将Python数据类优雅地转换为JSON的方法详解

from dataclasses import dataclass

@dataclass
class User:
    name: str
    age: int
    email: str

import json

def dataclass_to_dict(instance):
    return {field.name: getattr(instance, field.name) for field in instance.__dataclass_fields__.values()}

user = User(name='Alice', age=30, email='alice@example.com')
user_dict = dataclass_to_dict(user)
user_json = json.dumps(user_dict)

print(user_json)

{"name": "Alice", "age": 30, "email": "alice@example.com"}

from datetime import datetime
from typing import List

@dataclass
class Post:
    title: str
    content: str
    published_date: datetime

@dataclass
class User:
    name: str
    age: int
    email: str
    posts: List[Post]

def dataclass_to_dict(instance):
    if hasattr(instance, '__dataclass_fields__'):
        return {
            field.name: dataclass_to_dict(getattr(instance, field.name))
            for field in instance.__dataclass_fields__.values()
        }
    elif isinstance(instance, list):
        return [dataclass_to_dict(item) for item in instance]
    elif isinstance(instance, datetime):
        return instance.isoformat()  # 处理日期类型
    return instance  # 原样返回其他数据类型

user = User(
    name='Alice',
    age=30,
    email='alice@example.com',
    posts=[
        Post(title='My first post', content='This is the content.', published_date=datetime.now()),
        Post(title='Another post', content='More content here.', published_date=datetime.now())
    ]
)

user_dict = dataclass_to_dict(user)
user_json = json.dumps(user_dict)

print(user_json)

from dataclasses import dataclass
from dataclasses_json import dataclass_json

@dataclass_json
@dataclass
class User:
    name: str
    age: int
    email: str