我有两个方法，我想调用第一个public方法，它反过来会调用一个private方法，在private方法中我想调用一个外部服务，并模拟其中get请求的500个内部服务错误。我知道如何模仿整个私有方法，但这行不通，我想看看在那里发生了什么，特别是当我从外部服务得到一个500回来。
下面是我正在测试的两种方法。。

@Resource(name = "serviceRestTemplate")
private OAuth2RestTemplate serviceRestTemplate;

public ResponseEntity<Cargo> getById(String id) throws MyException {

    UriComponentsBuilder newUri = UriComponentsBuilder
            .fromHttpUrl(url + id + HEADER_URI);
    ResponseEntity<String> responseEntity = this.callNewService(newUri, HttpMethod.GET);
    // more irrelivent code...
}

private ResponseEntity<String> callNewService(UriComponentsBuilder uriBuilder, HttpMethod method) throws MyException {

    ResponseEntity<String> responseEntity = null;
    try {
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        HttpEntity<String> requestEntity = new HttpEntity<>(headers);

        responseEntity = serviceRestTemplate.exchange(uriBuilder.toUriString(),
                method, requestEntity, String.class);

    }catch(HttpClientErrorException httpClientErrorException) {
        LOGGER.error("Error when calling Service. {} ", uriBuilder.toUriString());
        LOGGER.error("Error message from HttpClientErrorException . {} ", httpClientErrorException.getMessage());
        throw buildException(httpClientErrorException.getMessage(), httpClientErrorException.getRawStatusCode());
    }

    if(null != responseEntity
            && responseEntity.getStatusCode().is2xxSuccessful()
            && EDMRESTServiceUtilities.isJsonValid(responseEntity.getBody())) {
        LOGGER.info("Service response: {}", responseEntity.getBody());
        return responseEntity;
    }else {
        LOGGER.error("Error response from Service. {} ", uriBuilder.toUriString());
        throw buildException(SERVICE_ERROR_MESSAGE, HttpStatus.INTERNAL_SERVER_ERROR.value());
    }
}