以编程方式检查下载的MP3/OGG文件在android中是否有效/完整

Question

我下载音频文件MP3/OGG从用户提供的网址以编程方式。我进一步将继续设置下载的文件为铃声/闹铃。但是，我需要以编程方式验证下载的文件是有效的MP3/OGG文件，并且是可播放的。有什么方法可以确保已下载的文件是有效的MP3/OGG文件，而不是来自假网址的垃圾头。

我用来下载的代码：

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

我通过使用MediaMetadataRetriever classe的API“提取元数据（MediaMetadataRetriever.METADATA_KEY_DURATION）”。如果它是一个有效的mp3/ogg文件，则返回有效的持续时间。否则，我捕获一个运行时异常并从我的API返回。

Answer 2

您可以检查下载流的结尾，如果它被调用，它表示您下载的文件的完整长度。如果这个答案对你有效，你会接受吗？谢谢