android如何保存对象list到file

//存储
public static void saveObjectsToFile(List<? extends Serializable> objects, String filename) throws IOException {
   File file1 = BaseApplication.getInstance()
         .getApplicationContext().getExternalFilesDir("");
   File appDir = new File(file1, filename);
   if (!appDir.exists()) {
      appDir.mkdirs();
   }
   String dataName =filename+".txt" ;
   File file = new File(appDir, dataName);
   ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(file));
   out.writeObject(objects);
   out.close();
}
//读取
@SuppressWarnings("unchecked")
public static List<MyObject> loadObjectsFromFile(String filename) throws IOException, ClassNotFoundException {
   File file1 = BaseApplication.getInstance()
         .getApplicationContext().getExternalFilesDir("");
   File appDir = new File(file1, filename);
   String dataName =filename+".txt" ;
   File file = new File(appDir, dataName);
   ObjectInputStream in = new ObjectInputStream(new FileInputStream(file));
   List<MyObject> objects = (List<MyObject>) in.readObject();
   in.close();
   return objects;
}
//序列化
public class MyObject implements Serializable {
}