = true; } } sortPostProcessors(currentRegistryProcessors, beanFactory); registryProcessors.addAll(currentRegistryProcessors); invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); currentRegistryProcessors.clear(); } // Now, invoke the postProcessBeanFactory callback of all processors handled so far. invokeBeanFactoryPostProcessors(registryProcessors, beanFactory); invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory); } else { // Invoke factory processors registered with the context instance. invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory); } // Do not initialize FactoryBeans here: We need to leave all regular beans // uninitialized to let the bean factory post-processors apply to them! String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false); // Separate between BeanFactoryPostProcessors that implement PriorityOrdered, // Ordered, and the rest. List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>(); List<String> orderedPostProcessorNames = new ArrayList<>(); List<String> nonOrderedPostProcessorNames = new ArrayList<>(); for (String ppName : postProcessorNames) { if (processedBeans.contains(ppName)) { // skip - already processed in first phase above } else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class)); } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { orderedPostProcessorNames.add(ppName); } else { nonOrderedPostProcessorNames.add(ppName); } } // First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered. sortPostProcessors(priorityOrderedPostProcessors, beanFactory); invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory); // Next, invoke the BeanFactoryPostProcessors that implement Ordered. List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>(); for (String postProcessorName : orderedPostProcessorNames) { orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class)); } sortPostProcessors(orderedPostProcessors, beanFactory); invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory); // Finally, invoke all other BeanFactoryPostProcessors. List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>(); for (String postProcessorName : nonOrderedPostProcessorNames) { nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class)); } invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory); // Clear cached merged bean definitions since the post-processors might have // modified the original metadata, e.g. replacing placeholders in values... beanFactory.clearMetadataCache(); }
registerBeanPostProcessors(beanFactory); 注册 BeanPostProcessors
public static void registerBeanPostProcessors( ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) { String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false); // Register BeanPostProcessorChecker that logs an info message when // a bean is created during BeanPostProcessor instantiation, i.e. when // a bean is not eligible for getting processed by all BeanPostProcessors. int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length; beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount)); // Separate between BeanPostProcessors that implement PriorityOrdered, // Ordered, and the rest. List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>(); List<BeanPostProcessor> internalPostProcessors = new ArrayList<>(); List<String> orderedPostProcessorNames = new ArrayList<>(); List<String> nonOrderedPostProcessorNames = new ArrayList<>(); for (String ppName : postProcessorNames) { if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); priorityOrderedPostProcessors.add(pp); if (pp instanceof MergedBeanDefinitionPostProcessor) { internalPostProcessors.add(pp); } } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { orderedPostProcessorNames.add(ppName); } else { nonOrderedPostProcessorNames.add(ppName); } } // First, register the BeanPostProcessors that implement PriorityOrdered. sortPostProcessors(priorityOrderedPostProcessors, beanFactory); registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors); // Next, register the BeanPostProcessors that implement Ordered. List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>(); for (String ppName : orderedPostProcessorNames) { BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); orderedPostProcessors.add(pp); if (pp instanceof MergedBeanDefinitionPostProcessor) { internalPostProcessors.add(pp); } } sortPostProcessors(orderedPostProcessors, beanFactory); registerBeanPostProcessors(beanFactory, orderedPostProcessors); // Now, register all regular BeanPostProcessors. List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>(); for (String ppName : nonOrderedPostProcessorNames) { BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); nonOrderedPostProcessors.add(pp); if (pp instanceof MergedBeanDefinitionPostProcessor) { internalPostProcessors.add(pp); } } registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors); // Finally, re-register all internal BeanPostProcessors. sortPostProcessors(internalPostProcessors, beanFactory); registerBeanPostProcessors(beanFactory, internalPostProcessors); // Re-register post-processor for detecting inner beans as ApplicationListeners, // moving it to the end of the processor chain (for picking up proxies etc). beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext)); }
initMessageSource(); 国际化,消息绑定,消息解析
protected void initMessageSource() { ConfigurableListableBeanFactory beanFactory = getBeanFactory(); if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) { this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class); // Make MessageSource aware of parent MessageSource. if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) { HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource; if (hms.getParentMessageSource() == null) { // Only set parent context as parent MessageSource if no parent MessageSource // registered already. hms.setParentMessageSource(getInternalParentMessageSource()); } } if (logger.isDebugEnabled()) { logger.debug("Using MessageSource [" + this.messageSource + "]"); } } else { // Use empty MessageSource to be able to accept getMessage calls. DelegatingMessageSource dms = new DelegatingMessageSource(); dms.setParentMessageSource(getInternalParentMessageSource()); this.messageSource = dms; beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource); if (logger.isDebugEnabled()) { logger.debug("Unable to locate MessageSource with name '" + MESSAGE_SOURCE_BEAN_NAME + "': using default [" + this.messageSource + "]"); } } }
initApplicationEventMulticaster(); 初始化事件Multicaster
onRefresh();自容器在容器刷心的时候触发,自己定义
registerListeners();注册监听器
/** * Add beans that implement ApplicationListener as listeners. * Doesn't affect other listeners, which can be added without being beans. */ protected void registerListeners() { // Register statically specified listeners first. for (ApplicationListener<?> listener : getApplicationListeners()) { getApplicationEventMulticaster().addApplicationListener(listener); } // Do not initialize FactoryBeans here: We need to leave all regular beans // uninitialized to let post-processors apply to them! String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false); for (String listenerBeanName : listenerBeanNames) { getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName); } // Publish early application events now that we finally have a multicaster... Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents; this.earlyApplicationEvents = null; if (earlyEventsToProcess != null) { for (ApplicationEvent earlyEvent : earlyEventsToProcess) { getApplicationEventMulticaster().multicastEvent(earlyEvent); } } }
finishBeanFactoryInitialization(beanFactory); 完成剩下的还没初始化的bean
/** * Finish the initialization of this context's bean factory, * initializing all remaining singleton beans. */ protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) { // Initialize conversion service for this context. if (beanFactory.containsBean(CONVERSION_SERVICE_BEAN_NAME) && beanFactory.isTypeMatch(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)) { beanFactory.setConversionService( beanFactory.getBean(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)); } // Register a default embedded value resolver if no bean post-processor // (such as a PropertyPlaceholderConfigurer bean) registered any before: // at this point, primarily for resolution in annotation attribute values. if (!beanFactory.hasEmbeddedValueResolver()) { beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal)); } // Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early. String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false); for (String weaverAwareName : weaverAwareNames) { getBean(weaverAwareName); } // Stop using the temporary ClassLoader for type matching. beanFactory.setTempClassLoader(null); // Allow for caching all bean definition metadata, not expecting further changes. beanFactory.freezeConfiguration(); // Instantiate all remaining (non-lazy-init) singletons. beanFactory.preInstantiateSingletons(); }
finishRefresh(); 发布事件监听
Spring容器的refresh()【创建刷新】;
1、prepareRefresh()刷新前的预处理;
1)、initPropertySources()初始化一些属性设置;子类自定义个性化的属性设置方法;
2)、getEnvironment().validateRequiredProperties();检验属性的合法等
3)、earlyApplicationEvents= new LinkedHashSet<ApplicationEvent>();保存容器中的一些早期的事件;
2、obtainFreshBeanFactory();获取BeanFactory;
1)、refreshBeanFactory();刷新【创建】BeanFactory;
创建了一个this.beanFactory = new DefaultListableBeanFactory();
设置id;
2)、getBeanFactory();返回刚才GenericApplicationContext创建的BeanFactory对象;
3)、将创建的BeanFactory【DefaultListableBeanFactory】返回;
3、prepareBeanFactory(beanFactory);BeanFactory的预准备工作(BeanFactory进行一些设置);
1)、设置BeanFactory的类加载器、支持表达式解析器...
2)、添加部分BeanPostProcessor【ApplicationContextAwareProcessor】
3)、设置忽略的自动装配的接口EnvironmentAware、EmbeddedValueResolverAware、xxx;
4)、注册可以解析的自动装配;我们能直接在任何组件中自动注入:
BeanFactory、ResourceLoader、ApplicationEventPublisher、ApplicationContext
5)、添加BeanPostProcessor【ApplicationListenerDetector】
6)、添加编译时的AspectJ;
7)、给BeanFactory中注册一些能用的组件;
environment【ConfigurableEnvironment】、
systemProperties【Map<String, Object>】、
systemEnvironment【Map<String, Object>】
4、postProcessBeanFactory(beanFactory);BeanFactory准备工作完成后进行的后置处理工作;
1)、子类通过重写这个方法来在BeanFactory创建并预准备完成以后做进一步的设置
======================以上是BeanFactory的创建及预准备工作==================================
5、invokeBeanFactoryPostProcessors(beanFactory);执行BeanFactoryPostProcessor的方法;
BeanFactoryPostProcessor:BeanFactory的后置处理器。在BeanFactory标准初始化之后执行的;
两个接口:BeanFactoryPostProcessor、BeanDefinitionRegistryPostProcessor
1)、执行BeanFactoryPostProcessor的方法;
先执行BeanDefinitionRegistryPostProcessor
1)、获取所有的BeanDefinitionRegistryPostProcessor;
2)、看先执行实现了PriorityOrdered优先级接口的BeanDefinitionRegistryPostProcessor、
postProcessor.postProcessBeanDefinitionRegistry(registry)
3)、在执行实现了Ordered顺序接口的BeanDefinitionRegistryPostProcessor;
postProcessor.postProcessBeanDefinitionRegistry(registry)
4)、最后执行没有实现任何优先级或者是顺序接口的BeanDefinitionRegistryPostProcessors;
postProcessor.postProcessBeanDefinitionRegistry(registry)
再执行BeanFactoryPostProcessor的方法
1)、获取所有的BeanFactoryPostProcessor
2)、看先执行实现了PriorityOrdered优先级接口的BeanFactoryPostProcessor、
postProcessor.postProcessBeanFactory()
3)、在执行实现了Ordered顺序接口的BeanFactoryPostProcessor;
postProcessor.postProcessBeanFactory()
4)、最后执行没有实现任何优先级或者是顺序接口的BeanFactoryPostProcessor;
postProcessor.postProcessBeanFactory()
6、registerBeanPostProcessors(beanFactory);注册BeanPostProcessor(Bean的后置处理器)【 intercept bean creation】
不同接口类型的BeanPostProcessor;在Bean创建前后的执行时机是不一样的
BeanPostProcessor、
DestructionAwareBeanPostProcessor、
InstantiationAwareBeanPostProcessor、
SmartInstantiationAwareBeanPostProcessor、
MergedBeanDefinitionPostProcessor【internalPostProcessors】、
1)、获取所有的 BeanPostProcessor;后置处理器都默认可以通过PriorityOrdered、Ordered接口来执行优先级
2)、先注册PriorityOrdered优先级接口的BeanPostProcessor;
把每一个BeanPostProcessor;添加到BeanFactory中
beanFactory.addBeanPostProcessor(postProcessor);
3)、再注册Ordered接口的
4)、最后注册没有实现任何优先级接口的
5)、最终注册MergedBeanDefinitionPostProcessor;
6)、注册一个ApplicationListenerDetector;来在Bean创建完成后检查是否是ApplicationListener,如果是
applicationContext.addApplicationListener((ApplicationListener<?>) bean);
7、initMessageSource();初始化MessageSource组件(做国际化功能;消息绑定,消息解析);
1)、获取BeanFactory
2)、看容器中是否有id为messageSource的,类型是MessageSource的组件
如果有赋值给messageSource,如果没有自己创建一个DelegatingMessageSource;
MessageSource:取出国际化配置文件中的某个key的值;能按照区域信息获取;
3)、把创建好的MessageSource注册在容器中,以后获取国际化配置文件的值的时候,可以自动注入MessageSource;
beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource);
MessageSource.getMessage(String code, Object[] args, String defaultMessage, Locale locale);
8、initApplicationEventMulticaster();初始化事件派发器;
1)、获取BeanFactory
2)、从BeanFactory中获取applicationEventMulticaster的ApplicationEventMulticaster;
3)、如果上一步没有配置;创建一个SimpleApplicationEventMulticaster
4)、将创建的ApplicationEventMulticaster添加到BeanFactory中,以后其他组件直接自动注入
9、onRefresh();留给子容器(子类)
1、子类重写这个方法,在容器刷新的时候可以自定义逻辑;
10、registerListeners();给容器中将所有项目里面的ApplicationListener注册进来;
1、从容器中拿到所有的ApplicationListener
2、将每个监听器添加到事件派发器中;
getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
3、派发之前步骤产生的事件;
11、finishBeanFactoryInitialization(beanFactory);初始化所有剩下的单实例bean;
1、beanFactory.preInstantiateSingletons();初始化后剩下的单实例bean
1)、获取容器中的所有Bean,依次进行初始化和创建对象
2)、获取Bean的定义信息;RootBeanDefinition
3)、Bean不是抽象的,是单实例的,是懒加载;
1)、判断是否是FactoryBean;是否是实现FactoryBean接口的Bean;
2)、不是工厂Bean。利用getBean(beanName);创建对象
0、getBean(beanName); ioc.getBean();
1、doGetBean(name, null, null, false);
2、先获取缓存中保存的单实例Bean。如果能获取到说明这个Bean之前被创建过(所有创建过的单实例Bean都会被缓存起来)
从private final Map<String, Object> singletonObjects = new ConcurrentHashMap<String, Object>(256);获取的
3、缓存中获取不到,开始Bean的创建对象流程;
4、标记当前bean已经被创建
5、获取Bean的定义信息;
6、【获取当前Bean依赖的其他Bean;如果有按照getBean()把依赖的Bean先创建出来;】
7、启动单实例Bean的创建流程;
1)、createBean(beanName, mbd, args);
2)、Object bean = resolveBeforeInstantiation(beanName, mbdToUse);让BeanPostProcessor先拦截返回代理对象;
【InstantiationAwareBeanPostProcessor】:提前执行;
先触发:postProcessBeforeInstantiation();
如果有返回值:触发postProcessAfterInitialization();
3)、如果前面的InstantiationAwareBeanPostProcessor没有返回代理对象;调用4)
4)、Object beanInstance = doCreateBean(beanName, mbdToUse, args);创建Bean
1)、【创建Bean实例】;createBeanInstance(beanName, mbd, args);
利用工厂方法或者对象的构造器创建出Bean实例;
2)、applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName);
调用MergedBeanDefinitionPostProcessor的postProcessMergedBeanDefinition(mbd, beanType, beanName);
3)、【Bean属性赋值】populateBean(beanName, mbd, instanceWrapper);
赋值之前:
1)、拿到InstantiationAwareBeanPostProcessor后置处理器;
postProcessAfterInstantiation();
2)、拿到InstantiationAwareBeanPostProcessor后置处理器;
postProcessPropertyValues();
=====赋值之前:===
3)、应用Bean属性的值;为属性利用setter方法等进行赋值;
applyPropertyValues(beanName, mbd, bw, pvs);
4)、【Bean初始化】initializeBean(beanName, exposedObject, mbd);
1)、【执行Aware接口方法】invokeAwareMethods(beanName, bean);执行xxxAware接口的方法
BeanNameAware\BeanClassLoaderAware\BeanFactoryAware
2)、【执行后置处理器初始化之前】applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
BeanPostProcessor.postProcessBeforeInitialization();
3)、【执行初始化方法】invokeInitMethods(beanName, wrappedBean, mbd);
1)、是否是InitializingBean接口的实现;执行接口规定的初始化;
2)、是否自定义初始化方法;
4)、【执行后置处理器初始化之后】applyBeanPostProcessorsAfterInitialization
BeanPostProcessor.postProcessAfterInitialization();
5)、注册Bean的销毁方法;
5)、将创建的Bean添加到缓存中singletonObjects;
ioc容器就是这些Map;很多的Map里面保存了单实例Bean,环境信息。。。。;
所有Bean都利用getBean创建完成以后;
检查所有的Bean是否是SmartInitializingSingleton接口的;如果是;就执行afterSingletonsInstantiated();
12、finishRefresh();完成BeanFactory的初始化创建工作;IOC容器就创建完成;
1)、initLifecycleProcessor();初始化和生命周期有关的后置处理器;LifecycleProcessor
默认从容器中找是否有lifecycleProcessor的组件【LifecycleProcessor】;如果没有new DefaultLifecycleProcessor();
加入到容器;
写一个LifecycleProcessor的实现类,可以在BeanFactory
void onRefresh();
void onClose();
2)、 getLifecycleProcessor().onRefresh();
拿到前面定义的生命周期处理器(BeanFactory);回调onRefresh();
3)、publishEvent(new ContextRefreshedEvent(this));发布容器刷新完成事件;
4)、liveBeansView.registerApplicationContext(this);
======总结===========
1)、Spring容器在启动的时候,先会保存所有注册进来的Bean的定义信息;
1)、xml注册bean;<bean>
2)、注解注册Bean;@Service、@Component、@Bean、xxx
2)、Spring容器会合适的时机创建这些Bean
1)、用到这个bean的时候;利用getBean创建bean;创建好以后保存在容器中;
2)、统一创建剩下所有的bean的时候;finishBeanFactoryInitialization();
3)、后置处理器;BeanPostProcessor
1)、每一个bean创建完成,都会使用各种后置处理器进行处理;来增强bean的功能;
AutowiredAnnotationBeanPostProcessor:处理自动注入
AnnotationAwareAspectJAutoProxyCreator:来做AOP功能;
xxx....
增强的功能注解:
AsyncAnnotationBeanPostProcessor
....
4)、事件驱动模型;
ApplicationListener;事件监听;
ApplicationEventMulticaster;事件派发: