import com.google.android.exoplayer2.upstream.FileDataSourceFactory; //导入依赖的package包/类
private void prepareAudioFile(File file, long startPositionMs) {
    Uri fileUri = Uri.fromFile(file);

    DataSource.Factory dataSourceFactory = new FileDataSourceFactory();
    DefaultExtractorsFactory extractorsFactory = new DefaultExtractorsFactory();
    extractorsFactory.setMp3ExtractorFlags(Mp3Extractor.FLAG_ENABLE_CONSTANT_BITRATE_SEEKING);
    MediaSource source = new ExtractorMediaSource(
            fileUri, dataSourceFactory, extractorsFactory, null, null);

    exoPlayer.seekTo(startPositionMs);
    exoPlayer.prepare(source, false, true);
}
 

import com.google.android.exoplayer2.upstream.FileDataSourceFactory; //导入依赖的package包/类
/**
 * @see CacheDataSource#CacheDataSource(Cache, DataSource, int, long)
 */
public CacheDataSourceFactory(Cache cache, DataSource.Factory upstreamFactory,
    @CacheDataSource.Flags int flags, long maxCacheFileSize) {
  this(cache, upstreamFactory, new FileDataSourceFactory(),
      new CacheDataSinkFactory(cache, maxCacheFileSize), flags, null);
}
 

import com.google.android.exoplayer2.upstream.FileDataSourceFactory; //导入依赖的package包/类
protected DataSource.Factory buildFileDataSourceFactory(boolean useBandwidthMeter) {
    return new FileDataSourceFactory(useBandwidthMeter ? BANDWIDTH_METER : null);
}
 

import com.google.android.exoplayer2.upstream.FileDataSourceFactory; //导入依赖的package包/类
/**
 * @see CacheDataSource#CacheDataSource(Cache, DataSource, int, long)
 */
public CacheDataSourceFactory(Cache cache, DataSource.Factory upstreamFactory, int flags,
    long maxCacheFileSize) {
  this(cache, upstreamFactory, new FileDataSourceFactory(),
      new CacheDataSinkFactory(cache, maxCacheFileSize), flags, null);
}
 

import com.google.android.exoplayer2.upstream.FileDataSourceFactory; //导入依赖的package包/类
@Override
protected ExtractorMediaSource.Factory create() throws Throwable {
	final ExtractorMediaSource.Factory factory = new ExtractorMediaSource.Factory(new FileDataSourceFactory());
	factory.setMinLoadableRetryCount(ExtractorMediaSource.DEFAULT_MIN_LOADABLE_RETRY_COUNT_LIVE);
	return factory;
}