Converting byte[] to json and vice versa without jackson or gson

If it would be so easy, then Jackson or Gson was never be born.

I am affraid, that you have to declared deserializer for all of your objects manualy. This is not a rocket science, but it takes time to do it. This is an example:

public static void main(String[] args) {
    Data data = new Data(11, 12);
    String json = toJson(data);
    System.out.println(json);

    byte[] bytes = json.getBytes(StandardCharsets.UTF_8);
    Data res = toDataObj(bytes);
    System.out.println(res.a);
    System.out.println(res.b);
}

public static String toJson(Data data) {
    JSONObject jsonObj = new JSONObject();
    jsonObj.put("a", data.a);
    jsonObj.put("b", data.b);
    return jsonObj.toString();
}


public static Data toDataObj(byte[] bytesClass) {
    JSONObject jsonObject = new JSONObject(new String(bytesClass, StandardCharsets.UTF_8));
    Data data = new Data(0, 0);
    data.a = jsonObject.getInt("a");
    data.b = jsonObject.getInt("b");
    return data;
}

public static class Data {

    int a;
    int b;

    public Data(int a, int b) {
        this.a = a;
        this.b = b;
    }
}

Here you can get more info:

• How to create JSON Object using String?
• How to parse JSON in Java