我正在使用dataclasses+dataclasses_json来实现我的Web API。
我的应用程序将解码从dict到对象的请求，我希望在不填充每个字段的情况下仍可以生成对象，并使用默认值填充空文件。
这是我可能的代码：
from dataclasses import dataclass
from dataclasses_json import dataclass_json
@dataclass
class Glasses:
color: str
size: str
prize: int
@dataclass
class Tshirt:
color: str
size: str
prize: int
@dataclass_json
@dataclass
class People:
Name : str = 'James'
Age : int = 25
Glasses: Glasses = Glasses('black', 'M', 2500)
Tshirt: Tshirt = Tshirt('black', 'XL', 500)
p = {
'Name': 'Gino',
'Age': 20,
'Glasses': {
'color' : 'red',
'size' : 'M',
'prize' : 4000
},
'Tshirt': {
'color' : 'red',
'size' : 'M',
'prize' : 4000
}
}
a = People.from_dict(p)
print(a)
我会得到错误
Traceback (most recent call last):
File ".\People.py", line 39, in <module>
a = People.from_dict(p)
File "C:\Python3.7\lib\site-packages\dataclasses_json\api.py", line 83, in from_dict
return _decode_dataclass(cls, kvs, infer_missing)
File "C:\Python3.7\lib\site-packages\dataclasses_json\core.py", line 133, in _decode_dataclass
overrides = _user_overrides_or_exts(cls)
File "C:\Python3.7\lib\site-packages\dataclasses_json\core.py", line 59, in _user_overrides_or_exts
if field.type in encoders:
TypeError: unhashable type: 'Glasses'
我发现我可以添加（eq = True，Frozen = True）所以我将代码更改为
from dataclasses import dataclass
from dataclasses_json import dataclass_json
@dataclass(eq=True, frozen=True)
class Glasses:
color: str
size: str
prize: int
@dataclass(eq=True, frozen=True)
class Tshirt:
color: str
size: str
prize: int
@dataclass_json
@dataclass
class People:
Name : str = 'James'
Age : int = 25
Glasses: Glasses = Glasses('black', 'M', 2500)
Tshirt: Tshirt = Tshirt('black', 'XL', 500)
p = {
'Name': 'Gino',
'Age': 20,
'Glasses': {
'color' : 'red',
'size' : 'M',
'prize' : 4000
},
'Tshirt': {
'color' : 'red',
'size' : 'M',
'prize' : 4000
}
}
a = People.from_dict(p)
print(a)
我得到另一个错误
File ".\People.py", line 39, in <module>
a = People.from_dict(p)
File "C:\Python3.7\lib\site-packages\dataclasses_json\api.py", line 83, in from_dict
return _decode_dataclass(cls, kvs, infer_missing)
File "C:\Python3.7\lib\site-packages\dataclasses_json\core.py", line 198, in _decode_dataclass
infer_missing)
File "C:\Python3.7\lib\site-packages\dataclasses_json\core.py", line 131, in _decode_dataclass
if isinstance(kvs, cls):
TypeError: isinstance() arg 2 must be a type or tuple of types
有什么可能的方法可以使用内置函数来满足我的要求，而无需自己编写代码？
您有字段名称和类型名称冲突。为了使您的代码正常工作，您必须具有与类名称不同的JSON字段名称，即您不能具有field"Glasses"和class Glasses，您必须将class重命名为likeGlasses_或重命名字段名称。
另一种选择是对类类型创建别名，即创建别名GlassesT来Glasses。
带有类型别名的代码版本：
from dataclasses import dataclass
from dataclasses_json import dataclass_json
@dataclass
class Glasses:
color: str
size: str
prize: int
GlassesT = Glasses
@dataclass
class Tshirt:
color: str
size: str
prize: int
TshirtT = Tshirt
@dataclass_json
@dataclass
class People:
Name : str = 'James'
Age : int = 25
Glasses: GlassesT = GlassesT('black', 'M', 2500)
Tshirt: TshirtT = TshirtT('black', 'XL', 500)
p = {
'Name': 'Gino',
'Age': 20,
'Glasses': {
'color' : 'red',
'size' : 'M',
'prize' : 4000
},
'Tshirt': {
'color' : 'red',
'size' : 'M',
'prize' : 4000
}
}
a = People.from_dict(p)
print(a)
输出：
People(Name='Gino', Age=20, Glasses=Glasses(color='red', size='M', prize=4000), Tshirt=Tshirt(color='red', size='M', prize=4000))
带有重命名类的代码版本：
from dataclasses import dataclass
from dataclasses_json import dataclass_json
@dataclass
class Glasses_:
color: str
size: str
prize: int
@dataclass
class Tshirt_:
color: str
size: str
prize: int
@dataclass_json
@dataclass
class People:
Name : str = 'James'
Age : int = 25
Glasses: Glasses_ = Glasses_('black', 'M', 2500)
Tshirt: Tshirt_ = Tshirt_('black', 'XL', 500)
p = {
'Name': 'Gino',
'Age': 20,
'Glasses': {
'color' : 'red',
'size' : 'M',
'prize' : 4000
},
'Tshirt': {
'color' : 'red',
'size' : 'M',
'prize' : 4000
}
}
a = People.from_dict(p)
print(a)
输出：
People(Name='Gino', Age=20, Glasses=Glasses_(color='red', size='M', prize=4000), Tshirt=Tshirt_(color='red', size='M', prize=4000))
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