Android Assets下文件复制到sdcard

/*** Assets下文件复制到sdcard*/private void copyFile() {        AssetManager assetManager = this.getAssets();        InputStream in = null;        OutputStream out = null;        try {            in = assetManager.open("xxxx.mp4");            String newFileName = Environment.getExternalStorageDirectory()+"/xxxx.mp4";            out = new FileOutputStream(newFileName);            byte[] buffer = new byte[1024];            int read;            while ((read = in.read(buffer)) != -1) {                out.write(buffer, 0, read);            }            in.close();            in = null;            out.flush();            out.close();            out = null;        } catch (Exception e) {            Log.e("tag", e.getMessage());        }}