Python 类对象的JSON序列化与反序列化

1. Python 类对象

class Token:
  def __init__(self, name, address, symbol, decimals):
    self.name = name
    self.address = address
    self.symbol = symbol
    self.decimals = decimals

2. JSON 序列化Token对象

import json

token = Token('Tether USD', '0xdac17f958d2ee523a2206206994597c13d831ec7', 'USDT', 6)
json.dumps(token)
# TypeError: Object of type Token is not JSON serializable

3. JSON.dumps 定义

dumps(obj, *, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, cls=None, indent=None, separators=None, default=None, sort_keys=False, **kw)
    Serialize ``obj`` to a JSON formatted ``str``.
...
``default(obj)`` is a function that should return a serializable version of obj or raise TypeError. The default simply raises TypeError.
# 可参数default用于把任意一个对象变成一个可序列为JSON的对象
....

4. JSON 序列化类对象

json.dumps(u, default=lambda obj: obj.__dict__, sort_keys=True)
# output:
# '{"address": "0xdAC17F958D2ee523a2206206994597C13D831ec7", "decimals": 6, "name": "Tether USD", "symbol": "USDT"}'

5. JSON.loads定义

loads(s, *, cls=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, object_pairs_hook=None, **kw)
    Deserialize ``s`` (a ``str``, ``bytes`` or ``bytearray`` instance containing a JSON document) to a Python object
``object_hook`` is an optional function that will be called with the result of any object literal decode (a ``dict``). The return value of
    ``object_hook`` will be used instead of the ``dict``. This feature can be used to implement custom decoders (e.g. JSON-RPC class hinting).
...

6. JSON反序列为类对象

def handle(t):
  return Token(t['name'], t['address'], t['symbol'], t['decimals'])

json_str = '{"address": "0xdAC17F958D2ee523a2206206994597C13D831ec7", "decimals": 6, "name": "Tether USD", "symbol": "USDT"}'
token = json.loads(json_str, object_hook=handle)

7. 参考

• Python类对象的JSON序列化处理