spring容器refresh方法源码分析(二)

spring容器refresh方法源码分析(一)接着前面讲:

文章目录

• registerBeanPostProcessors方法
• initMessageSource方法(不重要)
• initApplicationEventMulticaster初始化事件监听多路广播器(不重要)
• onRefresh 初始化子类的一些特殊的bean(在初始化单例bean之前)(不重要)
• registerListeners注册事件监听器

registerBeanPostProcessors方法

首先了解这个方法是注册BeanPostProcessor到spring容器,跟invokeBeanFactoryPostProcessors方法解析差不多,也可以通过PriorityOrdered,Ordered接口来调整优先级,不同的是invokeBeanFactoryPostProcessors会直接执行BeanFactoryPostProcessors的方法,而registerBeanPostProcessors仅仅是注册,BeanPostProcessors的两个方法,分别在spring创建bean的时候,执行初始化方法前,和在初始化方法后执行的:

public interface BeanPostProcessor {

	Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException;

	Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException;

}

源码:

protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
		PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
	}


public static void registerBeanPostProcessors(
			ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {

		//找出所有BeanPostProcessor的实现类
		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.
		//BeanPostProcessor的计数
		int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
		//添加BeanPostProcessorChecker到spring容器中(用于记录信息)
		beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

		// Separate between BeanPostProcessors that implement PriorityOrdered,
		// Ordered, and the rest.
		//前面分析过BeanFactoryPostProcessor,进行加载的时候会区分实现接口PriorityOrdered跟Ordered接口和没有实现接口的类
		//实现了PriorityOrdered接口的beanPostProcessor
		List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanPostProcessor>();
		//spring容器的beanPostProcessor
		List<BeanPostProcessor> internalPostProcessors = new ArrayList<BeanPostProcessor>();
		//实现了Ordered接口的beanPostProcessor
		List<String> orderedPostProcessorNames = new ArrayList<String>();
		//普通beanPostProcessor的名称
		List<String> nonOrderedPostProcessorNames = new ArrayList<String>();

		//遍历所有beanPostProcessor,进行区分
		for (String ppName : postProcessorNames) {
			// 实现了PriorityOrdered接口的BeanPostProcessor
			if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
				//拿到对应的BeanPostProcessor添加到priorityOrderedPostProcessors中
				BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
				priorityOrderedPostProcessors.add(pp);
				//如果也实现了MergedBeanDefinitionPostProcessor接口则添加到internalPostProcessors中
				if (pp instanceof MergedBeanDefinitionPostProcessor) {
					internalPostProcessors.add(pp);
				}
			}
			else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
				//实现Ordered接口,添加到orderedPostProcessorNames
				orderedPostProcessorNames.add(ppName);
			}
			else {
				//未实现Ordered接口的
				nonOrderedPostProcessorNames.add(ppName);
			}
		}

		// First, register the BeanPostProcessors that implement PriorityOrdered.
		//首先,对实现了PriorityOrdered的BeanPostProcessors进行排序,和注册
		sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
		registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);

		// Next, register the BeanPostProcessors that implement Ordered.
		//接下来注册实现Ordered接口的BeanPostProcessors
		List<BeanPostProcessor> orderedPostProcessors = new ArrayList<BeanPostProcessor>();
		for (String ppName : orderedPostProcessorNames) {
			BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
			orderedPostProcessors.add(pp);
			if (pp instanceof MergedBeanDefinitionPostProcessor) {
				// 如果ppName对应的Bean实例也实现了MergedBeanDefinitionPostProcessor接口,
				// 则将ppName对应的Bean实例添加到internalPostProcessors
				internalPostProcessors.add(pp);
			}
		}
		sortPostProcessors(orderedPostProcessors, beanFactory);
		registerBeanPostProcessors(beanFactory, orderedPostProcessors);

		// Now, register all regular BeanPostProcessors.
		//注册所有常规BeanPostProcessors
		List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanPostProcessor>();
		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.
		//最后, 重新注册所有内部BeanPostProcessors（相当于内部的BeanPostProcessor(实现了MergedBeanDefinitionPostProcessor)会被移到处理器链的末尾）
		sortPostProcessors(internalPostProcessors, beanFactory);
		// 注册internalPostProcessors
		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).
		// 重新注册ApplicationListenerDetector,放到处理链的最后
		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
	}

initMessageSource方法(不重要)

初始化当前 ApplicationContext 的 MessageSource，国际化等等;
了解一下即可源码:

protected void initMessageSource() {
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		//先判断是否有名称为messageSource的对象
		if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {
			this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);
			// Make MessageSource aware of parent MessageSource.
			//当父类Bean工厂不为空，并且这个bean对象是HierarchicalMessageSource类型
			if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) {
				HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;
				//设置父类MessageSource，此处设置内部的parent 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.
			//如果没有xml文件定义信息源对象，新建DelegatingMessageSource类作为messageSource的Bean
			//因为DelegatingMessageSource类实现了HierarchicalMessageSource接口，而这个接口继承了MessageSource这个类
			//因此实现了这个接口的类，都是MessageSource的子类，因此DelegatingMessageSource也是一个MessageSource
			DelegatingMessageSource dms = new DelegatingMessageSource();
			//给这个DelegatingMessageSource添加父类消息源
			dms.setParentMessageSource(getInternalParentMessageSource());
			this.messageSource = dms;
			//注册到工厂
			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初始化事件监听多路广播器(不重要)

也没啥讲的,就是往spring容器中初始化多播器;用来处理事件的分发(如,spring容器启动完成事件):

protected void initApplicationEventMulticaster() {
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		//首先判断spring容器中是否有定义了id为aplicationEventMulticaster的bean对象
		if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
			this.applicationEventMulticaster =
					beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
			if (logger.isDebugEnabled()) {
				logger.debug("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
			}
		}
		else {
			//没有就注册一个SimpleApplicationEventMulticaster
			this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
			beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
			if (logger.isDebugEnabled()) {
				logger.debug("Unable to locate ApplicationEventMulticaster with name '" +
						APPLICATION_EVENT_MULTICASTER_BEAN_NAME +
						"': using default [" + this.applicationEventMulticaster + "]");
			}
		}
	}

onRefresh 初始化子类的一些特殊的bean(在初始化单例bean之前)(不重要)

空方法,在具体子类中实现

registerListeners注册事件监听器

源码:

protected void registerListeners() {
		// Register statically specified listeners first.
		// 首先注册配置的监听器,注册到广播器
		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!
		// 获取所有的监听器的名称,设置到广播器
		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...
		// 发布早期应用事件
		Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
		this.earlyApplicationEvents = null;
		if (earlyEventsToProcess != null) {
			for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
				getApplicationEventMulticaster().multicastEvent(earlyEvent);
			}
		}
	}