What is the most suitable Java data structure for representing JSON?

Question

I' m developing a RESTful Android mobile client. Information exchange between my app and server is in JSON. So I' m now a little bit confused what data structure choose for represent JSON responses and data because there a lot of them. I've just stopped with LinkedHashMap<> but as far as i know JSON is unordered. Across the Internet I saw people use Map<> or HashMap<> for this.

So the question - what is the best data structure for this purpose? Or if there is no a univocal answer - pros and cons of using data structures I' ve mentioned.

Answer 1

I would disagree with the first answer. The REST paradigm was developed so that you would operate with objects, rather than operations.

For me the most sensible approach will be if you declare beans on the client side and parse the json responses and request through them. I would recommend using the GSON library for the serialization/ deserialization. JsonObject/ JsonArray is almost never the best choice.

Maybe if you give examples of the operations you are about to use we might be able to help more precisely.

EDIT: Let me also give a few GSON Examples. Let's use this thread to compare the different libraries.

In the most cases REST services communicate objects. Let's assume you make a post of product, which has reference to shop.

{ "name": "Bread",
  "price": 0.78,
  "produced": "08-12-2012 14:34",
  "shop": {
     "name": "neighbourhood bakery"
  }
}

Then if you declare the following beans:

public class Product {
    private String name;
    private double price;
    private Date produced;
    private Shop shop;
    // Optional Getters and setters. GSON uses reflection, it doesn't need them
    // However, better declare them so that you can access the fields
}

public class Shop {
   private String name;
    // Optional Getters and setters. GSON uses reflection, it doesn't need them
    // However, better declare them so that you can access the fields
}

You can deserialize the json using:

String jsonString; // initialized as you can
GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.setDateFormat("MM-dd-yyyy HH:mm"); // setting custom date format
Gson gson = gsonBuilder.create();
Product product = gson.fromJson(jsonString, Product.class);
// Do whatever you want with the object it has its fields loaded from the json

On the other hand you can serialize to json even more easily:

GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.setDateFormat("MM-dd-yyyy HH:mm"); // setting custom date format
Gson gson = gsonBuilder.create();
String jsonString = gson.toJson(product);