// 摘至 spring cloud alibaba console 模塊處理
@ControllerAdvice
public class ConsoleExceptionHandler {

  @ExceptionHandler(AccessException.class)
  private ResponseEntity<String> handleAccessException(AccessException e) {
    return ResponseEntity.status(HttpStatus.FORBIDDEN).body(e.getErrMsg());
  }
}

public class ExceptionHandlingWebHandler extends WebHandlerDecorator {
  @Override
  public Mono<Void> handle(ServerWebExchange exchange) {
    Mono<Void> completion;
    try {
      completion = super.handle(exchange);
    }
    catch (Throwable ex) {
      completion = Mono.error(ex);
    }

   // 獲取全局的 WebExceptionHandler 執(zhí)行
    for (WebExceptionHandler handler : this.exceptionHandlers) {
      completion = completion.onErrorResume(ex -> handler.handle(exchange, ex));
    }
    return completion;
  }
}

public class DefaultErrorWebExceptionHandler {

  @Override
  protected RouterFunction<ServerResponse> getRoutingFunction(ErrorAttributes errorAttributes) {
   // 根據(jù)客戶端 `accpet` 請(qǐng)求頭決定返回什么資源，如上瀏覽器返回的是 頁面
    return route(acceptsTextHtml(), this::renderErrorView).andRoute(all(), this::renderErrorResponse);
  }
}

// 模擬指定 `accpet` 情況
curl --location --request GET 'http://localhost:9999/adminx/xx' \ 18:09:23
   --header 'Accept: application/json'
{"timestamp":"2020-05-24 18:09:24","path":"/adminx/xx","status":404,"error":"Not Found","message":null,"requestId":"083c48e3-2"}⏎

/**
 * @author lengleng
 * @date 2020/5/23
 * <p>
 * 網(wǎng)關(guān)異常通用處理器，只作用在webflux 環(huán)境下 , 優(yōu)先級(jí)低于 {@link ResponseStatusExceptionHandler} 執(zhí)行
 */
@Slf4j
@Order(-1)
@RequiredArgsConstructor
public class GlobalExceptionConfiguration implements ErrorWebExceptionHandler {
  private final ObjectMapper objectMapper;

  @Override
  public Mono<Void> handle(ServerWebExchange exchange, Throwable ex) {
    ServerHttpResponse response = exchange.getResponse();

    if (response.isCommitted()) {
      return Mono.error(ex);
    }

    // header set
    response.getHeaders().setContentType(MediaType.APPLICATION_JSON);
    if (ex instanceof ResponseStatusException) {
      response.setStatusCode(((ResponseStatusException) ex).getStatus());
    }

    return response
        .writeWith(Mono.fromSupplier(() -> {
          DataBufferFactory bufferFactory = response.bufferFactory();
          try {
            return bufferFactory.wrap(objectMapper.writeValueAsBytes(R.failed(ex.getMessage())));
          } catch (JsonProcessingException e) {
            log.warn("Error writing response", ex);
            return bufferFactory.wrap(new byte[0]);
          }
        }));
  }
}