Object of type 'datetime' is not JSON serializable问题解决

1、现象

假设你的字典是样子的,你的value是一个datetime类型的值,这时候使用json.dump会报错 TypeError: Object of type 'datetime' is not JSON serializable

# encoding=utf-8
import datetime
import json

if __name__ == '__main__':
    data = {"id": 13500499, "update_time": datetime.datetime(2021, 12, 21, 6, 0, 15)}
    with open("测试.json", "w") as f:
        json.dump(data, f)

2、解决

①写个子类，继承json.JSONEncoder

②重写一下default函数

③json.dump时指定cls为子类

# encoding=utf-8
import datetime
import json

from datetime import date, datetime


class LoadDatetime(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, datetime):
            return obj.strftime('%Y-%m-%d %H:%M:%S')
        elif isinstance(obj, date):
            return obj.strftime('%Y-%m-%d')
        else:
            return json.JSONEncoder.default(self, obj)


if __name__ == '__main__':
    data = {"id": 13500499, "update_time": datetime(2021, 12, 21, 6, 0, 15)}
    with open("测试.json", "w") as f:
        json.dump(data, f, cls=LoadDatetime)

参考 https://blog.csdn.net/IT_xiao_bai/article/details/86686014