Spring上下文

04177ba3 · SunWei峰 · 307c9ae2 · 04177ba3 · 04177ba3
Commit 04177ba3 authored Aug 17, 2022 by SunWei峰
2 changed files
--- a/spring-framework-main/spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java
+++ b/spring-framework-main/spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java
@@ -124,7 +124,6 @@ import org.springframework.util.ReflectionUtils;
 * @author Sam Brannen
 * @author Sebastien Deleuze
 * @author Brian Clozel
- * @since January 21, 2001
 * @see #refreshBeanFactory
 * @see #getBeanFactory
 * @see org.springframework.beans.factory.config.BeanFactoryPostProcessor
@@ -132,6 +131,7 @@ import org.springframework.util.ReflectionUtils;
 * @see org.springframework.context.event.ApplicationEventMulticaster
 * @see org.springframework.context.ApplicationListener
 * @see org.springframework.context.MessageSource
+ * @since January 21, 2001
 */
 public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		implements ConfigurableApplicationContext {
@@ -139,6 +139,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Name of the MessageSource bean in the factory.
 	 * If none is supplied, message resolution is delegated to the parent.
+	 *
 	 * @see MessageSource
 	 */
 	public static final String MESSAGE_SOURCE_BEAN_NAME = "messageSource";
@@ -146,6 +147,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Name of the LifecycleProcessor bean in the factory.
 	 * If none is supplied, a DefaultLifecycleProcessor is used.
+	 *
 	 * @see org.springframework.context.LifecycleProcessor
 	 * @see org.springframework.context.support.DefaultLifecycleProcessor
 	 */
@@ -154,6 +156,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Name of the ApplicationEventMulticaster bean in the factory.
 	 * If none is supplied, a default SimpleApplicationEventMulticaster is used.
+	 *
 	 * @see org.springframework.context.event.ApplicationEventMulticaster
 	 * @see org.springframework.context.event.SimpleApplicationEventMulticaster
 	 */
@@ -174,68 +177,106 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	}
-	/** Logger used by this class. Available to subclasses. */
+	/**
+	 * Logger used by this class. Available to subclasses.
+	 */
 	protected final Log logger = LogFactory.getLog(getClass());
-	/** Unique id for this context, if any. */
+	/**
+	 * Unique id for this context, if any.
+	 */
 	private String id = ObjectUtils.identityToString(this);
-	/** Display name. */
+	/**
+	 * Display name.
+	 */
 	private String displayName = ObjectUtils.identityToString(this);
-	/** Parent context. */
+	/**
+	 * Parent context.
+	 */
 	@Nullable
 	private ApplicationContext parent;
-	/** Environment used by this context. */
+	/**
+	 * Environment used by this context.
+	 */
 	@Nullable
 	private ConfigurableEnvironment environment;
-	/** BeanFactoryPostProcessors to apply on refresh. */
+	/**
+	 * BeanFactoryPostProcessors to apply on refresh.
+	 */
 	private final List<BeanFactoryPostProcessor> beanFactoryPostProcessors = new ArrayList<>();
-	/** System time in milliseconds when this context started. */
+	/**
+	 * System time in milliseconds when this context started.
+	 */
 	private long startupDate;
-	/** Flag that indicates whether this context is currently active. */
+	/**
+	 * Flag that indicates whether this context is currently active.
+	 */
 	private final AtomicBoolean active = new AtomicBoolean();
-	/** Flag that indicates whether this context has been closed already. */
+	/**
+	 * Flag that indicates whether this context has been closed already.
+	 */
 	private final AtomicBoolean closed = new AtomicBoolean();
-	/** Synchronization monitor for the "refresh" and "destroy". */
+	/**
+	 * Synchronization monitor for the "refresh" and "destroy".
+	 */
 	private final Object startupShutdownMonitor = new Object();
-	/** Reference to the JVM shutdown hook, if registered. */
+	/**
+	 * Reference to the JVM shutdown hook, if registered.
+	 */
 	@Nullable
 	private Thread shutdownHook;
-	/** ResourcePatternResolver used by this context. */
+	/**
+	 * ResourcePatternResolver used by this context.
+	 */
 	private final ResourcePatternResolver resourcePatternResolver;
-	/** LifecycleProcessor for managing the lifecycle of beans within this context. */
+	/**
+	 * LifecycleProcessor for managing the lifecycle of beans within this context.
+	 */
 	@Nullable
 	private LifecycleProcessor lifecycleProcessor;
-	/** MessageSource we delegate our implementation of this interface to. */
+	/**
+	 * MessageSource we delegate our implementation of this interface to.
+	 */
 	@Nullable
 	private MessageSource messageSource;
-	/** Helper class used in event publishing. */
+	/**
+	 * Helper class used in event publishing.
+	 */
 	@Nullable
 	private ApplicationEventMulticaster applicationEventMulticaster;
-	/** Application startup metrics. **/
+	/**
+	 * Application startup metrics.
+	 **/
 	private ApplicationStartup applicationStartup = ApplicationStartup.DEFAULT;
-	/** Statically specified listeners. */
+	/**
+	 * Statically specified listeners.
+	 */
 	private final Set<ApplicationListener<?>> applicationListeners = new LinkedHashSet<>();
-	/** Local listeners registered before refresh. */
+	/**
+	 * Local listeners registered before refresh.
+	 */
 	@Nullable
 	private Set<ApplicationListener<?>> earlyApplicationListeners;
-	/** ApplicationEvents published before the multicaster setup. */
+	/**
+	 * ApplicationEvents published before the multicaster setup.
+	 */
 	@Nullable
 	private Set<ApplicationEvent> earlyApplicationEvents;
@@ -249,6 +290,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Create a new AbstractApplicationContext with the given parent context.
+	 *
 	 * @param parent the parent context
 	 */
 	public AbstractApplicationContext(@Nullable ApplicationContext parent) {
@@ -265,6 +307,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * Set the unique id of this application context.
 	 * <p>Default is the object id of the context instance, or the name
 	 * of the context bean if the context is itself defined as a bean.
+	 *
 	 * @param id the unique id of the context
 	 */
 	@Override
@@ -294,6 +337,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Return a friendly name for this context.
+	 *
 	 * @return a display name for this context (never {@code null})
 	 */
 	@Override
@@ -317,6 +361,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * default with this method is one option but configuration through {@link
 	 * #getEnvironment()} should also be considered. In either case, such modifications
 	 * should be performed <em>before</em> {@link #refresh()}.
+	 *
 	 * @see org.springframework.context.support.AbstractApplicationContext#createEnvironment
 	 */
 	@Override
@@ -350,6 +395,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Return this context's internal bean factory as AutowireCapableBeanFactory,
 	 * if already available.
+	 *
 	 * @see #getBeanFactory()
 	 */
 	@Override
@@ -370,6 +416,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * <p>Note: Listeners get initialized after the MessageSource, to be able
 	 * to access it within listener implementations. Thus, MessageSource
 	 * implementations cannot publish events.
+	 *
 	 * @param event the event to publish (may be application-specific or a
 	 *              standard framework event)
 	 */
@@ -383,6 +430,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * <p>Note: Listeners get initialized after the MessageSource, to be able
 	 * to access it within listener implementations. Thus, MessageSource
 	 * implementations cannot publish events.
+	 *
 	 * @param event the event to publish (may be an {@link ApplicationEvent}
 	 *              or a payload object to be turned into a {@link PayloadApplicationEvent})
 	 */
@@ -393,6 +441,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Publish the given event to all listeners.
+	 *
 	 * @param event     the event to publish (may be an {@link ApplicationEvent}
 	 *                  or a payload object to be turned into a {@link PayloadApplicationEvent})
 	 * @param eventType the resolved event type, if known
@@ -405,8 +454,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		ApplicationEvent applicationEvent;
 		if (event instanceof ApplicationEvent) {
 			applicationEvent = (ApplicationEvent) event;
-		}
+		} else {
-		else {
 			applicationEvent = new PayloadApplicationEvent<>(this, event, eventType);
 			if (eventType == null) {
 				eventType = ((PayloadApplicationEvent<?>) applicationEvent).getResolvableType();
@@ -416,8 +464,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		// Multicast right now if possible - or lazily once the multicaster is initialized
 		if (this.earlyApplicationEvents != null) {
 			this.earlyApplicationEvents.add(applicationEvent);
-		}
+		} else {
-		else {
 			getApplicationEventMulticaster().multicastEvent(applicationEvent, eventType);
 		}
@@ -425,8 +472,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		if (this.parent != null) {
 			if (this.parent instanceof AbstractApplicationContext) {
 				((AbstractApplicationContext) this.parent).publishEvent(event, eventType);
-			}
+			} else {
-			else {
 				this.parent.publishEvent(event);
 			}
 		}
@@ -434,6 +480,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Return the internal ApplicationEventMulticaster used by the context.
+	 *
 	 * @return the internal ApplicationEventMulticaster (never {@code null})
 	 * @throws IllegalStateException if the context has not been initialized yet
 	 */
@@ -458,6 +505,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Return the internal LifecycleProcessor used by the context.
+	 *
 	 * @return the internal LifecycleProcessor (never {@code null})
 	 * @throws IllegalStateException if the context has not been initialized yet
 	 */
@@ -479,6 +527,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * <p><b>Do not call this when needing to resolve a location pattern.</b>
 	 * Call the context's {@code getResources} method instead, which
 	 * will delegate to the ResourcePatternResolver.
+	 *
 	 * @return the ResourcePatternResolver for this context
 	 * @see #getResources
 	 * @see org.springframework.core.io.support.PathMatchingResourcePatternResolver
@@ -498,6 +547,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * {@linkplain ConfigurableEnvironment#merge(ConfigurableEnvironment) merged} with
 	 * this (child) application context environment if the parent is non-{@code null} and
 	 * its environment is an instance of {@link ConfigurableEnvironment}.
+	 *
 	 * @see ConfigurableEnvironment#merge(ConfigurableEnvironment)
 	 */
 	@Override
@@ -594,9 +644,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 				// 12，完成刷新过程， 通知生命周期处理器 LifecycleProcessor 刷新过程同时发出 ContextRefreshEvent通知别人
 				finishRefresh();
-			}
+			} catch (BeansException ex) {
-			catch (BeansException ex) {
 				if (logger.isWarnEnabled()) {
 					logger.warn("Exception encountered during context initialization - " +
 							"cancelling refresh attempt: " + ex);
@@ -610,9 +658,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 				// Propagate exception to caller.
 				throw ex;
-			}
+			} finally {
-			finally {
 				// Reset common introspection caches in Spring's core, since we
 				// might not ever need metadata for singleton beans anymore...
 				resetCommonCaches();
@@ -634,8 +680,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		if (logger.isDebugEnabled()) {
 			if (logger.isTraceEnabled()) {
 				logger.trace("Refreshing " + this);
-			}
+			} else {
-			else {
 				logger.debug("Refreshing " + getDisplayName());
 			}
 		}
@@ -651,8 +696,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		// Store pre-refresh ApplicationListeners...
 		if (this.earlyApplicationListeners == null) {
 			this.earlyApplicationListeners = new LinkedHashSet<>(this.applicationListeners);
-		}
+		} else {
-		else {
 			// Reset local application listeners to pre-refresh state.
 			this.applicationListeners.clear();
 			this.applicationListeners.addAll(this.earlyApplicationListeners);
@@ -665,6 +709,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * <p>Replace any stub property sources with actual instances.
+	 *
 	 * @see org.springframework.core.env.PropertySource.StubPropertySource
 	 * @see org.springframework.web.context.support.WebApplicationContextUtils#initServletPropertySources
 	 */
@@ -674,6 +719,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Tell the subclass to refresh the internal bean factory.
+	 *
 	 * @return the fresh BeanFactory instance
 	 * @see #refreshBeanFactory()
 	 * @see #getBeanFactory()
@@ -688,6 +734,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * 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) {
@@ -757,6 +804,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * initialization. All bean definitions will have been loaded, but no beans
 	 * will have been instantiated yet. This allows for registering special
 	 * BeanPostProcessors etc in certain ApplicationContext implementations.
+	 *
 	 * @param beanFactory the bean factory used by the application context
 	 */
 	protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
@@ -785,6 +833,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * <p>Must be called before any instantiation of application beans.
 	 */
 	protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
+		// 开始注册 BeanPostProcessor
 		PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
 	}
@@ -807,8 +856,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 			if (logger.isTraceEnabled()) {
 				logger.trace("Using MessageSource [" + this.messageSource + "]");
 			}
-		}
+		} else {
-		else {
 			// Use empty MessageSource to be able to accept getMessage calls.
 			DelegatingMessageSource dms = new DelegatingMessageSource();
 			dms.setParentMessageSource(getInternalParentMessageSource());
@@ -823,19 +871,25 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Initialize the ApplicationEventMulticaster.
 	 * Uses SimpleApplicationEventMulticaster if none defined in the context.
+	 *
 	 * @see org.springframework.context.event.SimpleApplicationEventMulticaster
 	 */
 	protected void initApplicationEventMulticaster() {
+		// 作用就是就是将事件通知给监听者
 		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
+		// 当前是否包含了名为 applicationEventMulticaster 的事件多播器bean注入
 		if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
+			// 若存在，则实例化该多播器，并赋值给 applicationEventMulticaster 变量
 			this.applicationEventMulticaster =
 					beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
 			if (logger.isTraceEnabled()) {
 				logger.trace("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
 			}
 		}
+		// 若不存在，构造一个 SimpleApplicationEventMulticaster 多播器对象，并赋值给applicationEventMulticaster 变量
 		else {
 			this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
+			// 将该对象注入bean工厂
 			beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
 			if (logger.isTraceEnabled()) {
 				logger.trace("No '" + APPLICATION_EVENT_MULTICASTER_BEAN_NAME + "' bean, using " +
@@ -847,6 +901,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Initialize the LifecycleProcessor.
 	 * Uses DefaultLifecycleProcessor if none defined in the context.
+	 *
 	 * @see org.springframework.context.support.DefaultLifecycleProcessor
 	 */
 	protected void initLifecycleProcessor() {
@@ -857,8 +912,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 			if (logger.isTraceEnabled()) {
 				logger.trace("Using LifecycleProcessor [" + this.lifecycleProcessor + "]");
 			}
-		}
+		} else {
-		else {
 			DefaultLifecycleProcessor defaultProcessor = new DefaultLifecycleProcessor();
 			defaultProcessor.setBeanFactory(beanFactory);
 			this.lifecycleProcessor = defaultProcessor;
@@ -874,6 +928,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * Template method which can be overridden to add context-specific refresh work.
 	 * Called on initialization of special beans, before instantiation of singletons.
 	 * <p>This implementation is empty.
+	 *
 	 * @throws BeansException in case of errors
 	 * @see #refresh()
 	 */
@@ -887,12 +942,14 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 */
 	protected void registerListeners() {
 		// Register statically specified listeners first.
+		// 硬编码方式注册
 		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!
+		// 配置文件方式注册
 		String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);
 		for (String listenerBeanName : listenerBeanNames) {
 			getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
@@ -914,6 +971,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 */
 	protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
 		// Initialize conversion service for this context.
+		// 1.初始化此上下文的转换服务
 		if (beanFactory.containsBean(CONVERSION_SERVICE_BEAN_NAME) &&
 				beanFactory.isTypeMatch(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)) {
 			beanFactory.setConversionService(
@@ -923,6 +981,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		// Register a default embedded value resolver if no BeanFactoryPostProcessor
 		// (such as a PropertySourcesPlaceholderConfigurer bean) registered any before:
 		// at this point, primarily for resolution in annotation attribute values.
+		// 2.如果beanFactory之前没有注册嵌入值解析器，则注册默认的嵌入值解析器：主要用于注解属性值的解析。
 		if (!beanFactory.hasEmbeddedValueResolver()) {
 			beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal));
 		}
@@ -966,6 +1025,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Cancel this context's refresh attempt, resetting the {@code active} flag
 	 * after an exception got thrown.
+	 *
 	 * @param ex the exception that led to the cancellation
 	 */
 	protected void cancelRefresh(BeansException ex) {
@@ -976,11 +1036,12 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * Reset Spring's common reflection metadata caches, in particular the
 	 * {@link ReflectionUtils}, {@link AnnotationUtils}, {@link ResolvableType}
 	 * and {@link CachedIntrospectionResults} caches.
-	 * @since 4.2
+	 *
 	 * @see ReflectionUtils#clearCache()
 	 * @see AnnotationUtils#clearCache()
 	 * @see ResolvableType#clearCache()
 	 * @see CachedIntrospectionResults#clearClassLoader(ClassLoader)
+	 * @since 4.2
 	 */
 	protected void resetCommonCaches() {
 		ReflectionUtils.clearCache();
@@ -995,6 +1056,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * {@code SpringContextShutdownHook} with the JVM runtime, closing this
 	 * context on JVM shutdown unless it has already been closed at that time.
 	 * <p>Delegates to {@code doClose()} for the actual closing procedure.
+	 *
 	 * @see Runtime#addShutdownHook
 	 * @see ConfigurableApplicationContext#SHUTDOWN_HOOK_THREAD_NAME
 	 * @see #close()
@@ -1020,6 +1082,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * Close this application context, destroying all beans in its bean factory.
 	 * <p>Delegates to {@code doClose()} for the actual closing procedure.
 	 * Also removes a JVM shutdown hook, if registered, as it's not needed anymore.
+	 *
 	 * @see #doClose()
 	 * @see #registerShutdownHook()
 	 */
@@ -1032,8 +1095,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 			if (this.shutdownHook != null) {
 				try {
 					Runtime.getRuntime().removeShutdownHook(this.shutdownHook);
-				}
+				} catch (IllegalStateException ex) {
-				catch (IllegalStateException ex) {
 					// ignore - VM is already shutting down
 				}
 			}
@@ -1044,6 +1106,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * Actually performs context closing: publishes a ContextClosedEvent and
 	 * destroys the singletons in the bean factory of this application context.
 	 * <p>Called by both {@code close()} and a JVM shutdown hook, if any.
+	 *
 	 * @see org.springframework.context.event.ContextClosedEvent
 	 * @see #destroyBeans()
 	 * @see #close()
@@ -1060,8 +1123,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 			try {
 				// Publish shutdown event.
 				publishEvent(new ContextClosedEvent(this));
-			}
+			} catch (Throwable ex) {
-			catch (Throwable ex) {
 				logger.warn("Exception thrown from ApplicationListener handling ContextClosedEvent", ex);
 			}
@@ -1069,8 +1131,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 			if (this.lifecycleProcessor != null) {
 				try {
 					this.lifecycleProcessor.onClose();
-				}
+				} catch (Throwable ex) {
-				catch (Throwable ex) {
 					logger.warn("Exception thrown from LifecycleProcessor on context close", ex);
 				}
 			}
@@ -1103,6 +1164,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * <p>Can be overridden to add context-specific bean destruction steps
 	 * right before or right after standard singleton destruction,
 	 * while the context's BeanFactory is still active.
+	 *
 	 * @see #getBeanFactory()
 	 * @see org.springframework.beans.factory.config.ConfigurableBeanFactory#destroySingletons()
 	 */
@@ -1140,8 +1202,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		if (!this.active.get()) {
 			if (this.closed.get()) {
 				throw new IllegalStateException(getDisplayName() + " has been closed already");
-			}
+			} else {
-			else {
 				throw new IllegalStateException(getDisplayName() + " has not been refreshed yet");
 			}
 		}
@@ -1364,6 +1425,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Return the internal bean factory of the parent context if it implements
 	 * ConfigurableApplicationContext; else, return the parent context itself.
+	 *
 	 * @see org.springframework.context.ConfigurableApplicationContext#getBeanFactory
 	 */
 	@Nullable
@@ -1394,6 +1456,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	/**
 	 * Return the internal MessageSource used by the context.
+	 *
 	 * @return the internal MessageSource (never {@code null})
 	 * @throws IllegalStateException if the context has not been initialized yet
 	 */
@@ -1458,6 +1521,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * <p>A subclass will either create a new bean factory and hold a reference to it,
 	 * or return a single BeanFactory instance that it holds. In the latter case, it will
 	 * usually throw an IllegalStateException if refreshing the context more than once.
+	 *
 	 * @throws BeansException        if initialization of the bean factory failed
 	 * @throws IllegalStateException if already initialized and multiple refresh
 	 *                               attempts are not supported
@@ -1477,6 +1541,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	 * <p>Note: Subclasses should check whether the context is still active before
 	 * returning the internal bean factory. The internal factory should generally be
 	 * considered unavailable once the context has been closed.
+	 *
 	 * @return this application context's internal bean factory (never {@code null})
 	 * @throws IllegalStateException if the context does not hold an internal bean factory yet
 	 *                               (usually if {@link #refresh()} has never been called) or if the context has been

--- a/spring-framework-main/spring-context/src/main/java/org/springframework/context/support/PostProcessorRegistrationDelegate.java
+++ b/spring-framework-main/spring-context/src/main/java/org/springframework/context/support/PostProcessorRegistrationDelegate.java
@@ -175,7 +175,7 @@ final class PostProcessorRegistrationDelegate {
 			// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
 			// 6.调用所有 BeanDefinitionRegistryPostProcessor 的 postProcessBeanFactory 方法
-			// (BeanDefinitionRegistryPostProcessor继承自BeanFactoryPostProcessor)
+			// (BeanDefinitionRegistryPostProcessor 继承自 BeanFactoryPostProcessor)
 			invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
 			// 7.最后, 调用入参 beanFactoryPostProcessors 中的普通 BeanFactoryPostProcessor 的 postProcessBeanFactory 方法
 			invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
@@ -263,20 +263,27 @@ final class PostProcessorRegistrationDelegate {
 		// to ensure that your proposal does not result in a breaking change:
 		// https://github.com/spring-projects/spring-framework/issues?q=PostProcessorRegistrationDelegate+is%3Aclosed+label%3A%22status%3A+declined%22
+		// 1.找出所有实现BeanPostProcessor接口的类
 		String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
-		// Register BeanPostProcessorChecker that logs an info message when
+		// BeanPostProcessorChecker 是一个普通的信息打印，可能会有些情况，
-		// a bean is created during BeanPostProcessor instantiation, i.e. when
+		// 当Spring中的后置处理器还没有被注册就已经开始了bean的初始化时，
-		// a bean is not eligible for getting processed by all BeanPostProcessors.
+		// 便会打印 BeanPostProcessorChecker 中的信息
+		// BeanPostProcessor的目标计数
 		int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
+		// 2.添加BeanPostProcessorChecker(主要用于记录信息)到beanFactory中
 		beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
-		// Separate between BeanPostProcessors that implement PriorityOrdered,
+		// 3.定义不同的变量用于区分:
-		// Ordered, and the rest.
+		// 实现PriorityOrdered接口的BeanPostProcessor、实现Ordered接口的BeanPostProcessor、普通BeanPostProcessor
+		// 第一个是对象链表，第二三个是 beanName链表
+		// 用于存放实现PriorityOrdered接口的BeanPostProcessor
 		List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
+		// 用于存放Spring内部的BeanPostProcessor
 		List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();
 		List<String> orderedPostProcessorNames = new ArrayList<>();
 		List<String> nonOrderedPostProcessorNames = new ArrayList<>();
+		// 4.遍历 postProcessorNames, 将 BeanPostProcessors分开
 		for (String ppName : postProcessorNames) {
 			if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
 				BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
@@ -321,11 +328,13 @@ final class PostProcessorRegistrationDelegate {
 		registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
 		// Finally, re-register all internal BeanPostProcessors.
+		// 重新注册内部PostProcessors，（相当于内部的BeanPostProcessor会被移到处理器链的末尾）
 		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).
+		// 重新注册 ApplicationListenerDetector（跟上面类似，主要是为了移动到处理器链的末尾）
 		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
 	}