spring - 为什么我的自定义 ClientHttpRequestInterceptor 响应为空

Question

我已经为我的自定义日志拦截器完成了以下操作

public class HttpLoggingInterceptor implements ClientHttpRequestInterceptor {
    private final static Logger log = LoggerFactory.getLogger(HttpLoggingInterceptor.class);

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

    private void logRequest(HttpRequest request, byte[] body) throws IOException {
        log.info("Request URI : {}, Method : {}, Headers : {}, Request body : {}", request.getURI(), request.getMethod(), request.getHeaders(), new String(body, "UTF-8"));

    }

    private void logResponse(ClientHttpResponse response) throws IOException {
        log.info("Response Status code : {}, Status text : {}, Headers : {}, Response body: {}", response.getStatusCode(), response.getStatusText(), response.getHeaders(), StreamUtils.copyToString(response.getBody(), Charset.defaultCharset()));
    }
}

我将拦截器设置为restTemplate

   @Autowired
    public RestTemplate restTemplate;

    @Override
    public void onApplicationEvent(ApplicationReadyEvent event) {
        List<ClientHttpRequestInterceptor> clientHttpRequestInterceptors = new ArrayList<>();
        clientHttpRequestInterceptors.add(new HttpLoggingInterceptor());
//        clientHttpRequestInterceptors.addAll(restTemplate.getInterceptors());
        restTemplate.setInterceptors(clientHttpRequestInterceptors);
//        restTemplate.setInterceptors(Collections.singletonList(new HttpLoggingInterceptor()));
}

记录器正在将响应正确打印到控制台，但最终响应将作为空返回给调用者。我无法调试并弄清楚它。

我发现 StreamUtils.copyToString(response.getBody(), Charset.defaultCharset()) 正在读取输入流一次，并且不再在其中保存响应正文(现在是空的)

还有其他人也面临同样的问题，并且有任何想法复制输入流而不从原始输入流中读取它吗？

Answer 1

由于输入流只能使用一次，并且 sun.net 没有可用的 reset() 或 mark(***) 函数。 www.protocol.http.HttpURLConnection$HttpInputStream.

只有一种方法可以多次读取响应，即通过以下方式创建restTemplate。

@Bean
public RestTemplate getfxoWsClientRestTemplate(){
    RestTemplate restTemplate = new RestTemplate(new BufferingClientHttpRequestFactory(new SimpleClientHttpRequestFactory()));
    restTemplate.setInterceptors(Collections.singletonList(new HttpLoggingInterceptor()));
    return  restTemplate;
}

而LoggingIntercepter可以这样写

public class HttpLoggingInterceptor implements ClientHttpRequestInterceptor {

    private final static Logger logger = LoggerFactory.getLogger(HttpLoggingInterceptor.class);

    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
    logger.info("request method: {}, request URI: {}, request headers: {}, request body: {}",
            request.getMethod(), request.getURI(), request.getHeaders(), new String(body, Charset.forName("UTF-8")));

    ClientHttpResponse response = execution.execute(request, body);

    logger.info("response status code: {}, response headers: {}, response body: {}",
            response.getStatusCode(), response.getHeaders(), new String(ByteStreams.toByteArray(response.getBody()), Charset.forName("UTF-8")));

    return response;
}

}