春天无法返回带有异常详细信息的ResponseEntity

Question

我创建了一个Spring Restful Service和Spring MVC应用程序。

Restful Service :: Restful Service返回一个实体（如果它存在于数据库中）。如果不存在，则在ResponseEntity对象中返回自定义Exception信息。

它正在使用邮递员进行预期的测试。

@GetMapping(value = "/validate/{itemId}", produces = { MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE })
public ResponseEntity<MyItem> validateItem(@PathVariable Long itemId, @RequestHeader HttpHeaders httpHeaders) {

    MyItem myItem = myitemService.validateMyItem(itemId);
    ResponseEntity<MyItem> responseEntity = null;
    if (myItem == null) {
        throw new ItemNotFoundException("Item Not Found!!!!");
    }
    responseEntity = new ResponseEntity<MyItem>(myItem, headers, HttpStatus.OK);
    return responseEntity;
}

如果所请求的实体不存在，Restful Service将在下面返回。

@ExceptionHandler(ItemNotFoundException.class)
public ResponseEntity<ExceptionResponse> itemNotFEx(WebRequest webRequest, Exception exception) {
    System.out.println("In CREEH::ItemNFE");
    ExceptionResponse exceptionResponse = new ExceptionResponse("Item Not Found Ex!!!", new Date(), webRequest.getDescription(false));
    ResponseEntity<ExceptionResponse> responseEntity = new ResponseEntity<ExceptionResponse>(exceptionResponse, HttpStatus.NOT_FOUND);
    return responseEntity;
}

但是，当我使用RestTemplate从Spring MVC应用程序调用上述服务时，它将返回有效对象（如果存在）。

如果所请求的对象不存在，那么Restful服务将返回异常信息，但是该异常信息不会到达调用（spring MVC）应用程序。

Spring MVC应用程序使用Rest模板调用Restful Web Service

String url = "http://localhost:8080/ItemServices/items/validate/{itemId}";
ResponseEntity<Object> responseEntity = restTemplate.exchange(url, HttpMethod.GET, httpEntity, Object.class, uriParms);
int restCallStateCode = responseEntity.getStatusCodeValue();

Answer 1

这是预期的行为。当 http 状态为客户端错误或服务器错误时，Rest 模板抛出异常，当 http 状态不是错误状态时返回响应。

您必须提供实现以使用您的错误处理程序，将响应映射到响应实体并抛出异常。

使用 ResponseEntity 字段创建新的错误异常类。

public class ResponseEntityErrorException extends RuntimeException {
  private ResponseEntity<ErrorResponse> errorResponse;
  public ResponseEntityErrorException(ResponseEntity<ErrorResponse> errorResponse) {
      this.errorResponse = errorResponse;
  }
  public ResponseEntity<ErrorResponse> getErrorResponse() {
      return errorResponse;
  }
}

将错误响应映射回 ResponseEntity 的自定义错误处理程序。

public class ResponseEntityErrorHandler implements ResponseErrorHandler {

  private List<HttpMessageConverter<?>> messageConverters;

  @Override
  public boolean hasError(ClientHttpResponse response) throws IOException {
    return hasError(response.getStatusCode());
  }

  protected boolean hasError(HttpStatus statusCode) {
    return (statusCode.is4xxClientError() || statusCode.is5xxServerError());
  }

  @Override
  public void handleError(ClientHttpResponse response) throws IOException {
    HttpMessageConverterExtractor<ExceptionResponse> errorMessageExtractor =
      new HttpMessageConverterExtractor(ExceptionResponse.class, messageConverters);
    ExceptionResponse errorObject = errorMessageExtractor.extractData(response);
    throw new ResponseEntityErrorException(ResponseEntity.status(response.getRawStatusCode()).headers(response.getHeaders()).body(errorObject));
  }

  public void setMessageConverters(List<HttpMessageConverter<?>> messageConverters) {
    this.messageConverters = messageConverters;
  }
}

RestTemplate 配置 - 您必须将 RestTemplate 的 errorHandler 设置为 ResponseEntityErrorHandler。

@Configuration
public class RestTemplateConfiguration {
  @Bean
  public RestTemplate restTemplate() {
      RestTemplate restTemplate = new RestTemplate();
      ResponseEntityErrorHandler errorHandler = new ResponseEntityErrorHandler();
      errorHandler.setMessageConverters(restTemplate.getMessageConverters());
      restTemplate.setErrorHandler(errorHandler); 
      return restTemplate;
   }
}

调用方式

@Autowired restTemplate

String url = "http://localhost:8080/ItemServices/items/validate/{itemId}";
try {
    ResponseEntity<Object> responseEntity = restTemplate.exchange(url, HttpMethod.GET, httpEntity, Object.class, uriParms);
    int restCallStateCode = responseEntity.getStatusCodeValue();
} catch (ResponseEntityErrorException re) {
    ResponseEntity<ErrorResponse> errorResponse = re.getErrorResponse();
}