How to save and retrieve InputStream in text file with less overhead

Question

I am retrieving/downloading JSON feed as InputStreamReader and I need to pass this InputStreamReader to JsonReader for parsing it.

JsonReader reader = new JsonReader(isr); // isr is the InputStreamReader instance

Everything is okay. But I want to cache this InputStreamReader or this data in some other format into internal storage for later use. For caching, I am using text file to save. (AFAIK, android default cache saves data in external storage and some devices have no external storage).

For saving this file, I am using .txt file. But I am only able to save/cache String formatted data into file and read it as String. This is the code what I have written so far to write & read file:

public static void writeObject(Context context, String key, Object object)
        throws IOException {
    FileOutputStream fos = context
            .openFileOutput(key, Context.MODE_PRIVATE);
    ObjectOutputStream oos = new ObjectOutputStream(fos);
    oos.writeObject(object);
    oos.close();
    fos.close();
}

public static Object readObject(Context context, String key)
        throws IOException, ClassNotFoundException {
    FileInputStream fis = context.openFileInput(key);
    ObjectInputStream ois = new ObjectInputStream(fis);
    Object object = ois.readObject();
    return object;
}

But this approach is taking too much conversion:

inputStreamReader -> inputStream -> String //to save
String -> inputStream -> inputStreamReader // retrieve  

How can Save/cache this data with less overhead? Perhaps inputStreamReader needs to be converted to outputStreamReader or something like this to be writable. But I can't figure out the associative code to do this. What should be the code? Also can I cache this data by android's proposed way for later use intead of saving it as .txt file?

Answer 1

You can't short this process as String is best format to save information in file AFAIK. Also inputStreamReader & inputStream are not suitable object to be written. There may be other better explanatory answer :)