Spring-boot Resttemplate response.body 为空，而拦截器清楚地显示 body

Question

使用Spring-boot 1.5.10.RELEASE，我得到的response.body为空。

这是我如何使用 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());

虽然上面的程序总是打印空，以下侦听器打印有效的响应正文

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

虽然接受的答案有原因，但我相信解决方案也是必要的。

Spring 有一个 BufferingClientHttpRequestFactory，它充当 Rest 模板默认 SimpleClientHttpRequestFactory 的包装器。它可以在创建过程中传递给 Rest 模板。这会强制 Rest 模板使侦听器使用响应的副本，而不是销毁它。

ClientHttpRequestFactory factory = new BufferingClientHttpRequestFactory(new SimpleClientHttpRequestFactory());
RestTemplate restTemplate = new RestTemplate(factory);

源：http://objectpartners.com/2018/03/01/log-your-resttemplate-request-and-response-without-destroying-the-body/

Answer 2

你在traceResponse中使用响应体; 那是你的问题。另外，请更新您的问题以使其具体;"所有最新"没有任何意义。今天的最新情况明天就不是这样了。

Answer 3

下面的代码将解决问题。

@Bean public RestTemplate restTemplate() {
final RestTemplate restTempate = new RestTemplate(new BufferingClientHttpRequestFactory(new
                  SimpleClientHttpRequestFactory()));
final List<ClientHttpRequestInterceptor> interceptors = new ArrayList<>();
interceptors.add(new LogHttpInterceptor());
restTempate.setInterceptors(interceptors);
return restTemplate;}

虽然日志拦截器如下所示

public class LogHttpInterceptor implements ClientHttpRequestInterceptor {
final static Logger log = LoggerFactory.getLogger(LogHttpInterceptor.class);
@Override
public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
    traceRequest(request, body);
    ClientHttpResponse response = execution.execute(request, body);
    traceResponse(response);
    return response;
}
private void traceRequest(HttpRequest request, byte[] body) throws IOException {
    log.info("===========================================================================request begin");
    log.debug("URI         : {}", request.getURI());
    log.debug("Method      : {}", request.getMethod());
    log.debug("Headers     : {}", request.getHeaders() );
    log.debug("Request body: {}", new String(body, "UTF-8"));
    log.info("=============================================================================request end");
}
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.info("==========================================================================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.info("===========================================================================response end");
}

如果不起作用，请告诉我

Answer 4

经过一段时间的搜索，我尝试使用 HttpComponentsClientHttpRequestFactory(( 而不是 SimpleClientHttpRequestFactory((

ClientHttpRequestFactory factory = new BufferingClientHttpRequestFactory(new HttpComponentsClientHttpRequestFactory());

这为我解决了问题。

Answer 5

像这样创建你的 RestTemplate

@Bean
    public RestTemplate interceptedRestTemplate() {
        RestTemplate restTemplate = new RestTemplate(new BufferingClientHttpRequestFactory(
                new SimpleClientHttpRequestFactory()
        ));
        restTemplate.setInterceptors(List.of(<i>your interceptor</i>));
        return restTemplate;
    }

为我工作。