获取RestClientException：尝试从API解析json响应时无法提取响应

Question

我还是Java和Springboot的新手，每次我尝试发送API请求时，我都会卡住。

这是我尝试解析的示例API响应-

{
    "respCode": "0",
    "statusCode": "0"
}

以下是代码-

MultiValueMap<String, String> body = new LinkedMultiValueMap<>();

    body.add("merchantTxnId", enqr.getMerchantTxnId());
    body.add("pgTxnId", enqr.getPgTxnId());
    RestTemplate restTemplate = RestTemplateClient.getRestTemplate(30, 30);

    String signature = "some signature";
    HttpHeaders headers = new HttpHeaders();
    headers.set("Content-Type","application/json");
    headers.set("access_key", accessKey);
    headers.set("signature", signature);
    headers.set("Accept", "application/json");

    HttpEntity<MultiValueMap<String, String>> entity = new 
    HttpEntity<MultiValueMap<String, String>>(
            body, headers);

   String url = UriBuilder.fromPath(baseUrl).path("/refund")
                .toString();

   try {
        @SuppressWarnings("rawtypes")
        ResponseEntity<Map> ent = restTemplate.exchange(url,
                HttpMethod.POST, entity, Map.class);
        if (!ent.getBody().get("statusCode").equals("0"))
            throw new Exception((String) ent.getBody().get("respMsg"));
    } catch (Exception ex) {
        logger.info("CouldNot Refund to Source due to {}", ex.getMessage());
        return false;
    }

在exchange()通话中出现异常-

org.springframework.web.client.RestClientException: Could not extract response: no suitable HttpMessageConverter found for response type [interface java.util.Map] and content type [application/octet-stream]