Spring加载流程源码

一、从AbstractApplicationContext的体系说起

• 第一，从类结构设计上看， 围绕着是否需要Refresh容器衍生出两个抽象类：

AbstractRefreshableApplicationContext及子类无法做到GenericApplicationContext混合搭配从不同源头获取bean的定义信息

• 第二， 从加载的源来看（比如xml,groovy,annotation等）， 衍生出众多类型的ApplicationContext, 典型比如:

这里可以参考这篇文章

二、本文以ClassPathXmlApplicationContext为例，这种方式包含了多种spring加载bean的方式

//如下：开启spring应用
public static void main(String[] args) {
	ApplicationContext ac = 
			new ClassPathXmlApplicationContext("applicationContext.xml");
	User bean = ac.getBean("user",User.class);
	System.out.println(bean);
}

从ClassPathXmlApplicationContext的构造方法开始查看

public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, ApplicationContext parent)
		throws BeansException {
	// 1.初始化父类，这里一路加载到顶层父类AbstractApplicationContext中的构造方法
	// 才不再显示的super(parent)
	super(parent);
	// 2.设置本地的配置信息
	setConfigLocations(configLocations);
	// 3.完成Spring容器的初始化
	if (refresh) {
		refresh();
	}
}

1. super(parent)

public AbstractApplicationContext(ApplicationContext parent) {
	this();
	setParent(parent);
}

• 那么看一下this()

public AbstractApplicationContext() {
    //在该构造方法对resourcePatternResolver 变量赋值。resourcePatternResolver 的作用是根据路径得到类的Resource对象
	this.resourcePatternResolver = getResourcePatternResolver();
}

protected ResourcePatternResolver getResourcePatternResolver() {
//创建PathMatchingResourcePatternResolver对象的时候
//AbstractApplicationContext将自身作为ResourceLoader传递给了PathMatchingResourcePatternResolver
	return new PathMatchingResourcePatternResolver(this);
}

public PathMatchingResourcePatternResolver(ResourceLoader resourceLoader) {
	Assert.notNull(resourceLoader, "ResourceLoader must not be null");
	this.resourceLoader = resourceLoader;
}
@Override
public Resource getResource(String location) {
	return getResourceLoader().getResource(location);
}

• 再看一下setParent(parent)

@Override
public void setParent(ApplicationContext parent) {
	this.parent = parent; // null
	//因为parent为null所以if语句中的代码不会执行，所以此if中的代码在此逻辑中不会执行，所以在此就没有分析的必要了。
	//初始化的第一部分就分析完毕了，这部分的主要工作是为后续Resource处理准备好处理类
	if (parent != null) {
		Environment parentEnvironment = parent.getEnvironment();
		if (parentEnvironment instanceof ConfigurableEnvironment) {
			getEnvironment().merge((ConfigurableEnvironment) parentEnvironment);
		}
	}
}

2. setConfigLocations(configLocations)

//1.setConfigLocations主要工作有两个：创建环境对象ConfigurableEnvironment 、处理ClassPathXmlApplicationContext传入的字符串中的占位符；
//2.环境对象ConfigurableEnvironment中包含了当前JVM的profile配置信息、环境变量、 Java进程变量；
//3.处理占位符的关键是ConfigurableEnvironment、PropertyResolver、PropertyPlaceholderHelper之间的配合

public void setConfigLocations(String... locations) {
	if (locations != null) {
		Assert.noNullElements(locations, "Config locations must not be null");
		this.configLocations = new String[locations.length];
		for (int i = 0; i < locations.length; i++) {
			//循环取出每一个path参数，在此处我们就只有一个“applicationContext.xml“”
			this.configLocations[i] = resolvePath(locations[i]).trim();
		}
	}
	else {
		this.configLocations = null;
	}
}

// 这个方法的目的是替换掉path字符串中的占位符${XXX}这样的内容
protected String resolvePath(String path) {
     // 1.进入getEnvironment()
     // 2.进入resolveRequiredPlaceholders方法
	return getEnvironment().resolveRequiredPlaceholders(path);
}

• getEnvironment()：创建了ConfigurableEnvironment 对象

public ConfigurableEnvironment getEnvironment() {
	if (this.environment == null) {
		this.environment = createEnvironment();
	}
	return this.environment;
}

从提供的方法中可以看出两个功能

• PropertyResolver：resolveRequiredPlaceholders(path)
  

@Override
	public String resolveRequiredPlaceholders(String text) throws IllegalArgumentException {
		if (this.strictHelper == null) {
			this.strictHelper = createPlaceholderHelper(false);
		}
		return doResolvePlaceholders(text, this.strictHelper);
	}

处理占位符的方法：

• PropertyPlaceholderHelper

@Override
public String resolveRequiredPlaceholders(String text) throws IllegalArgumentException {
	if (this.strictHelper == null) {
		// 创建PropertyPlaceholderHelper对象
		this.strictHelper = createPlaceholderHelper(false);
	}
	return doResolvePlaceholders(text, this.strictHelper);
}

进入doResolvePlaceholders继续查看

private String doResolvePlaceholders(String text, PropertyPlaceholderHelper helper) {
	return helper.replacePlaceholders(text, new PropertyPlaceholderHelper.PlaceholderResolver() {
		@Override
		public String resolvePlaceholder(String placeholderName) {
			return getPropertyAsRawString(placeholderName);
		}
	});
}

getPropertyAsRawString的具体实现在PropertySourcesPropertyResolver类中

@Override
protected String getPropertyAsRawString(String key) {
	return getProperty(key, String.class, false);
}

继续跟踪helper.replacePlaceholders()，到了PropertyPlaceholderHelper.parseStringValue方法，这里面逐一找出每个占位符去做替换：

public String replacePlaceholders(String value, PlaceholderResolver placeholderResolver) {
	Assert.notNull(value, "'value' must not be null");
	return parseStringValue(value, placeholderResolver, new HashSet<String>());
}

parseStringValue方法中，找到了占位符后，会调用入参placeholderResolver的resolvePlaceholder(placeholder)方法，也就是上面匿名类的getPropertyAsRawString方法（实际上就是PropertySourcesPropertyResolver.getPropertyAsRawString方法），最终会在PropertySourcesPropertyResolver.getProperty方法中找出所有的属性来匹配占位符

protected String parseStringValue(
			String strVal, PlaceholderResolver placeholderResolver, Set<String> visitedPlaceholders) {
		StringBuilder result = new StringBuilder(strVal);
		int startIndex = strVal.indexOf(this.placeholderPrefix);
		while (startIndex != -1) {
			int endIndex = findPlaceholderEndIndex(result, startIndex);
			if (endIndex != -1) {
				String placeholder = result.substring(startIndex + this.placeholderPrefix.length(), endIndex);
				String originalPlaceholder = placeholder;
				if (!visitedPlaceholders.add(originalPlaceholder)) {
					throw new IllegalArgumentException(
							"Circular placeholder reference '" + originalPlaceholder + "' in property definitions");
				}
				// Recursive invocation, parsing placeholders contained in the placeholder key.
				placeholder = parseStringValue(placeholder, placeholderResolver, visitedPlaceholders);
				// Now obtain the value for the fully resolved key...
				String propVal = placeholderResolver.resolvePlaceholder(placeholder);
				if (propVal == null && this.valueSeparator != null) {
					int separatorIndex = placeholder.indexOf(this.valueSeparator);
					if (separatorIndex != -1) {
						String actualPlaceholder = placeholder.substring(0, separatorIndex);
						String defaultValue = placeholder.substring(separatorIndex + this.valueSeparator.length());
						propVal = placeholderResolver.resolvePlaceholder(actualPlaceholder);
						if (propVal == null) {
							propVal = defaultValue;
						}
					}
				}
				if (propVal != null) {
					// Recursive invocation, parsing placeholders contained in the
					// previously resolved placeholder value.
					propVal = parseStringValue(propVal, placeholderResolver, visitedPlaceholders);
					result.replace(startIndex, endIndex + this.placeholderSuffix.length(), propVal);
					if (logger.isTraceEnabled()) {
						logger.trace("Resolved placeholder '" + placeholder + "'");
					}
					startIndex = result.indexOf(this.placeholderPrefix, startIndex + propVal.length());
				}
				else if (this.ignoreUnresolvablePlaceholders) {
					// Proceed with unprocessed value.
					startIndex = result.indexOf(this.placeholderPrefix, endIndex + this.placeholderSuffix.length());
				}
				else {
					throw new IllegalArgumentException("Could not resolve placeholder '" +
							placeholder + "'" + " in string value \"" + strVal + "\"");
				}
				visitedPlaceholders.remove(originalPlaceholder);
			}
			else {
				startIndex = -1;
			}
		}
		return result.toString();
	}

总结：

剩下最核心的refresh()方法，单开一章

三、核心refresh()方法

public void refresh() throws BeansException, IllegalStateException {
		synchronized (this.startupShutdownMonitor) {
			//做容器刷新前的准备工作
			//1.设置容器的启动时间
			//2.设置活跃状态为true
			//3.设置关闭状态为false
			//4.获取Environment对象，并加载当前系统的属性值到Environment对象中
			//5.准备监听器和事件的集合对象，默认为空的集合
			prepareRefresh();
			//创建容器对象:DefaultListableFactory
			//加载xml配置文件的属性值到当前工厂中，最重要的就是BeanDefinition
			ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

			
			//beanFactory的准备工作，对各种属性进行填充
			prepareBeanFactory(beanFactory);
			try {
				// 允许在上下文子类中对 bean 工厂进行后处理。此处我们一般不做任何扩展工作
				postProcessBeanFactory(beanFactory);

				// 调用在上下文中注册为 beanFactory 处理器。
				invokeBeanFactoryPostProcessors(beanFactory);

				//注册能拦截 bean 创建的 bean 处理器，此处只是注册功能，真正调用的是getBean
				registerBeanPostProcessors(beanFactory);

				//为上下文初始化message源，即不同语言的消息体，国际化处理
				initMessageSource();

				//为此上下文初始化事件多播器
				initApplicationEventMulticaster();

				//留给子类来初始化其他bean
				onRefresh();

				//在所有注册的bean中查找listener bean，注册到消息广播器中
				registerListeners();

				// 初始化剩下的单实例（非懒加载），多例是在getBean时才初始化
				finishBeanFactoryInitialization(beanFactory);

				//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) {
				if (logger.isWarnEnabled()) {
					logger.warn("Exception encountered during context initialization - " +
							"cancelling refresh attempt: " + ex);
				}
				//销毁已经创建的单例以避免悬空资源
				destroyBeans();
				// Reset 'active' flag.
				//重置active标志
				cancelRefresh(ex);
				throw ex;
			}
			finally {
				//重置 Spring 核心中的常见自省缓存，因为我们可能不再需要单例 bean 的元数据
				resetCommonCaches();
			}
		}
	}

• 步骤：

1. prepareRefresh()
   
   作用：
   

2. obtainFreshBeanFactory()
   
   
   createBeanFactory----创建bean工厂
   
   进入loadBeanDefinition
   

走完loadBeanDefinitons后，beanFactory中的beandefinitionMap就不会为空了

然后一路再返回到AbstractApplicationContext

作用：

3. prepareBeanFactory(beanFactory)：beanFactory的准备工作，对各种属性进行填充

作用：

4. postProcessBeanFactory(BeanFactory的后置处理器，留给其子类做扩展用的)

postProcessBeanFactory方法是留给子类扩展的，可以在bean实例初始化之前注册后置处理器（类似prepareBeanFactory方法中的beanFactory.addBeanPostProcessor），空实现且没有子类覆盖。

5. invokeBeanFactoryPostProcessors（调用各种beanFactory处理器）

该方法执行BeanFactoryPostProcessor执行器

执行BeanFactoryPostProcessor 执行器

作用：

6. registerBeanPostProcessors
   注册bean处理器，这里只是注册功能，真正调用的是getBean方法

registerBeanPostProcessors方法的代码略多，就不在此贴出来了，简单的说，就是找出所有的bean的后置处理器(注意，是bean的后置处理器，不是beanFactory的后置处理器，bean后置处理器处理的是bean实例，beanfactory后置处理器处理的是bean的定义)，然后将这些bean的后置处理器分为三类：

registerBeanPostProcessors方法执行完毕后，beanFactory中已经保存了有序的bean后置处理器，在bean实例化之后，会依次使用这些后置处理器对bean实例来做对应的处理；

作用：

7. initMessageSource

为上下文初始化message源，即不同语言的消息体，国际化处理

8. initApplicationEventMulticaster

初始化事件监听多路广播器

作用：

9. onRefresh
   onRefresh是个空方法，留给子类自己实现的，在实例化bean之前做一些ApplicationContext相关的操作，以子类AbstractRefreshableWebApplicationContext为例，看看它的onRefresh方法

/**
 * Initialize the theme capability.
 */
@Override
protected void onRefresh() {
	this.themeSource = UiApplicationContextUtils.initThemeSource(this);
}

10. registerListeners

方法名为registerListeners，看名字像是将监听器注册在事件广播器中，但实际情况并非如此，只有一些特殊的监听器被注册了，那些在bean配置文件中实现了ApplicationListener接口的类还没有实例化，所以此处只是将其name保存在广播器中，将这些监听器注册在广播器的操作是在bean的后置处理器中完成的，那时候bean已经实例化完成了，我们看代码

作用：

11. finishBeanFactoryInitialization

初始化剩下的单实例（非懒加载的），多例在getBean时才初始化

• preInstantiateSingletons方法这个方法里就解决了循环依赖的问题

	@Override
	public void preInstantiateSingletons() throws BeansException {
		if (this.logger.isDebugEnabled()) {
			this.logger.debug("Pre-instantiating singletons in " + this);
		}
		// Iterate over a copy to allow for init methods which in turn register new bean definitions.
		// While this may not be part of the regular factory bootstrap, it does otherwise work fine.
		// 1.创建beanDefinitionNames的副本beanNames用于后续的遍历，以允许init等方法注册新的bean定义
		List<String> beanNames = new ArrayList<String>(this.beanDefinitionNames);
		// Trigger initialization of all non-lazy singleton beans...
		// 2.遍历beanNames，触发所有非懒加载单例bean的初始化
		for (String beanName : beanNames) {
			// 3.获取beanName对应的MergedBeanDefinition
			RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);
			// 4.bd对应的Bean实例：不是抽象类 && 是单例 && 不是懒加载
			if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {
				// 5.判断beanName对应的bean是否为FactoryBean
				if (isFactoryBean(beanName)) {
					// 5.1 通过beanName获取FactoryBean实例
					// 通过getBean(&beanName)拿到的是FactoryBean本身；通过getBean(beanName)拿到的是FactoryBean创建的Bean实例
					final FactoryBean<?> factory = (FactoryBean<?>) getBean(FACTORY_BEAN_PREFIX + beanName);
					// 5.2 判断这个FactoryBean是否希望急切的初始化
					boolean isEagerInit;
					if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
						isEagerInit = AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
							@Override
							public Boolean run() {
								return ((SmartFactoryBean<?>) factory).isEagerInit();
							}
						}, getAccessControlContext());
					} else {
						isEagerInit = (factory instanceof SmartFactoryBean &&
								((SmartFactoryBean<?>) factory).isEagerInit());
					}
					if (isEagerInit) {
						// 5.3 如果希望急切的初始化，则通过beanName获取bean实例
						getBean(beanName);
					}
				} else {
					// 6.如果beanName对应的bean不是FactoryBean，只是普通Bean，通过beanName获取bean实例
					getBean(beanName);
				}
			}
		}
		// Trigger post-initialization callback for all applicable beans...
		// 7.遍历beanNames，触发所有SmartInitializingSingleton的后初始化回调
		for (String beanName : beanNames) {
			// 7.1 拿到beanName对应的bean实例
			Object singletonInstance = getSingleton(beanName);
			// 7.2 判断singletonInstance是否实现了SmartInitializingSingleton接口
			if (singletonInstance instanceof SmartInitializingSingleton) {
				final SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance;
				// 7.3 触发SmartInitializingSingleton实现类的afterSingletonsInstantiated方法
				if (System.getSecurityManager() != null) {
					AccessController.doPrivileged(new PrivilegedAction<Object>() {
						@Override
						public Object run() {
							smartSingleton.afterSingletonsInstantiated();
							return null;
						}
					}, getAccessControlContext());
				} else {
					smartSingleton.afterSingletonsInstantiated();
				}

这里接下来的调用链条是：

getBean() -> doGetBean() -> createBean() -> doCreateBean() -> populateBean()//填充属性 -> initializeBean()//初始化(这里涉及到代理的创建)

initializeBean方法中会执行applyBeanPostProcessorsAfterInitialization方法

applyBeanPostProcessorsAfterInitialization具体的代码如下：

@Override
public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName)
      throws BeansException {

   Object result = existingBean;
   for (BeanPostProcessor processor : getBeanPostProcessors()) {
      Object current = processor.postProcessAfterInitialization(result, beanName);
      if (current == null) {
         return result;
      }
      result = current;
   }
   return result;
}

逻辑比较简单，就是遍历所有实现了BeanPostProcessor接口的类，其中AnnotationAwareAspectJAutoProxyCreator(由EnableAspectJAutoProxy导入的)就是会实现AOP动态代理，然后返回代理对象。所以如果没有导入@EnableAspectJAutoProxy,自然不会创建代理. 这里也可以看出applicationContext构造的过程,就会创建好代理.而且在创建代理的过程中,如果涉及到循环依赖还是提前创建代理并放入earlyProxyReferences集合，用于表示进行了提前的动态代理.这里可以参考这篇文章.注意,多实例对象并不会提前创建,当两个多实例对象循环引用且设计代理的创建时,就会报错

附表:SpringBoot常用的BeanPostProcessor清单

protected <T> T doGetBean(
			final String name, final Class<T> requiredType, final Object[] args, boolean typeCheckOnly)
			throws BeansException {
		// 1.解析beanName，主要是解析别名、去掉FactoryBean的前缀“&”
		final String beanName = transformedBeanName(name);
		Object bean;
		// Eagerly check singleton cache for manually registered singletons.
		// 2.尝试从缓存中获取beanName对应的实例
		Object sharedInstance = getSingleton(beanName);
		if (sharedInstance != null && args == null) {
			// 3.如果beanName的实例存在于缓存中,
			if (logger.isDebugEnabled()) {
				if (isSingletonCurrentlyInCreation(beanName)) {
					logger.debug("Returning eagerly cached instance of singleton bean '" + beanName +
							"' that is not fully initialized yet - a consequence of a circular reference");
				} else {
					logger.debug("Returning cached instance of singleton bean '" + beanName + "'");
				}
			}
			// 3.1 返回beanName对应的实例对象（主要用于FactoryBean的特殊处理，普通Bean会直接返回sharedInstance本身）
			bean = getObjectForBeanInstance(sharedInstance, name, beanName, null);
		} else {
			// Fail if we're already creating this bean instance:
			// We're assumably within a circular reference.
			// 4.scope为prototype的循环依赖校验：如果beanName已经正在创建Bean实例中，而此时我们又要再一次创建beanName的实例，则代表出现了循环依赖，需要抛出异常。
			// 例子：如果存在A中有B的属性，B中有A的属性，那么当依赖注入的时候，就会产生当A还未创建完的时候因为对于B的创建再次返回创建A，造成循环依赖
			if (isPrototypeCurrentlyInCreation(beanName)) {
				throw new BeanCurrentlyInCreationException(beanName);
			}
			// Check if bean definition exists in this factory.
			// 5.获取parentBeanFactory
			BeanFactory parentBeanFactory = getParentBeanFactory();
			// 5.1 如果parentBeanFactory存在，并且beanName在当前BeanFactory不存在Bean定义，则尝试从parentBeanFactory中获取bean实例
			if (parentBeanFactory != null && !containsBeanDefinition(beanName)) {
				// Not found -> check parent.
				// 5.2 将别名解析成真正的beanName
				String nameToLookup = originalBeanName(name);
				// 5.3 尝试在parentBeanFactory中获取bean对象实例
				if (args != null) {
					// Delegation to parent with explicit args.
					return (T) parentBeanFactory.getBean(nameToLookup, args);
				} else {
					// No args -> delegate to standard getBean method.
					return parentBeanFactory.getBean(nameToLookup, requiredType);
				}
			}
			if (!typeCheckOnly) {
				// 6.如果不是仅仅做类型检测，而是创建bean实例，这里要将beanName放到alreadyCreated缓存
				markBeanAsCreated(beanName);
			}
			try {
				// 7.根据beanName重新获取MergedBeanDefinition（步骤6将MergedBeanDefinition删除了，这边获取一个新的）
				final RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName);
				// 7.1 检查MergedBeanDefinition
				checkMergedBeanDefinition(mbd, beanName, args);
				// Guarantee initialization of beans that the current bean depends on.
				// 8.拿到当前bean依赖的bean名称集合，在实例化自己之前，需要先实例化自己依赖的bean
				String[] dependsOn = mbd.getDependsOn();
				if (dependsOn != null) {
					// 8.1 遍历当前bean依赖的bean名称集合
					for (String dep : dependsOn) {
						// 8.2 检查dep是否依赖于beanName，即检查是否存在循环依赖
						if (isDependent(beanName, dep)) {
							// 8.3 如果是循环依赖则抛异常
							throw new BeanCreationException(mbd.getResourceDescription(), beanName,
									"Circular depends-on relationship between '" + beanName + "' and '" + dep + "'");
						}
						// 8.4 将dep和beanName的依赖关系注册到缓存中
						registerDependentBean(dep, beanName);
						// 8.5 获取dep对应的bean实例，如果dep还没有创建bean实例，则创建dep的bean实例
						getBean(dep);
					}
				}
				// Create bean instance.
				// 9.针对不同的scope进行bean的创建
				if (mbd.isSingleton()) {
					// 9.1 scope为singleton的bean创建（新建了一个ObjectFactory，并且重写了getObject方法）
					sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() {
						@Override
						public Object getObject() throws BeansException {    //
							try {
								// 9.1.1 创建Bean实例
								return createBean(beanName, mbd, args);
							} catch (BeansException ex) {
								// Explicitly remove instance from singleton cache: It might have been put there
								// eagerly by the creation process, to allow for circular reference resolution.
								// Also remove any beans that received a temporary reference to the bean.
								destroySingleton(beanName);
								throw ex;
							}
						}
					});
					// 9.1.2 返回beanName对应的实例对象
					bean = getObjectForBeanInstance(sharedInstance, name, beanName, mbd);
				} else if (mbd.isPrototype()) {
					// 9.2 scope为prototype的bean创建
					// It's a prototype -> create a new instance.
					Object prototypeInstance = null;
					try {
						// 9.2.1 创建实例前的操作（将beanName保存到prototypesCurrentlyInCreation缓存中）
						beforePrototypeCreation(beanName);
						// 9.2.2 创建Bean实例
						prototypeInstance = createBean(beanName, mbd, args);
					} finally {
						// 9.2.3 创建实例后的操作（将创建完的beanName从prototypesCurrentlyInCreation缓存中移除）
						afterPrototypeCreation(beanName);
					}
					// 9.2.4 返回beanName对应的实例对象
					bean = getObjectForBeanInstance(prototypeInstance, name, beanName, mbd);
				} else {
					// 9.3 其他scope的bean创建，可能是request之类的
					// 9.3.1 根据scopeName，从缓存拿到scope实例
					String scopeName = mbd.getScope();
					final Scope scope = this.scopes.get(scopeName);
					if (scope == null) {
						throw new IllegalStateException("No Scope registered for scope name '" + scopeName + "'");
					}
					try {
						// 9.3.2 其他scope的bean创建（新建了一个ObjectFactory，并且重写了getObject方法）
						Object scopedInstance = scope.get(beanName, new ObjectFactory<Object>() {
							@Override
							public Object getObject() throws BeansException {
								// 9.3.3 创建实例前的操作（将beanName保存到prototypesCurrentlyInCreation缓存中）
								beforePrototypeCreation(beanName);
								try {
									// 9.3.4 创建bean实例
									return createBean(beanName, mbd, args);
								} finally {
									// 9.3.5 创建实例后的操作（将创建完的beanName从prototypesCurrentlyInCreation缓存中移除）
									afterPrototypeCreation(beanName);
								}
							}
						});
						// 9.3.6 返回beanName对应的实例对象
						bean = getObjectForBeanInstance(scopedInstance, name, beanName, mbd);
					} catch (IllegalStateException ex) {
						throw new BeanCreationException(beanName,
								"Scope '" + scopeName + "' is not active for the current thread; consider " +
										"defining a scoped proxy for this bean if you intend to refer to it from a singleton",
								ex);
					}
				}
			} catch (BeansException ex) {
				// 如果创建bean实例过程中出现异常，则将beanName从alreadyCreated缓存中移除
				cleanupAfterBeanCreationFailure(beanName);
				throw ex;
			}
		}
		// Check if required type matches the type of the actual bean instance.
		// 10.检查所需类型是否与实际的bean对象的类型匹配
		if (requiredType != null && bean != null && !requiredType.isInstance(bean)) {
			try {
				// 10.1 类型不对，则尝试转换bean类型
				return getTypeConverter().convertIfNecessary(bean, requiredType);
			} catch (TypeMismatchException ex) {
				if (logger.isDebugEnabled()) {
					logger.debug("Failed to convert bean '" + name + "' to required type '" +
							ClassUtils.getQualifiedName(requiredType) + "'", ex);
				}
				throw new BeanNotOfRequiredTypeException(name, requiredType, bean.getClass());
			}
		}
		// 11.返回创建出来的bean实例对象
		return (T) bean;
	}

作用：

12. finishRefresh

最后一个方法是finishRefresh，这是在bean的实例化、初始化等完成后的一些操作

protected void finishRefresh() {
		// Clear context-level resource caches (such as ASM metadata from scanning).
		// 清除上下文级别的资源缓存（如扫描的ASM元数据）
		// 清空在资源加载器中所有的资源缓存
		clearResourceCaches();

		// Initialize lifecycle processor for this context.
		// 为这个上下文初始化生命周期处理器
		// 初始化LifecycleProcessor，如果上下文中找到LifecycleProcessor的LifecycleProcessor bean对象，则使用DefaultLifecycleProcessor
		initLifecycleProcessor();

		// Propagate refresh to lifecycle processor first.
		// 首先将刷新传播到生命周期处理器，上下文刷新的通知，例如自启动的组件
		getLifecycleProcessor().onRefresh();

		// Publish the final event.
		// 发布最终事件
		// 新建ContextRefreshEvent事件对象，将其发布到所有监听器
		publishEvent(new ContextRefreshedEvent(this));

		// Participate in LiveBeansView MBean, if active.
		// 参与LiveBeansView MBean,如果是活动的。LiveBeansView ：Spring用于支持JMX服务的类
		// 注册当前上下文LiveBeansView，以支持JMX服务
		LiveBeansView.registerApplicationContext(this);
	}

作用:

13. resetCommonCaches()

在spring的核心中重置常见的内省缓存，因为我们可能不再需要singleton bean的元数据了

四、总结