如何在java中解析json对象内部的json对象

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.12.5</version>
</dependency>

{
  "name": "John",
  "age": 30,
  "address": {
    "city": "New York",
    "country": "USA"
  }
}

public class Person {
    private String name;
    private int age;
    private Address address;

    // Getters and setters
}

public class Address {
    private String city;
    private String country;

    // Getters and setters
}

import com.fasterxml.jackson.databind.ObjectMapper;

public class Main {
    public static void main(String[] args) throws Exception {
        String json = "{\"name\":\"John\",\"age\":30,\"address\":{\"city\":\"New York\",\"country\":\"USA\"}}";

        ObjectMapper objectMapper = new ObjectMapper();
        Person person = objectMapper.readValue(json, Person.class);

        System.out.println("Name: " + person.getName());
        System.out.println("Age: " + person.getAge());
        System.out.println("City: " + person.getAddress().getCity());
        System.out.println("Country: " + person.getAddress().getCountry());
    }
}

Name: John
Age: 30
City: New York
Country: USA

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.8</version>
</dependency>

import com.google.gson.Gson;

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

        Gson gson = new Gson();
        Person person = gson.fromJson(json, Person.class);

        System.out.println("Name: " + person.getName());
        System.out.println("Age: " + person.getAge());
        System.out.println("City: " + person.getAddress().getCity());
        System.out.println("Country: " + person.getAddress().getCountry());
    }
}

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.78</version>
</dependency>

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

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

        JSONObject jsonObject = JSON.parseObject(json);
        String name = jsonObject.getString("name");
        int age = jsonObject.getIntValue("age");
        JSONObject addressObject = jsonObject.getJSONObject("address");
        String city = addressObject.getString("city");
        String country = addressObject.getString("country");

        System.out.println("Name: " + name);
        System.out.println("Age: " + age);
        System.out.println("City: " + city);
        System.out.println("Country: " + country);
    }
}