public class DataSource implements DataSourceListener {
          public static final String TAG = "DataSource";
           private Context context;
           public   DataSource (Context context){
               this.context=context;
            }
           @Override
           public com.google.android.exoplayer2.upstream.DataSource.Factory getDataSourceFactory() {
                OkHttpClient  okHttpClient = new OkHttpClient();
               OkHttpDataSourceFactory OkHttpDataSourceFactory=    new OkHttpDataSourceFactory(okHttpClient, Util.getUserAgent(context, context.getApplicationContext().getPackageName()),new DefaultBandwidthMeter() );
                   //使用OkHttpClient 数据源工厂
                 //return  OkHttpDataSourceFactory; ;
                 //默认数据源工厂
                 // return new JDefaultDataSourceFactory(context);
                 // Rtmp数据源工厂 对 Rtmp 协议支持
                 // return  new RtmpDataSourceFactory();
                //缓存使用和组合使用
                 LeastRecentlyUsedCacheEvictor evictor = new LeastRecentlyUsedCacheEvictor(1000000000);
                SimpleCache   simpleCache = new SimpleCache(new File(context.getCacheDir(), "media"), evictor);
                //缓存数据源使用，内部使用DefaultDataSourceFactory数据源工厂类
                // return  new CacheDataSinkFactory(simpleCache,10000);
                // 配合okHttp数据源工厂类
                return  new CacheDataSourceFactory(simpleCache, OkHttpDataSourceFactory);
                //使用配合默认数据源红工厂类
               // return  new CacheDataSourceFactory(simpleCache, new JDefaultDataSourceFactory(context));
                //使用提供缓存数据源工厂类
               // return new CacheDataSourceFactory(context,1000,1000);
              }
    }