JSON解析遇到的字段名转换问题

一、问题背景

在使用JSON对Object进行解析后得到的是一个K-V键值对，但是原始的Object字段名可能为驼峰命名或下划线或帕斯卡等各种各样的方式，那么在进行JSON解析之后得到的\(key\)名字就会不同。如何解决这个问题？现考虑代码中使用了fastjson或jackson的解析方法进行转换。

二、测试

1、实体测试类：

再搞个复杂点的DTO类：

2、封装fastjson和jackson两个工具类：

package com.maverick.util;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.PropertyNamingStrategy;
import com.alibaba.fastjson.serializer.SerializeConfig;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JsonUtils {
    private final static SerializeConfig FAST_JSON_CONFIG = new SerializeConfig();
    static {
        FAST_JSON_CONFIG.propertyNamingStrategy = PropertyNamingStrategy.SnakeCase;
    }

    private final static ObjectMapper OBJECT_MAPPER = new ObjectMapper();
    static {
        OBJECT_MAPPER.setPropertyNamingStrategy(com.fasterxml.jackson.databind.PropertyNamingStrategy.SNAKE_CASE);
    }

    private JsonUtils() {
    }

    /**
     * 使用fastjson
     *
     * @param object
     * @return
     */
    public static String getFromFastJson(Object object) {
        try {
            return JSON.toJSONString(object, FAST_JSON_CONFIG);
        } catch (Exception e) {
            throw new RuntimeException(e.toString());
        }
    }

    /**
     * 使用jackson
     * 
     * @param object
     * @return
     */
    public static String getFromJackson(Object object) {
        try {
            return OBJECT_MAPPER.writeValueAsString(object);
        } catch (JsonProcessingException e) {
            throw new RuntimeException(e.toString());
        }
    }
}

3、测试程序：

public class Demo {
    public static void main(String[] args) {
        User user = new User("张三", 20, "101101");
        Phone phone = new Phone('1', "1234455767");
        List<CustDTO> list = new ArrayList<>();
        CustDTO custDTO = new CustDTO();
        custDTO.setUser(new User("李四", 30, "101101"));
        custDTO.setPhone(new Phone('0', "057105710571"));
        list.add(custDTO);

        Map<String, Object> map = new HashMap<>();
        map.put("user", user);
        map.put("phone", phone);
        map.put("custdto", custDTO);

        // 实际项目中不要使用这种方式, 尽量使用单例模式
//        SerializeConfig config = new SerializeConfig();
//        config.propertyNamingStrategy = PropertyNamingStrategy.SnakeCase;

        String json_1 = JsonUtils.getFromFastJson(map);
        System.out.println(json_1);

        String json_2 = JsonUtils.getFromJackson(map);
        System.out.println(json_2);

        System.out.println(json_1.equals(json_2));

    }
}

测试结果如下，可以看到解析后驼峰字段都转为了下划线的方式（如tel_kind、tel_no）

fastjson: {"phone":{"tel_kind":"1","tel_no":"1234455767"},"custdto":{"phone":{"tel_kind":"0","tel_no":"057105710571"},"user":{"age":30,"name":"李四","zipcode":"101101"}},"user":{"age":20,"name":"张三","zipcode":"101101"}}
jackson: {"phone":{"tel_kind":"1","tel_no":"1234455767"},"custdto":{"phone":{"tel_kind":"0","tel_no":"057105710571"},"user":{"name":"李四","age":30,"zipcode":"101101"}},"user":{"name":"张三","age":20,"zipcode":"101101"}}