Spring Boot 全局控制器建议未加载到 Spring Context 中

在使用Spring Boot开发Web应用程序时，我们经常会遇到一个常见的问题：全局控制器未加载到Spring Context中。这意味着我们无法通过自动装配来访问这些控制器，导致应用程序无法正常运行。这篇文章将介绍这个问题的原因，并提供一种解决方案。

java
@ComponentScan(basePackages = "com.example.controllers")
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

java
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Component
public @interface GlobalController {
}

java
@GlobalController
@ControllerAdvice
public class GlobalExceptionHandler {
    // ...
}

java
@Component
public class GlobalControllerProcessor implements BeanDefinitionRegistryPostProcessor {
    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
        ClassPathScanningCandidateComponentProvider provider = new ClassPathScanningCandidateComponentProvider(false);
        provider.addIncludeFilter(new AnnotationTypeFilter(GlobalController.class));
        for (BeanDefinition beanDef : provider.findCandidateComponents("com.example.controllers")) {
            registry.registerBeanDefinition(beanDef.getBeanClassName(), beanDef);
        }
    }
    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        // do nothing
    }
}