如何获取gson对象的索引？

import com.google.gson.Gson;

public class GsonIndexExample {
    public static void main(String[] args) {
        String json = "{\"name\":\"John\",\"age\":30,\"city\":\"New York\"}";

        Gson gson = new Gson();
        MyObject myObject = gson.fromJson(json, MyObject.class);

        System.out.println("Name index: " + myObject.getNameIndex());
        System.out.println("Age index: " + myObject.getAgeIndex());
        System.out.println("City index: " + myObject.getCityIndex());
    }

    private static class MyObject {
        private String name;
        private int age;
        private String city;

        public String getNameIndex() {
            // 返回name字段在JSON对象中的索引
            return "0";
        }

        public String getAgeIndex() {
            // 返回age字段在JSON对象中的索引
            return "1";
        }

        public String getCityIndex() {
            // 返回city字段在JSON对象中的索引
            return "2";
        }
    }
}