Spring 5 Reactive - WebExceptionHandler is not getting called

Question

I have tried all 3 solutions suggested in what is the right way to handle errors in spring-webflux, but WebExceptionHandler is not getting called. I am using Spring Boot 2.0.0.M7. Github repo here

@Configuration
class RoutesConfiguration {

  @Autowired
  private lateinit var testService: TestService

  @Autowired
  private lateinit var globalErrorHandler: GlobalErrorHandler

  @Bean
  fun routerFunction():

    RouterFunction<ServerResponse> = router {
    ("/test").nest {

      GET("/") {
        ServerResponse.ok().body(testService.test())
      }
    }
  }


} 


@Component
class GlobalErrorHandler() : WebExceptionHandler {

  companion object {
    private val log = LoggerFactory.getLogger(GlobalErrorHandler::class.java)
  }

  override fun handle(exchange: ServerWebExchange?, ex: Throwable?): Mono<Void> {

    log.info("inside handle")

    /* Handle different exceptions here */
    when(ex!!) {
      is ClientException -> exchange!!.response.statusCode = HttpStatus.BAD_REQUEST
      is Exception -> exchange!!.response.statusCode = HttpStatus.INTERNAL_SERVER_ERROR
    }

    return Mono.empty()
  }
}

UPDATE:

When I change Spring Boot version to 2.0.0.M2, the WebExceptionHandler is getting called. Do I need to do something for 2.0.0.M7?

SOLUTION:

As per Brian's suggestion, it worked as

@Bean
@Order(-2)
fun globalErrorHandler() = GlobalErrorHandler()

Answer 1

You can provide your own WebExceptionHandler, but you have to order it relatively to others, otherwise they might handle the error before yours get a chance to try.

• the DefaultErrorWebExceptionHandler provided by Spring Boot for error handling (see reference documentation) is ordered at -1
• the ResponseStatusExceptionHandler provided by Spring Framework is ordered at 0

So you can add @Order(-2) on your error handling component, to order it before the existing ones.