如何使用Java REST Client API部分下载Google驱动器文件? [英] How to partial download google drive files using java REST Client API?

问题描述

使用下面的示例代码(Drive Java REST API V3)，我正在尝试从Google驱动器下载文件的一部分.

Using the sample code (Drive Java REST API V3) below, I am trying to download a portion of a file from google drive.

Drive.Revisions.Get get = service.revisions().get(fileId, revisionId)
            .setFields(FilterConstants.OBJECT_REVISION);

MediaHttpDownloader downloader = get.getMediaHttpDownloader();
downloader.setContentRange(fromByte, toByte);

inputStream = get.executeMediaAsInputStream();

但这对我不起作用.有人可以帮我解决这个问题吗?

But this is not working for me. Can someone help me how to resolve this issue?

推荐答案

以下代码对我有用.诀窍是正确设置Range标头

The following code works for me. The trick was to set Range header correctly

private byte[] getBytes(Drive drive, String downloadUrl, long position, int byteCount) {
    byte[] receivedByteArray = null;
    if (downloadUrl != null && downloadUrl.length() > 0) {
        try {
            com.google.api.client.http.HttpRequest httpRequestGet = drive.getRequestFactory().buildGetRequest(new GenericUrl(downloadUrl));
            httpRequestGet.getHeaders().setRange("bytes=" + position + "-" + (position + byteCount - 1));
            com.google.api.client.http.HttpResponse response = httpRequestGet.execute();
            InputStream is = response.getContent();
            receivedByteArray = IOUtils.toByteArray(is);
            response.disconnect();
            System.out.println("google-http-client-1.18.0-rc response: [" + position + ", " + (position + receivedByteArray.length - 1) + "]");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return receivedByteArray;
}

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