如何在实体中为java Map接口创建json类型

import com.fasterxml.jackson.databind.ObjectMapper; // 导入Jackson库

public class Main {
    public static void main(String[] args) {
        // 创建一个Java Map对象
        Map<String, Object> map = new HashMap<>();
        map.put("name", "John");
        map.put("age", 30);
        map.put("city", "New York");

        // 将Map对象转换为JSON
        ObjectMapper objectMapper = new ObjectMapper();
        try {
            String json = objectMapper.writeValueAsString(map);
            System.out.println(json);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
    }
}