如何检索FeignClient生成的errorResponse?

我正在寻找一种方法来检索由异常引起的原始响应,该异常已通过FeignClient在称为RemoteService的微服务中引发。

在微服务“地图”中,我公开了一个API来通过id查找位置:

@RestController
@RequiredArgsConstructor
@RequestMapping("/api/location")
public class LocationRestController {

    private final LocationService locationService;

    @GetMapping(value = "/{id}", produces = MediaType.APPLICATION_JSON_VALUE)
    public @ResponseBody LocationDto findById(@PathVariable Long id) throws FunctionalException {
        return locationService.findByIdToDto(id);
    }

}

如果找到,API将返回LocationDto,否则,它将抛出由RestControllerAdvice处理的FunctionalException,以便返回ExceptionResponse:

@RestControllerAdvice
public class ExceptionRestController {

    @ResponseBody
    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
    @ExceptionHandler(value = { FunctionalException.class })
    public ExceptionResponse handleFunctionalException(FunctionalException exception) {
        return new ExceptionResponse(exception, Map.of("uniqueIdentifier", exception.getUniqueIdentifier()));
    }

    @ResponseBody
    @ExceptionHandler(Exception.class)
    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
    public ExceptionResponse handleAllUncaughtException(Exception exception) {
        return new ExceptionResponse(exception);
    }

}

异常响应是:

@Log4j2
@Data
public class ExceptionResponse {

    @JsonProperty
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    private final LocalDateTime timestamp;

    @JsonProperty
    private final String status;

    @JsonProperty
    private final String error;

    @JsonProperty
    private String uniqueIdentifier = "";

    @JsonProperty
    private final String message;

    @JsonProperty
    private final String stackTrace;
    
    public ExceptionResponse(Exception exception) {
        timestamp = LocalDateTime.now();
        status = String.valueOf(HttpStatus.INTERNAL_SERVER_ERROR.value());
        error = HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase();
        message = exception.getMessage();
        stackTrace = ExceptionUtils.getStackTrace(exception);
        log.error(stackTrace);
    }
    
    public ExceptionResponse(Exception exception, Map<String, String> fieldValue) {
        timestamp = LocalDateTime.now();
        status = fieldValue.getOrDefault("status", String.valueOf(HttpStatus.INTERNAL_SERVER_ERROR.value()));
        error = fieldValue.getOrDefault("error", HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase());
        uniqueIdentifier = fieldValue.getOrDefault("uniqueIdentifier", "");
        message = fieldValue.getOrDefault("message", exception.getMessage());
        stackTrace = ExceptionUtils.getStackTrace(exception);
        log.error(stackTrace);
    }

    @JsonCreator
    public ExceptionResponse(LocalDateTime timestamp, String status, String error, String uniqueIdentifier,
            String message, String stackTrace) {
        this.timestamp = timestamp;
        this.status = status;
        this.error = error;
        this.uniqueIdentifier = uniqueIdentifier;
        this.message = message;
        this.stackTrace = stackTrace;
    }

}

在微服务“超市”中,我不得不使用OpenFeign将微服务的API称为“地图”:

@FeignClient(name = "mapsClient", url = "http://localhost:9888", configuration = ClientConfiguration.class)
public interface MapsRemoteService {

    @GetMapping(value = "/api/location/{id}")
    LocationDto findLocationById(@PathVariable("id") Long id);

}

现在,当用DB中不存在的id调用这个MapsMoteService.findLocationById(id)时,我想检索ExceptionResponse

所以我尝试创建一个ErrorDecoder:

客户端配置:

@Configuration
public class ClientConfiguration {

    @Bean
    public OkHttpClient client() {
        return new OkHttpClient();
    }

    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL;
    }
    
    @Bean
    public ErrorDecoder errorDecoder() {
        return new ClientErrorDecoder();
    }

}

错误解码器:

public class ClientErrorDecoder implements ErrorDecoder {

    @Override
    public Exception decode(String methodKey, Response response) {
        ObjectMapper mapper = new ObjectMapper();
        RemoteServiceException remoteServiceException = null;
        
        // Attempt 1
        try (InputStream inputStream = response.body().asInputStream())  {
            ExceptionResponse exceptionResponse = mapper.readValue(inputStream, ExceptionResponse.class);
            remoteServiceException = buildRemoteServiceException(exceptionResponse);
        } catch (IOException e) {

        }
        
        // Attempt 2
        try (Reader reader = response.body().asReader())  {
            ExceptionResponse exceptionResponse = mapper.readValue(reader, ExceptionResponse.class);
            remoteServiceException = buildRemoteServiceException(exceptionResponse);
        } catch (IOException e) {

        }
        
        // Attempt 3
        try {
            String body = response.body().toString();
            ExceptionResponse exceptionResponse = mapper.readValue(body, ExceptionResponse.class);
            remoteServiceException = buildRemoteServiceException(exceptionResponse);
        } catch (IOException e) {

        }
        
        if(remoteServiceException == null){
            return new ErrorDecoder.Default().decode(methodKey, response);
        }

        return remoteServiceException;
    }
    
    private static RemoteServiceException buildRemoteServiceException(ExceptionResponse exceptionResponse) {
        return new RemoteServiceException(exceptionResponse.getMessage(), exceptionResponse.getUniqueIdentifier());
    }

}

我尝试了我在网上找到的所有东西,但都不起作用。

奇怪的是,我将inputStream作为临时文件保存到资源文件夹中。这是正确的。

我使用以下代码编写文件:

try (InputStream inputStream = response.body().asInputStream())  {
    File targetFile = new File("src/main/resources/targetFile.tmp");

    java.nio.file.Files.copy(
              inputStream, 
              targetFile.toPath(), 
              StandardCopyOption.REPLACE_EXISTING);

    IOUtils.closeQuietly(inputStream);
} catch (IOException e) {
    // return new ErrorDecoder.Default().decode(methodKey, response);
}

这是文件的内容:

{
    "timestamp":"2023-07-25T22:38:48.530815",
    "status":"500",
    "error":"Internal Server Error",
    "uniqueIdentifier":"bc4bd3ae-2d40-4863-9e9f-6b10ecece27d",
    "message":"No Location found with the id: 10",
    "stackTrace":"7711 characters avoided for readability"
}

并且它完美地表示具有6个字段的类ExceptionResponse。

所以在使用时似乎出现了问题

mapper.readValue(inputStream, ExceptionResponse.class);