@Override
protected Object createBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
        throws BeanCreationException {
    //...
    try {
        // Give BeanPostProcessors a chance to return a proxy instead of the target bean instance.
        Object bean = resolveBeforeInstantiation(beanName, mbdToUse);
        if (bean != null) {
            return bean;
        }
    }
    try {
        Object beanInstance = doCreateBean(beanName, mbdToUse, args);
        return beanInstance;
    }
    //...
}

@Nullable
protected Object resolveBeforeInstantiation(String beanName, RootBeanDefinition mbd) {
    Object bean = null;
    if (!Boolean.FALSE.equals(mbd.beforeInstantiationResolved)) {
        // Make sure bean class is actually resolved at this point.
        if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
            Class<?> targetType = determineTargetType(beanName, mbd);
            if (targetType != null) {
                bean = applyBeanPostProcessorsBeforeInstantiation(targetType, beanName);
                if (bean != null) {
                    bean = applyBeanPostProcessorsAfterInitialization(bean, beanName);
                }
            }
        }
        mbd.beforeInstantiationResolved = (bean != null);
    }
    return bean;
}

@Nullable
protected Object applyBeanPostProcessorsBeforeInstantiation(Class<?> beanClass, String beanName) {
    for (InstantiationAwareBeanPostProcessor bp : getBeanPostProcessorCache().instantiationAware) {
        Object result = bp.postProcessBeforeInstantiation(beanClass, beanName);
        if (result != null) {
            return result;
        }
    }
    return null;
}

@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;
}

public class BookService {
    public void hello() {
        System.out.println("hello javaboy");
    }
}

public class MyInstantiationAwareBeanPostProcessor implements InstantiationAwareBeanPostProcessor {
    @Override
    public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
        if (beanClass == BookService.class) {
            Enhancer enhancer = new Enhancer();
            enhancer.setSuperclass(beanClass);
            enhancer.setCallback((MethodInterceptor) (obj, method, args, proxy) -> {
                String name = method.getName();
                System.out.println(name + " 方法開始執(zhí)行了...");
                Object invoke = proxy.invokeSuper(obj, args);
                System.out.println(name + " 方法執(zhí)行結(jié)束了...");
                return invoke;
            });
            BookService bookService = (BookService) enhancer.create();
            return bookService;
        }
        return InstantiationAwareBeanPostProcessor.super.postProcessBeforeInstantiation(beanClass, beanName);
    }
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("bean.getClass() ========= " + bean.getClass());
        return InstantiationAwareBeanPostProcessor.super.postProcessAfterInitialization(bean, beanName);
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean class="org.javaboy.bean.aop2.BookService" id="bookService"/>
    <bean class="org.javaboy.bean.aop2.MyInstantiationAwareBeanPostProcessor"
          id="myInstantiationAwareBeanPostProcessor"/>
</beans>

ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("aop2.xml");
BookService bs = ctx.getBean(BookService.class);
System.out.println("bs.getClass() = " + bs.getClass());
bs.hello();

@Component
@Aspect
@EnableAspectJAutoProxy
public class LogAspect {
    //...
}

@Override
public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) {
    Object cacheKey = getCacheKey(beanClass, beanName);
    if (!StringUtils.hasLength(beanName) || !this.targetSourcedBeans.contains(beanName)) {
        if (isInfrastructureClass(beanClass) || shouldSkip(beanClass, beanName)) {
            this.advisedBeans.put(cacheKey, Boolean.FALSE);
            return null;
        }
    }
    //...
}

@Override
protected boolean isInfrastructureClass(Class<?> beanClass) {
    return (super.isInfrastructureClass(beanClass) ||
            (this.aspectJAdvisorFactory != null && this.aspectJAdvisorFactory.isAspect(beanClass)));
}

protected boolean isInfrastructureClass(Class<?> beanClass) {
    boolean retVal = Advice.class.isAssignableFrom(beanClass) ||
            Pointcut.class.isAssignableFrom(beanClass) ||
            Advisor.class.isAssignableFrom(beanClass) ||
            AopInfrastructureBean.class.isAssignableFrom(beanClass);
    return retVal;
}

@Override
public boolean isAspect(Class<?> clazz) {
    return (hasAspectAnnotation(clazz) && !compiledByAjc(clazz));
}
private boolean hasAspectAnnotation(Class<?> clazz) {
    return (AnnotationUtils.findAnnotation(clazz, Aspect.class) != null);
}