Question

The following code prints the following as input, but I would like to pass this JSON string as input directly to parse method (preferably as string argument). How should I do that?

{“val1″:”v1″,”val2″:”v2”}

import com.google.gson.*;

public class ParseJSON {

    String val1;
    String val2;
    transient String val3;

    public static void main(String[] args) {
        Gson gson = new GsonBuilder().create();
        ParseJSON parseJson = new ParseJSON();
        parseJson.val1 = "v1";
        parseJson.val2 = "v2";
        parseJson.val3 = "v3";
        String requestBody = gson.toJson(parseJson);
        System.out.println(requestBody);

        JsonParser parser = new JsonParser();
        // JsonArray array = parser.parse(requestBody).getAsJsonArray();
    }
}

Answer 1

The JSON that is being created would be considered a JSON object, not an array. To parse it correctly, you would need to call:

JsonObject object = parser.parse(requestBody).getAsJsonObject();

A JSON array would look more like this:

[{"va1": "v1", "val2": "v2", "val3": "v3"}, {"val4": "v4", "val4": "v5", "val5": "v6"}]

That’s a JSON array containing two JSON objects. JSON arrays have similar style to arrays you see in Java, they have [ ] brackets and contain a comma separated list of objects/arrays/primitives.

Additionally, you can parse it like this as well:

JsonElement element = parser.parse(requestBody);

Once you have a JsonElement you can call methods like isJsonArray() or isJsonObject() to find out what the top level JSON element is for the String you’ve parsed.