如何使用Java在android中使用http请求下载公共Google驱动器文件？

Question

我尝试了很多方法来下载Google Drive公共文件但找不到任何答案？ 如果有人知道该怎么做，请帮助我。

注意：不使用 Google Drive api

Answer 1

大多数文件（文档、工作表、演示文稿等）都可以通过将 URL 中的 edit 替换为 export?format= 来下载。

https://docs.google.com/document/d/FILE-ID/edit
https://docs.google.com/document/d/FILE-ID/export?format=doc

有很多格式可用（pdf/doc/pptx/xlsx/csv/jpg/等...）

上述解决方案通常适用于 pdf、图像、原生谷歌文件和微软 Office 文件。但是，如果您是 尝试下载其他类型的文件，您可以使用下一个 URL。

https://drive.google.com/uc?export=download&id=FILE-ID

更多网址技巧在这里

Answer 2

    // Tested with a google drive public link. Successfully downloaded.
    // Change the suffix of the Google Drive link from /edit to /export?format=csv
    // A sample link :
    // https://docs.google.com/spreadsheets/d/XYZ/export?format=csv
    // 
    public static boolean downloadWithRedirect(String downloadUrl, String storagePath){
    InputStream input = null;
    OutputStream output = null;
    try {
        URL obj = new URL(downloadUrl);
        HttpURLConnection conn = (HttpURLConnection) obj.openConnection();
        conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
        conn.addRequestProperty("User-Agent", "Mozilla");
        conn.addRequestProperty("Referer", "google.com");
        conn.setReadTimeout(5000);
        conn.setConnectTimeout(5000);

        boolean redirect = false;

        // normally, 3xx is redirect
        int status = conn.getResponseCode();
        if (status != HttpURLConnection.HTTP_OK) {
            if (status == HttpURLConnection.HTTP_MOVED_TEMP
                    || status == HttpURLConnection.HTTP_MOVED_PERM
                    || status == HttpURLConnection.HTTP_SEE_OTHER)
                redirect = true;
        }

        if (redirect) {
            // get redirect url from "location" header field
            String newUrl = conn.getHeaderField("Location");

            // get the cookie if need, for login
            String cookies = conn.getHeaderField("Set-Cookie");

            // open the new connnection again
            conn = (HttpURLConnection) new URL(newUrl).openConnection();
            conn.setRequestProperty("Cookie", cookies);
            conn.addRequestProperty("Accept-Language", "en-US,en;q=0.8");
            conn.addRequestProperty("User-Agent", "Mozilla");
            conn.addRequestProperty("Referer", "google.com");
            conn.setReadTimeout(5000);
            conn.setConnectTimeout(5000);

            Log.i(TAG, "[downloadWithRedirect] Redirect to URL : " + newUrl);

        }

        input = new BufferedInputStream(conn.getInputStream(), 1024 * 8);
        output = new FileOutputStream(storagePath);

        // Ensure output directory exists.
        File outputFile = new File(storagePath);
        FileUtil.mkDirs(new File(outputFile.getParent()));

        Log.i(TAG, "[download] url:" + downloadUrl + ", storagePath:" + storagePath + ", download stream length in bytes:" + conn.getContentLength());
        writeToOutputStream(input, output);

        return isFileValid(storagePath);

    } catch (Exception e) {
        Log.e(TAG, "[downloadWithRedirect] Download failed. " + downloadUrl + " " + e.getMessage(), e);
        return false;
    } finally {
        try{if(output != null) output.close();}catch(Exception e){}
        try{if(input != null) input.close();}catch(Exception e){}            
    }
}

 private static void writeToOutputStream(InputStream is, OutputStream os) throws IOException {
    byte[] buffer = new byte[1024 * 8];
    int length;
    if (is != null) {
        while ((length = is.read(buffer)) > 0x0) {
            os.write(buffer, 0x0, length);
        }
    }
    os.flush();
}