1 minute read

  1. Issue
    • When I use both Actuator and Swagger in a project, I met below error message
    • ERROR org.springframework.boot.SpringApplication: Application run failed org.springframework.context.ApplicationContextException: Failed to start bean ‘documentationPluginsBootstrapper’ - Environment
    • Spring boot: 2.7.17
    • Spring Actuator: Same version with Spring boot
    • Spring fox swagger: 3.0.0
      • io.springfox:springfox-swagger2:3.0.0
      • io.springfox:springfox-swagger-ui:3.0.0
      • io.springfox:springfox-boot-starter:3.0.0
  2. Reason
    • Swagger and Actuator, they two are access endpoint in spring boot. So they have conflict of dependency each other.
    • Springfox swagger assume that Spring MVC use to Ant-based path matcher. But Upper Spring MVC 2.6.x is changed from Ant-based path matcher to PathPattern-based matcher.
    • Both two make this error
  3. Solution
    • Put below option under application.yml 
      spring:
  mvc:
 pathmatch:
   matching-strategy: ant_path_matcher
    • And then, Regist BeanPostProcessor bean for SpringfoxHandler like below example 
      @Configuration
public class Config {
@Bean
public static BeanPostProcessor springfoxHandlerProviderBeanPostProcessor() {
return new BeanPostProcessor() {

     @Override
     public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
         if (bean instanceof WebMvcRequestHandlerProvider || bean instanceof WebFluxRequestHandlerProvider) {
             customizeSpringfoxHandlerMappings(getHandlerMappings(bean));
         }
         return bean;
     }

     private <T extends RequestMappingInfoHandlerMapping> void customizeSpringfoxHandlerMappings(List<T> mappings) {
         List<T> copy = mappings.stream()
                 .filter(mapping -> mapping.getPatternParser() == null)
                 .collect(Collectors.toList());
         mappings.clear();
         mappings.addAll(copy);
     }

     @SuppressWarnings("unchecked")
     private List<RequestMappingInfoHandlerMapping> getHandlerMappings(Object bean) {
         try {
             Field field = ReflectionUtils.findField(bean.getClass(), "handlerMappings");
             field.setAccessible(true);
             return (List<RequestMappingInfoHandlerMapping>) field.get(bean);
         } catch (IllegalArgumentException | IllegalAccessException e) {
             throw new IllegalStateException(e);
         }
     }
 };
 }
  4. Reference
    • https://dkswnkk.tistory.com/672

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