I am using RestClient (not Template!) to send a request to another server. Because of a missing header i get a 400 Error but can not read the body. When i make the request with postman i get a body “header XY missing” i need this Error in my Programm, so i need a way to read/log the body.

public boolean myMethod(String body, String baseUrl, String token) {
    return restClient.post()
            .uri(baseUrl + "/myEndpoint")
            .headers(
                    httpHeaders -> {
                        httpHeaders.set("Calling-Application", "IGPR");
                        httpHeaders.set("Content-Type", "application/json");
                        httpHeaders.set("Locale", "deu-DEU");
                        httpHeaders.set("Authorization", "Bearer " + token);
                    })
            .body(body)
            .exchange((req, res) -> {
                try {
                    if (res.getStatusCode().is2xxSuccessful()) {
                        return true;
                    }
                } catch (HttpClientErrorException e) {
                    e.printStackTrace();
                } catch ( IOException  re ){    //not working! 
                    System.out.println(res.getBody());
                }
                return false;
            });
}

Here is the Loggin Interceptor which should print out the body but due to unknown reasons the interceptor cant print it

public class RequestResponseLoggingInterceptor implements ClientHttpRequestInterceptor {

private final Logger log = LoggerFactory.getLogger(this.getClass());

@Override
public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
    logRequest(request, body);
    ClientHttpResponse response = execution.execute(request, body);
    BufferedClientHttpResponseWrapper responseWrapper = new BufferedClientHttpResponseWrapper(response);
    logResponse(responseWrapper);
    return responseWrapper;
}

private void logRequest(HttpRequest request, byte[] body) throws IOException {
    log.debug("===========================request begin================================================");
    log.debug("URI         : {}", request.getURI());
    log.debug("Method      : {}", request.getMethod());
    log.debug("Headers     : {}", request.getHeaders());
    log.debug("Request body: {}", new String(body, StandardCharsets.UTF_8));
    log.debug("==========================request end================================================");
}

private void logResponse(ClientHttpResponse response) throws IOException {
    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: {}", StreamUtils.copyToString(response.getBody(), Charset.defaultCharset()));
    log.debug("=======================response end=================================================");
}

}

public class BufferedClientHttpResponseWrapper implements ClientHttpResponse {

private final ClientHttpResponse response;
private byte[] body;

public BufferedClientHttpResponseWrapper(ClientHttpResponse response) throws IOException {
    this.response = response;
    this.body = StreamUtils.copyToByteArray(response.getBody());
}

@Override
public InputStream getBody() throws IOException {
    return new ByteArrayInputStream(body);
}


@Override
public String getStatusText() throws IOException {
    return response.getStatusText();
}

@Override
public void close() {
    response.close();
}

@Override
public org.springframework.http.HttpHeaders getHeaders() {
    return response.getHeaders();
}

@Override
public HttpStatusCode getStatusCode() throws IOException {
    return response.getStatusCode();
}

}