Question

我正在以编程方式从用户提供的URL下载音频文件MP3 / OGG。我还将继续将下载的文件设置为铃声/闹钟铃声。但是，我需要以编程方式验证下载的文件是否是有效的MP3 / OGG文件并且可以播放。我可以通过哪种方式确保已下载的文件是有效的MP3 / OGG文件，而不是伪URL的垃圾邮件头。

我正在使用的代码：

try {
        URL url = new URL(link);
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setRequestMethod("GET");
        httpConn.setReadTimeout(20000);
        httpConn.setConnectTimeout(10000);
        httpConn.connect();
        int responseCode = httpConn.getResponseCode();
        if (responseCode != HttpURLConnection.HTTP_OK) {
            Log.i(TAG, "http response error code "+responseCode+" for "+name);
            return -1;
        }

        int lenghtOfFile = httpConn.getContentLength();
        Log.d(TAG, "Length of file to download: " + lenghtOfFile + " for " + name + " id_download "+id_download);
        if (lenghtOfFile == -1) {
            return -1; // no length to download
        }
        // input stream to read file - with 8k buffer
        input = new BufferedInputStream(httpConn.getInputStream(),1000000);

        // Delete the outfile first
        File deleteFile = new File(outfile);
        if (deleteFile.exists()) {
            if (deleteFile.delete())
                Log.i(TAG, "File deleted " + outfile);
            else
                Log.i(TAG, "File could'nt be deleted " + outfile);
        }

        output = new FileOutputStream(outfile);
        byte data[] = new byte[1000000];

        long total = 0;
        int progress = 0;
        long mLastUpdate = 0;

        int count = 0;
        while ((count = input.read(data)) != -1) {
            total += count;
            progress = (int) ((total * 100) / lenghtOfFile);
            Log.d(TAG, name + " progress " + progress+"  count "+count+" total "+total);
            output.write(data, 0, count);
            if (System.currentTimeMillis() - mLastUpdate > 1000) {
                mLastUpdate = System.currentTimeMillis();
            }
        }

        output.flush();
    } catch (Exception e) {
        Log.e(TAG, "Exception in downloadUrl() " + e + " for " + name + "  " + id_download + "  "+task_id);
        return -1;
    } finally {
        try {
            if (output != null) {
                output.close();
            }
            if (input != null) {
                input.close();
            }
            if (httpConn != null) {
                httpConn.disconnect();
            }
        } catch (Exception ex) {
            Log.e(TAG,"Exception in close "+ex);
        }
    }

Answer 1

您可以检查下载流的结束，如果它被调用，它是一个指示，您的文件是否已完整下载。如果它适合你，接受这个答案？谢谢

Answer 2

我通过使用MediaMetadataRetriever classe的API＆＃34; extractMetadata（MediaMetadataRetriever.METADATA_KEY_DURATION）＆＃34;解决了这个问题。如果它是有效的mp3 / ogg文件，则返回有效持续时间。否则，我会捕获运行时异常并从我的API返回。

如果下载的MP3 / OGG文件在android中有效/完整，请以编程方式检查

2 个答案: