【小家Spring】注意BeanPostProcessor启动时对依赖Bean的“误伤”陷阱（is not eligible for getting processed by all...）（下）

// 和上面唯一区别是 此处实现的是`PriorityOrdered`接口，上面就是普通的Ordered接口
@Slf4j
@Component
public class MyBeanPostProcessor implements BeanPostProcessor, PriorityOrdered{
  @Autowired
    private ApplicationContext applicationContext;
    ...
}

  private static final class BeanPostProcessorChecker implements BeanPostProcessor {
    private static final Log logger = LogFactory.getLog(BeanPostProcessorChecker.class);
    // 从if条件可以看出哪些是不需要检测的Bean
    // 1、BeanPostProcessor类型不检测
    // 2、ROLE_INFRASTRUCTURE这种类型的Bean不检测 （Spring自己的Bean）
    @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;
    }
    private boolean isInfrastructureBean(@Nullable String beanName) {
      if (beanName != null && this.beanFactory.containsBeanDefinition(beanName)) {
        BeanDefinition bd = this.beanFactory.getBeanDefinition(beanName);
        return (bd.getRole() == RootBeanDefinition.ROLE_INFRASTRUCTURE);
      }
      return false;
    }
  }

Bean 'XXX' of type [XXXX] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)

// 在对它（AsyncAnnotationBeanPostProcessor）进行实例化的时候（它是个BeanPostProcessor，所以会根据bean定义进行getBean()）
// 所以就必须先实例化它@Bean所在的类：
@Configuration
@Role(BeanDefinition.ROLE_INFRASTRUCTURE)
public class ProxyAsyncConfiguration extends AbstractAsyncConfiguration {
  @Bean(name = TaskManagementConfigUtils.ASYNC_ANNOTATION_PROCESSOR_BEAN_NAME)
  @Role(BeanDefinition.ROLE_INFRASTRUCTURE)
  public AsyncAnnotationBeanPostProcessor asyncAdvisor() { ... }
}
// 然后它的父类`AbstractAsyncConfiguration`里有个@Autowired方法：
@Configuration
public abstract class AbstractAsyncConfiguration implements ImportAware {
  @Autowired(required = false)
  void setConfigurers(Collection<AsyncConfigurer> configurers) { ... }
}
// 这个依赖注入就会去容器内找所有的`AsyncConfigurer`的实现，所以就把`AsyncConfig`给提前实例化了
// 所以打印了那么一句日志，不要感觉到惊奇。这也是为何spring这个checker里使用的日志级别是Info，而不是debug，更不是worn。
// 因为它Spring认为这个debug太轻了，但是warn又太重了，因为绝大部分情况下它都不影响程序的正常work~