How can I use an object inside a HashMap when parsing multidimensional JSON with GSON in JAVA?

Question

If I have JSON DATA like:

{
   "status":200,

   "carList":[
       {
          "carId":121,
          "carName":"Cat",
      },
      {
         "carId":122,
         "carName":"Snek",
      }
   ]
}

I want to Use GSON to create the objects by:

Cars cars = gson.fromJson(api.response(), Cars.class);

Using the two classes like this:

Class Cars{
    public String status;
    public Hashmap<String, Car> carList;
}

Class Car{
    public String carId;
    public String carName;
}

From what I am reading my problem is putting an object inside of the HashMap.

At the end of the day I need to be able to loop the "carLis" to display it in a table but I am not sure what my approach should be.

A JSON array won't map to a `HashMap`. Change it to a `List`. Let your clients generate the `HashMap` or expose it separately. — Sotirios Delimanolis, Aug 22 '17 at 22:37
@SotiriosDelimanolis How do you know when to use a list or an array list like siriraghavan says? — silversunhunter, Aug 22 '17 at 23:42
See my answer [here](https://stackoverflow.com/a/33621809/438154). — Sotirios Delimanolis, Aug 22 '17 at 23:48

score 1 · Accepted Answer · answered Aug 22 '17 at 22:41

1

carList is an Array of Objects and not a hashmap. Try changing the type of carList to ArrayList

Class Cars{
    public String status;
    public ArrayList<Car> carList;
}

You can loop over the ArrayList for the elements

answered Aug 22 '17 at 22:41

Sriraghavan Subramanian

357
3
12

Thank you! this is what I needed to do! – silversunhunter Aug 22 '17 at 23:41

How can I use an object inside a HashMap when parsing multidimensional JSON with GSON in JAVA?

1 Answers1