Spring源码-initializeBean

initializeBean

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

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

	try {
		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()) {
		wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
	}

	return wrappedBean;
}

1. initializeBean方法调用invokeAwareMethods为实现了BeanNameAware，BeanClassLoaderAware，BeanFactoryAware的接口注入相应的bean。

2. 调用BeanPostProcessor的postProcessBeforeInitialization。

3. 调用init方法

4. 调用BeanPostProcessor的postProcessAfterInitialization。

   private void invokeAwareMethods(String beanName, Object bean) {
    if (bean instanceof Aware) {
    	if (bean instanceof BeanNameAware) {
    		((BeanNameAware) bean).setBeanName(beanName);
    	}
    	if (bean instanceof BeanClassLoaderAware) {
    		ClassLoader bcl = getBeanClassLoader();
    		if (bcl != null) {
    			((BeanClassLoaderAware) bean).setBeanClassLoader(bcl);
    		}
    	}
    	if (bean instanceof BeanFactoryAware) {
    		((BeanFactoryAware) bean).setBeanFactory(AbstractAutowireCapableBeanFactory.this);
    	}
    }
   

   }

initializeBean方法调用invokeAwareMethods为实现了BeanNameAware，BeanClassLoaderAware，BeanFactoryAware的接口注入相应的属性。

@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;
}

调用BeanPostProcessor的postProcessBeforeInitialization。

protected void invokeInitMethods(String beanName, Object bean, @Nullable RootBeanDefinition mbd)
		throws Throwable {

	boolean isInitializingBean = (bean instanceof InitializingBean);
	if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) {
		if (logger.isTraceEnabled()) {
			logger.trace("Invoking afterPropertiesSet() on bean with name '" + beanName + "'");
		}
		if (System.getSecurityManager() != null) {
			try {
				AccessController.doPrivileged((PrivilegedExceptionAction<Object>) () -> {
					((InitializingBean) bean).afterPropertiesSet();
					return null;
				}, getAccessControlContext());
			}
			catch (PrivilegedActionException pae) {
				throw pae.getException();
			}
		}
		else {
			((InitializingBean) bean).afterPropertiesSet();
		}
	}

	if (mbd != null && bean.getClass() != NullBean.class) {
		String initMethodName = mbd.getInitMethodName();
		if (StringUtils.hasLength(initMethodName) &&
				!(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) &&
				!mbd.isExternallyManagedInitMethod(initMethodName)) {
			invokeCustomInitMethod(beanName, bean, mbd);
		}
	}
}

调用init方法，先调用InitializingBean的afterPropertiesSet方法，再调用自定义的init方法。

@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;
}

调用BeanPostProcessor 的postProcessAfterInitialization方法。