第11節講到InstantiationAwareBeanPostProcessor在bean被Spring“注入”屬性之前將其帶走了，那沒被InstantiationAwareBeanPostProcessor帶走的bean，接下來面對的是什麼呢？
書接上文：回到AbstractAutowireCapableBeanFactory.doCreateBean(String beanName,RootBeanDefinition mbd,Object[] args)
方法：
protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final @Nullable Object[] args)
throws BeanCreationException {
// Instantiate the bean.
BeanWrapper instanceWrapper = createBeanInstance(beanName, mbd, args);
。。。
// Initialize the bean instance.
Object exposedObject = bean;
try {
//給至尊寶一個機會，否則注入beanDefinition的屬性
populateBean(beanName, mbd, instanceWrapper);
//初始化bean
exposedObject = initializeBean(beanName, exposedObject, mbd);
}
。。。
return exposedObject;
}
populateBean(beanName,mbd,instanceWrapper);
這一段代碼是InstantiationAwareBeanPostProcessor在執行完postProcessAfterInstantiation之後。再次執行InstantiationAwareBeanPostProcessor接口的postProcessProperties/postProcessPropertyValues兩個方法：
查看接口定義
/**
* Post-process the given property values before the factory applies them
* to the given bean, without any need for property descriptors.
* <p>Implementations should return {@code null} (the default) if they provide a custom
* {@link #postProcessPropertyValues} implementation, and {@code pvs} otherwise.
* In a future version of this interface (with {@link #postProcessPropertyValues} removed),
* the default implementation will return the given {@code pvs} as-is directly.
* @param pvs the property values that the factory is about to apply (never {@code null})
* @param bean the bean instance created, but whose properties have not yet been set
* @param beanName the name of the bean
* @return the actual property values to apply to the given bean (can be the passed-in
* PropertyValues instance), or {@code null} which proceeds with the existing properties
* but specifically continues with a call to {@link #postProcessPropertyValues}
* (requiring initialized {@code PropertyDescriptor}s for the current bean class)
* @throws org.springframework.beans.BeansException in case of errors
* @since 5.1
* @see #postProcessPropertyValues
*/
@Nullable
default PropertyValues postProcessProperties(PropertyValues pvs, Object bean, String beanName)
throws BeansException {
return null;
}
/**
* Post-process the given property values before the factory applies them
* to the given bean. Allows for checking whether all dependencies have been
* satisfied, for example based on a "Required" annotation on bean property setters.
* <p>Also allows for replacing the property values to apply, typically through
* creating a new MutablePropertyValues instance based on the original PropertyValues,
* adding or removing specific values.
* <p>The default implementation returns the given {@code pvs} as-is.
* @param pvs the property values that the factory is about to apply (never {@code null})
* @param pds the relevant property descriptors for the target bean (with ignored
* dependency types - which the factory handles specifically - already filtered out)
* @param bean the bean instance created, but whose properties have not yet been set
* @param beanName the name of the bean
* @return the actual property values to apply to the given bean (can be the passed-in
* PropertyValues instance), or {@code null} to skip property population
* @throws org.springframework.beans.BeansException in case of errors
* @see #postProcessProperties
* @see org.springframework.beans.MutablePropertyValues
* @deprecated as of 5.1, in favor of {@link #postProcessProperties(PropertyValues, Object, String)}
*/
@Deprecated
@Nullable
default PropertyValues postProcessPropertyValues(
PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeansException {
return pvs;
}
下面的postProcessPropertyValue已經廢棄，推薦使用postProcessProperties方法，在給定的BeanDefinition的屬性被設置到bean裏面之前，可以BeanDefinition中的PropertyValues,看簡單的示例：
獲取到userHolder對象，進行了屬性修改，descript修改成“至尊寶沒帶走我”
原始屬性是：
最終輸出結果
調用堆棧：
綜上所述：在配置的BeanDefinition的propertyValues被設置到bean實例中之前，我們有機會攔截屬性，並更改屬性。
具體方法就是實現InstantiationAwareBeanPostProcessor的postProcessProperties