Spring源码阅读（七）

/**
* Initialize the given bean instance, applying factory callbacks
* as well as init methods and bean post processors.
* 生成bean实例，并且回调诸如init methods，bean post processors方法
* <p>Called from {@link #createBean} for traditionally defined beans,
* and from {@link #initializeBean} for existing bean instances.
* @param beanName the bean name in the factory (for debugging purposes)
* @param bean the new bean instance we may need to initialize
* @param mbd the bean definition that the bean was created with
* (can also be {@code null}, if given an existing bean instance)
* @return the initialized bean instance (potentially wrapped)
* @see BeanNameAware
* @see BeanClassLoaderAware
* @see BeanFactoryAware
* @see #applyBeanPostProcessorsBeforeInitialization
* @see #invokeInitMethods
* @see #applyBeanPostProcessorsAfterInitialization
*/
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 {
// 执行BeanNameAware，BeanClassLoaderAware，BeanFactoryAware接口方法
invokeAwareMethods(beanName, bean);
}

Object wrappedBean = bean;
if (mbd == null || !mbd.isSynthetic()) {
// 执行BeanPostProcessor的postProcessBeforeInitialization方法，包括@PostConstruct注解方法
wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
}

try {
// 执行InitializingBean的afterPropertiesSet方法，包括init-method方法
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()) {
// 执行BeanPostProcessor的postProcessAfterInitialization方法
wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
}

return wrappedBean;
}