对象转 dict

import json
class A:
    a = 1
class B:
    b = 2
class Test:
    a = A()
    b = B()
def to_dict(obj):
    d = {}
    for name in dir(obj):
        value = getattr(obj, name)
        if not name.startswidth("__") and not callable(value):
            d[name] = value
    return d
test = Test()
json.loads(json.dumps(test, default=to_dict))