Spring--BeanPostProcessor无法使用AOP--原因/解决方案

以你之姓@ 2023-09-28 11:41 28阅读 0赞

原文网址：[Spring--BeanPostProcessor无法使用AOP--原因/解决方案\_IT利刃出鞘的博客-CSDN博客][Spring--BeanPostProcessor_AOP--_IT_-CSDN]

## 简介 ##

本文介绍BeanPostProcessor为什么无法使用AOP以及其解决方案。

## 原因 ##

**简述**

BeanPostProcessor以及依赖的bean很有可能无法使用AOP。

此时，会有类似这样的打印信息：trationDelegate$BeanPostProcessorChecker : Bean 'myBean' of type \[com.example.processor.MyBean\] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)

**源码位置**

这个是由BeanPostProcessorChecker类打印出来的，在源码中搜索它，发现此类是PostProcessorRegistrationDelegate的静态内部类。

@Override
    public Object postProcessAfterInitialization(Object bean, String beanName) {
        if (!(bean instanceof BeanPostProcessor) && !isInfrastructureBean(beanName) &&
                this.beanFactory.getBeanPostProcessorCount() < this.beanPostProcessorTargetCount) {
            if (logger.isInfoEnabled()) {
                logger.info("Bean '" + beanName + "' of type [" + bean.getClass().getName() +
                        "] is not eligible for getting processed by all BeanPostProcessors " +
                        "(for example: not eligible for auto-proxying)");
            }
        }
        return bean;
    }

**打印此日志的原因**

若注册到beanFactory的BeanPostProcessor的数量少于总的BeanPostProcessor的数量。即：有其他后置处理器还没准备好，这个bean（此处是myBean）就被实例化了。这个bean被实例化的原因一般是：BeanPostProcessor的实现类引用了这个bean，导致这个bean的实例化。

**官网文档**

[Spring官方文档][Spring]的原话：

BeanPostProcessor instances and AOP auto-proxying

Classes that implement the BeanPostProcessor interface are special and are treated differently by the container. All BeanPostProcessor instances and beans that they directly reference are instantiated on startup, as part of the special startup phase of the ApplicationContext. Next, all BeanPostProcessor instances are registered in a sorted fashion and applied to all further beans in the container. Because AOP auto-proxying is implemented as a BeanPostProcessor itself, neither BeanPostProcessor instances nor the beans they directly reference are eligible for auto-proxying and, thus, do not have aspects woven into them.

For any such bean, you should see an informational log message: Bean someBean is not eligible for getting processed by all BeanPostProcessor interfaces (for example: not eligible for auto-proxying).

翻译：

实现了BeanPostProcessor 接口的类是特殊的，它们会被容器不同地对待。所有的BeanPostProcessor 实例和它们直接引用的beans在启动时被实例化，它们作为ApplicationContext的特殊启动阶段的一部分。然后，所有的BeanPostProcessor 实例都被以一个排序方式注册而且被应用到下一步的beans中。**因为Spring的AOP自动代理是通过实现BeanPostProcessor接口来做的，所以BeanPostProcessor的实现类和它们直接引用的bean不满足AOP自动代理的条件，因此，它们无法被织入到AOP中**。

对于这些bean，你会看到一些INFO级别的信息：Bean someBean is not eligible for getting processed by all BeanPostProcessor interfaces (for example: not eligible for auto-proxying).

## 问题复现 ##

### 代码 ###

上边是文章的部分内容，为便于维护，全文已转移到此网址：[Spring-BeanPostProcessor无法使用AOP-原因/解决方案 - 自学精灵][Spring-BeanPostProcessor_AOP-_ -]

[Spring--BeanPostProcessor_AOP--_IT_-CSDN]: https://knife.blog.csdn.net/article/details/125396697
[Spring]: https://docs.spring.io/spring-framework/docs/current/reference/html/core.html#beans-factory-extension-bpp
[Spring-BeanPostProcessor_AOP-_ -]: https://learn.skyofit.com/archives/2020