如何将大文件从 URL 保存到本地

Question

我在下面的代码中尝试了这个，它在小文件中运行良好。URL url = new URL(downloadLink);ReadableByteChannel rbc = Channels.newChannel(url.openStream());FileOutputStream fos = new FileOutputStream(newFile);fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);fos.close();rbc.close();如果文件是大文件，则会出现如下错误：java.io.IOException:Server returned HTTP response code: 400 for URL:https://dl.dropboxusercontent.com/1/view/79q8i6f9zqx7y2w/Paragliding in Himalayas.avi谁能帮我。

Answer 1

您尝试下载的 URL 无效。URL 不能包含空格。您需要对其进行 URL 编码：

https://dl.dropboxusercontent.com/1/view/79q8i6f9zqx7y2w/Paragliding%20in%20Himalayas.avi

看看：如何正确编码完整的 http url 字符串？，用于对 URL 进行编码的方法。不幸的是，只是使用URLEncoder.encode()不会削减它，因为它编码斜杠等。

Answer 2

您可以使用 DownloadManager 将此任务交给 Os 本身

 private fun startDownload(url: String) {

    val request = DownloadManager.Request(Uri.parse(url))

    request.allowScanningByMediaScanner()

    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)

    request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, url.substring(url.lastIndexOf("/")))

    val dm = activity!!.getSystemService(DOWNLOAD_SERVICE) as DownloadManager

    dm.enqueue(request)

    Toast.makeText(getApplicationContext(), "Downloading File", Toast.LENGTH_LONG).show()

}