java从服务器下载大文件需要很长时间

Question

我正在尝试从Kaltura下载文件（.mp4），文件超过100mb，下面的代码需要花很多时间下载

还有其他方法可以改进吗

try {
        URL url = new URL("https://www.kaltura.com/p/....");
        InputStream in = new BufferedInputStream(url.openStream());
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        byte[] buf = new byte[8192];
        int n = 0;
        while (-1 != (n = in.read(buf)))
        {
            out.write(buf);
        }
        out.close();
        in.close();     
        res.setContentType("application/octet-stream");
        res.setHeader("Cache-Control", "no-cache");
        res.setHeader("Content-Disposition","attachment;filename=Smac_03_48.mp4 (iPad).mp4");
        res.setStatus(200);
        res.getOutputStream().write(out.toByteArray());
    } catch (Exception e) {
        e.printStackTrace();
    }