java - 对 HttpClient[Java] 处理 gzip 响应有点困惑

Question

我的应用程序向某个 api 服务发出 http 请求，该服务返回 gzip 压缩响应。如何确保响应确实是 gzip 格式？我很困惑为什么在发出请求后我不必解压缩它。

下面是我的代码:

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 "";
}

也许它正在自动解压缩，但我希望至少看到一些迹象。

Answer 1

嗨，我来晚了，但这个答案可能会被面临同样问题的人使用。默认情况下，内容在响应中解压缩。因此，您必须使用以下代码禁用默认压缩:

CloseableHttpClient client = HttpClients.custom()
    .disableContentCompression()
    .build();

HttpGet request = new HttpGet(urlSring);
request.setHeader(HttpHeaders.ACCEPT_ENCODING, "gzip");

CloseableHttpResponse response = client.execute(request, context);
HttpEntity entity = response.getEntity();
Header contentEncodingHeader = entity.getContentEncoding();

if (contentEncodingHeader != null) {
    HeaderElement[] encodings =contentEncodingHeader.getElements();
    for (int i = 0; i < encodings.length; i++) {
        if (encodings[i].getName().equalsIgnoreCase("gzip")) {
            entity = new GzipDecompressingEntity(entity);
            break;
        }
    }
}

String output = EntityUtils.toString(entity, Charset.forName("UTF-8").name());