Spring-boot Resttemplate response.body is null while interceptor clearly shows body

Question

With Spring-boot 1.5.10.RELEASE, I am getting response.body as null.

Here is how I am using RestTemplate

RestTemplate restTemplate = new RestTemplate();
    List<ClientHttpRequestInterceptor> interceptors = new ArrayList<>();
    interceptors.add(new LoggingRequestInterceptor());
    restTemplate.setInterceptors(interceptors);

    String url = "http://someurl/Commands";

    MultiValueMap<String, String> params = new LinkedMultiValueMap<>();
    params.add("cmd", "{\"operation\":\"getSomeDetails\"}}");

    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
    HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<>(params, headers);

    ResponseEntity<String> response = restTemplate.postForEntity(url, request, String.class);

    System.out.println("This is always null: " + response.getBody());

While above program always prints null, following interceptor prints valid response body

public class LoggingRequestInterceptor implements ClientHttpRequestInterceptor {

final static Logger log = LoggerFactory.getLogger(LoggingRequestInterceptor.class);

@Override
public ClientHttpResponse intercept(final HttpRequest request, final byte[] body,
                                    final ClientHttpRequestExecution execution) throws IOException {
    traceRequest(request, body);
    ClientHttpResponse response = execution.execute(request, body);
    traceResponse(response);
    return response;
}


private void traceResponse(ClientHttpResponse response) throws IOException {
    StringBuilder inputStringBuilder = new StringBuilder();
    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(response.getBody(), "UTF-8"));
    String line = bufferedReader.readLine();
    while (line != null) {
        inputStringBuilder.append(line);
        inputStringBuilder.append('\n');
        line = bufferedReader.readLine();
    }
    log.debug("============================response begin==========================================");
    log.debug("Status code  : {}", response.getStatusCode());
    log.debug("Status text  : {}", response.getStatusText());
    log.debug("Headers      : {}", response.getHeaders());
    log.debug("Response body: {}", inputStringBuilder.toString());
    log.debug("=======================response end=================================================");
}

}

Answer 1

You're consuming the response body in traceResponse; that's your problem. Also, please update your question to be specific; "all latest" means nothing. What's latest today isn't so tomorrow.