java - Spring 启动 : BeanFactoryPostProcessor's postProcessBeanFactory not getting called

Question

Spring constructor injection of SLF4J logger - how to get injection target class?

我想在 Spring boot 中实现类似的功能。

我尝试了针对这个问题给出的解决方案，但似乎 BeanFactoryPostProcessor 的 postProcessBeanFactory 方法从未在我的 Spring-Boot 应用程序中被调用

下面是方法的实现:

@SuppressWarnings("unused")
public class LoggerBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        String [] beanClasses = beanFactory.getBeanDefinitionNames();
        for(String beanName : beanClasses){
            Object beanObject = beanFactory.getBean(beanName);
            if(beanObject.getClass().isAnnotationPresent(Loggable.class)){
                try {
                    Field loggerField = beanObject.getClass().getDeclaredField("logger");
                    loggerField.setAccessible(true);
                    loggerField.set(beanObject, LoggerFactory.getLogger(beanObject.getClass()));
                }catch (NoSuchFieldException | IllegalAccessException e){
                    e.printStackTrace();
                }
            }
        }
    }

Answer 1

Spring 应该知道您已经添加了一个新的 BeanFactoryPostProcessor，因此您应该将其声明为一个 bean 到您的配置中。对于 xml 配置:

<bean class="your.package.LoggerBeanFactoryPostProcessor"  />

对于 JavaConfig:

@Bean
public static BeanFactoryPostProcessor loggerBeanFactoryPostProcessor() {
    return new LoggerBeanFactoryPostProcessor();
}

注意:一定要在您的 JavaConfig 中创建一个返回静态 BeanFactoryPostProcessor 的方法。没有它会很好地工作，直到你想使用其他一些与 spring 相关的功能。例如，使用属性 @Value 将不起作用。

来自documentation :

By marking this method as static, it can be invoked without causing instantiation of its declaring @Configuration class, thus avoiding the above-mentioned lifecycle conflicts. Note however that static @Bean methods will not be enhanced for scoping and AOP semantics as mentioned above. This works out in BFPP cases, as they are not typically referenced by other @Bean methods.