关于处理gzip响应的HttpClient [Java]有点困惑

我的应用程序向某些api服务发出http请求,该服务返回一个gzip压缩响应.如何确保响应确实是gzip格式？我很困惑为什么在提出请求后我没有解压缩它.

以下是我的代码:

public static String streamToString(InputStream stream) {
    BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
    StringBuilder sb = new StringBuilder();
    String line;

    try {
        while ((line = reader.readLine()) != null) {
            sb.append(line).append("\n");
        }
    } catch (IOException e) {
        logger.error("Error while streaming to string: {}", e);
    } finally {
        try { stream.close(); } catch (IOException e) { }
    }

    return sb.toString();
}

public static String getResultFromHttpRequest(String url) throws IOException { // add retries, catch all exceptions
    HttpClient httpclient = new DefaultHttpClient();
    HttpGet httpGet;
    HttpResponse httpResponse;
    InputStream stream;

    try {
        httpGet = new HttpGet(url);
        httpGet.setHeader("Content-Encoding", "gzip, deflate");
        httpResponse = httpclient.execute(httpGet);
        logger.info(httpResponse.getEntity().getContentEncoding());
        logger.info(httpResponse.getEntity().getContent());
        if (httpResponse.getStatusLine().getStatusCode() == 200) {
            stream = httpResponse.getEntity().getContent();
            return streamToString(stream);
        }
    } catch (IllegalStateException e) {
        logger.error("Error while trying to access: " + url, e);
    }

    return "";
}

也许它会自动解压缩,但我希望至少看到一些迹象.