import org.apache.hadoop.yarn.webapp.RemoteExceptionData; //导入依赖的package包/类
@Override
public Response toResponse(Exception e) {
  // Don't catch this as filter forward on 404
  // (ServletContainer.FEATURE_FILTER_FORWARD_ON_404)
  // won't work and the web UI won't work!
  if (e instanceof com.sun.jersey.api.NotFoundException) {
    return ((com.sun.jersey.api.NotFoundException) e).getResponse();
  }
  // clear content type
  response.setContentType(null);

  // Map response status
  String logPrefix = "Http request failed due to: ";
  final int statusCode;
  if (e instanceof NotFoundException) {
    LOGGER.logInfo(e, logPrefix + "Not Found");
    statusCode = HttpStatus.SC_NOT_FOUND;
  } else if (e instanceof BadRequestException ||
      e instanceof JsonProcessingException ||
      e instanceof WebApplicationException) {
    LOGGER.logInfo(e, logPrefix + "Bad Request");
    statusCode = HttpStatus.SC_BAD_REQUEST;
  } else if (e instanceof ThrottledRequestException) {
    LOGGER.logInfo(e, logPrefix + "Throttled Request");
    statusCode = WebCommon.SC_TOO_MANY_REQUESTS;
  } else {
    LOGGER.logWarning(e, logPrefix + "Service Unavailable");
    statusCode = HttpStatus.SC_SERVICE_UNAVAILABLE;
  }

  // let jaxb handle marshalling data out in the same format requested
  RemoteExceptionData exception = new RemoteExceptionData(
      e.getClass().getSimpleName(),
      StringUtils.stringifyException(e),
      e.getClass().getName());

  return Response.status(statusCode).entity(exception)
      .build();
}