如何在android上以文件形式访问保存的位图？

Bitmap bitmap = ...; // 获取位图对象
File file = new File(Environment.getExternalStorageDirectory(), "image.jpg");
try {
    FileOutputStream fos = new FileOutputStream(file);
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
    fos.flush();
    fos.close();
} catch (IOException e) {
    e.printStackTrace();
}

File file = new File(Environment.getExternalStorageDirectory(), "image.jpg");
Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath());

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />