如何将JSON转换为自定义类的实例？

Question

我不确定以前是否有人问过这个问题，但我找不到相关的自定义映射。通常，它是直接的JSON到对象的1:1映射。

下面是我的示例：

class Test():
    id: str
    name: str
    msg: str

data = [
    {
        "id": "12345",
        "client": "test",
        "msg": "random"
    }, {
        "id": "54321",
        "client": "test-2",
        "msg": "random-2"
    }
]

所以在上面我有一个JSON，我想直接将它转换成我在第一个类上拥有的对象。注意，来自JSON的“客户端”变成了name。

所以当我加载这个对象的时候，最终的输出是。

data = [
    {
        "id": "12345",
        "name": "test",
        "msg": "random"
    }, {
        "id": "54321",
        "name": "test-2",
        "msg": "random-2"
    }
]

Answer 1

class Test():
    def __init__(self, id, client, msg):
        self.id = id
        self.name = client
        self.msg = msg

data = [
    {
        "id": "12345",
        "client": "test",
        "msg": "random"
    }, {
        "id": "54321",
        "client": "test-2",
        "msg": "random-2"
    }
]

# unpack values from dict and pass in as arguments for Test.__init__()
objects = [Test(**item) for item in data] 

Answer 2

您也可以使用Pydantic来定义您的类，如下所示：

from pydantic import BaseModel

class User(BaseModel):
    id: str
    name: str
    msg: str

    def __init__(self, id: str, client: str, msg: str) -> None:
        super().__init__(id=id, name=client, msg=msg)

users = [
    {
        'id': '12345',
        'client': 'test',
        'msg': 'random',
    },
    {
        'id': '54321',
        'client': 'test-2',
        'msg': 'random-2',
    }
]

objects = [User(**user) for user in users]

print(objects)
# Output
[
   User(id='12345', name='test', msg='random'),
   User(id='54321', name='test-2', msg='random-2')
]