Python | JSON(Dict)与Class转换

1. 前言

$JSON\iff Dict\iff Class$

这里主要讲的是Dict与Class转换，至于Dict与JSON字符串之前转换可以直接使用系统方法，如下

import json

d = {'name': 'yimt', 'age': 123, 'detail': {'phone': '123456789'}}

# Dict->JSON Str
s: str = json.dumps(d)

# JSON Str->Dict
d = json.loads(s)

2. 使用内置方法

Dict嵌套时会出现不符合预期的情况。

class Detail:
    phone: str

    def __str__(self):
        return f'phone={self.phone}'


class Person:
    name: str
    age: int
    detail: Detail

    def __str__(self):
        return f'name={self.name}, age={self.age}, detail=Detail({self.detail})'


if __name__ == '__main__':
    d = {'name': 'yimt', 'age': 123, 'detail': {'phone': '123456789'}}
    p: Person = Person()

    # Dict -> Class
    p.__dict__ = d
    print(p)  # Output: name=yimt, age=123, detail=Detail({'phone': '123456789'})

    # Class -> Dict
    print(p.__dict__)  # Output: {'name': 'yimt', 'age': 123, 'detail': {'phone': '123456789'}}

3. pydantic

嵌套的Dict转Class，Class转Dict

from pydantic import BaseModel


class Detail(BaseModel):
    phone: str

    def __str__(self):
        return f'phone={self.phone}'


class Person(BaseModel):
    name: str
    age: int
    detail: Detail

    def __str__(self):
        return f'name={self.name}, age={self.age}, detail=Detail({self.detail})'


if __name__ == '__main__':
    d = {'name': 'yimt', 'age': 123, 'detail': {'phone': '123456789'}}

    # Dict -> Class
    p: Person = Person(**d)
    print(p)  # name=yimt, age=123, detail=Detail(phone=123456789)

    # Class -> Dict
    print(p.json())  # Output: {"name": "yimt", "age": 123, "detail": {"phone": "123456789"}}