Storing large ArrayLists to SQLite

Question

I im developing a application in which I continuously download large amount of data.

The data in json format and I use Gson to deserialize it. By now Im storing this in a SQLite db. And I have to calculate the relationship and store them into a relationship db. However this takes too much time.

It would be much more convenient to save the class objects to db.

The data looks something like this after deserialization:

Class A{
private String name;
private List<B> subItems;
}

Class B{
private String name;
private List<C> subItems
}

Can I persist this in a easier way, for example by making them serializable? How can this be done?

Caner · Accepted Answer · 2011-10-18 07:28:49Z

7

Yes, serialization is a better solution in your case and it works in Android. The following example is taken from http://www.jondev.net/articles/Android_Serialization_Example_%28Java%29

serialization method:

  public static byte[] serializeObject(Object o) { 
    ByteArrayOutputStream bos = new ByteArrayOutputStream(); 

    try { 
      ObjectOutput out = new ObjectOutputStream(bos); 
      out.writeObject(o); 
      out.close(); 

      // Get the bytes of the serialized object 
      byte[] buf = bos.toByteArray(); 

      return buf; 
    } catch(IOException ioe) { 
      Log.e("serializeObject", "error", ioe); 

      return null;
    }

deserialization method:

  public static Object deserializeObject(byte[] b) { 
    try { 
      ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(b)); 
      Object object = in.readObject(); 
      in.close(); 

      return object; 
    } catch(ClassNotFoundException cnfe) { 
      Log.e("deserializeObject", "class not found error", cnfe); 

      return null; 
    } catch(IOException ioe) { 
      Log.e("deserializeObject", "io error", ioe); 

      return null;
  }

answered Oct 18, 2011 at 7:28

Caner

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6 Comments

johan Over a year ago

Thanks a lot! Do you now how I handle the relationships between the classes. Class A holds a list with Class B. Do I serialize each or just the "top" class?

Caner Over a year ago

Make both classes serializable. I think you just serialize class A.

johan Over a year ago

Ok. And I save them as a blob?

Caner Over a year ago

There is no Blob in Sqlite, but yes it should work I think. Check: sqlite.org/datatype3.html , 2.1.3 for details. You can also save to disk, and example I pointed shows that.

Brijesh Thakur Over a year ago

BTW !!!! Wont it hit performance. If its json. why dont use just use json.ToString() function and store it to DB. and later on using JSONParser you can convert String to JSON.

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