Spring 5.x source Tour thirty Detailed fifteen initializeBean a getBean

initializeBean

Speaking in front populateBean, to the properties and methods of implantation bean, after completion, it is necessary to initialize call, in fact, deal with various processor interface.

	protected Object initializeBean(final String beanName, final Object bean, @Nullable RootBeanDefinition mbd) {
		if (System.getSecurityManager() != null) {
			AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
				invokeAwareMethods(beanName, bean);
				return null;
			}, getAccessControlContext());
		}
		else {//Aware接口处理器
			invokeAwareMethods(beanName, bean);
		}

		Object wrappedBean = bean;
		if (mbd == null || !mbd.isSynthetic()) {//初始化前
			wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
		}

		try {//初始化
			invokeInitMethods(beanName, wrappedBean, mbd);
		}
		catch (Throwable ex) {
			throw new BeanCreationException(
					(mbd != null ? mbd.getResourceDescription() : null),
					beanName, "Invocation of init method failed", ex);
		}
		if (mbd == null || !mbd.isSynthetic()) {//初始化后
			wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
		}

		return wrappedBean;
	}

invokeAwareMethods trigger prompt method

Processing BeanNameAware, BeanClassLoaderAware, BeanFactoryAwareinterface method, here BeanFactoryAware interface to note that if the previous configuration class has a CGLIBdynamic proxy, then this method will repeat it here, that is setBeanFactorycalled repeatedly twice, once in front of the EnhancedConfigurationinterface methods.

private void invokeAwareMethods(final String beanName, final Object bean) {
		if (bean instanceof Aware) {
			if (bean instanceof BeanNameAware) {//设置bean名字
				((BeanNameAware) bean).setBeanName(beanName);
			}
			if (bean instanceof BeanClassLoaderAware) {
				ClassLoader bcl = getBeanClassLoader();
				if (bcl != null) {//设置类加载器
					((BeanClassLoaderAware) bean).setBeanClassLoader(bcl);
				}
			}
			if (bean instanceof BeanFactoryAware) {//设置BeanFactory
				((BeanFactoryAware) bean).setBeanFactory(AbstractAutowireCapableBeanFactory.this);
			}
		}
	}

applyBeanPostProcessorsBeforeInitialization initialization process before

All BeanPostProcessorprocessing is returned if there is nulla direct return, or put objects treated replace the original, returns the latest object.

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

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

ApplicationContextAwareProcessor的postProcessBeforeInitialization

If you find that beanthere are a bunch of interfaces that implement any one, it would execute invokeAwareInterfacesthe method.

@Override
	@Nullable
	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
		if (!(bean instanceof EnvironmentAware || bean instanceof EmbeddedValueResolverAware ||
				bean instanceof ResourceLoaderAware || bean instanceof ApplicationEventPublisherAware ||
				bean instanceof MessageSourceAware || bean instanceof ApplicationContextAware)){
			return bean;
		}

		AccessControlContext acc = null;

		if (System.getSecurityManager() != null) {
			acc = this.applicationContext.getBeanFactory().getAccessControlContext();
		}

		if (acc != null) {
			AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
				invokeAwareInterfaces(bean);
				return null;
			}, acc);
		}
		else {
			invokeAwareInterfaces(bean);
		}

		return bean;
	}

invokeAwareInterfaces

In fact, set some value, easy to get outside and do some extensions.

private void invokeAwareInterfaces(Object bean) {
		if (bean instanceof EnvironmentAware) {
			((EnvironmentAware) bean).setEnvironment(this.applicationContext.getEnvironment());
		}
		if (bean instanceof EmbeddedValueResolverAware) {
			((EmbeddedValueResolverAware) bean).setEmbeddedValueResolver(this.embeddedValueResolver);
		}
		if (bean instanceof ResourceLoaderAware) {
			((ResourceLoaderAware) bean).setResourceLoader(this.applicationContext);
		}
		if (bean instanceof ApplicationEventPublisherAware) {
			((ApplicationEventPublisherAware) bean).setApplicationEventPublisher(this.applicationContext);
		}
		if (bean instanceof MessageSourceAware) {
			((MessageSourceAware) bean).setMessageSource(this.applicationContext);
		}
		if (bean instanceof ApplicationContextAware) {
			((ApplicationContextAware) bean).setApplicationContext(this.applicationContext);
		}
	}

ConfigurationClassPostProcessor inner class of postProcessBeforeInitialization ImportAwareBeanPostProcessor

If you are ImportAwarethe type, it will set beanthe annotation information.

@Override
		public Object postProcessBeforeInitialization(Object bean, String beanName) {
			if (bean instanceof ImportAware) {
				ImportRegistry ir = this.beanFactory.getBean(IMPORT_REGISTRY_BEAN_NAME, ImportRegistry.class);
				AnnotationMetadata importingClass = ir.getImportingClassFor(ClassUtils.getUserClass(bean).getName());
				if (importingClass != null) {
					((ImportAware) bean).setImportMetadata(importingClass);
				}
			}
			return bean;
		}

InitDestroyAnnotationBeanPostProcessor的postProcessBeforeInitialization

Here is our previous registration lifecycle metadata, this time to be called.

@Override
	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
		LifecycleMetadata metadata = findLifecycleMetadata(bean.getClass());
		try {
			metadata.invokeInitMethods(bean, beanName);
		}
		catch (InvocationTargetException ex) {
			throw new BeanCreationException(beanName, "Invocation of init method failed", ex.getTargetException());
		}
		catch (Throwable ex) {
			throw new BeanCreationException(beanName, "Failed to invoke init method", ex);
		}
		return bean;
	}

LifecycleMetadata 的invokeInitMethods

Recalling the Registered front set of initialization method checkedInitMethodsof each method.

	public void invokeInitMethods(Object target, String beanName) throws Throwable {
			Collection<LifecycleElement> checkedInitMethods = this.checkedInitMethods;
			Collection<LifecycleElement> initMethodsToIterate =
					(checkedInitMethods != null ? checkedInitMethods : this.initMethods);
			if (!initMethodsToIterate.isEmpty()) {
				for (LifecycleElement element : initMethodsToIterate) {
					if (logger.isTraceEnabled()) {
						logger.trace("Invoking init method on bean '" + beanName + "': " + element.getMethod());
					}
					element.invoke(target);
				}
			}
		}

LifecycleElement的invoke

Is the reflection method call, the argument is null.

		public void invoke(Object target) throws Throwable {
			ReflectionUtils.makeAccessible(this.method);
			this.method.invoke(target, (Object[]) null);
		}

Well, here today, we hope to help study and understand, do not spray the Great God see, understand only their own learning, limited capacity, please excuse.