Spring 找到没有注入其他bean的bean

Question

I want to find all beans that are not injected into other beans, thus I can remove them to make spring start up faster. Any ideas? Thanks in advance.

Answer 1

From ConfigurableBeanFactory#getDependentBeans Javadoc , I see that there's a method we can invoke to get an array of beans that depends on the bean name we provide. Tracing backwards to how we can get the bean factory. You could probably do the following if you can get a hold of the GenericApplicationContext :

1. Get the bean factory from the context.
2. Iterate through the bean definition names in the bean factory.
3. Call ConfigurableBeanFactory::getDependentBeans to see if anything depends on it.

@Component
public class Example {
   @EventListener
   public void contextRefreshed(ContextRefreshedEvent event) {
      // Could also just autowire the context directly 
      GenericApplicationContext context = (GenericApplicationContext) event.getApplicationContext();
      ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();

      String[] beanNames = beanFactory.getBeanDefinitionNames();
      for(String beanName : beanNames) {
         String[] dependentBeanNames = beanFactory.getDependentBeans(beanName);
        
         if (dependentBeanNames.length <= 0) {
            // bean with nothing depending on it
         }
      }
   }
}

Edit: This solution isn't perfect, but would probably be useful as a starting point. There are beans that could have nothing depend on it, but are used in the application. A good example would be your controllers (classes annotated with @Controller ). From what I tested out, it had 0 dependent beans but the request mapping methods it holds is clearly being executed and referenced somehow.