如何在python中json序列化对象

Question

Does python support random json serialization? I get this error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "commands.py", line 36, in toJson
    return json.dumps(self)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 201, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 264, in iterencode
    return _iterencode(o, 0)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 178, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: <commands.SampleCommand object at 0x105d957d0> is not JSON serializable

Snippet:

class SampleCommand(Command):
    def __init__(self,message=None):
        super(Command, self).__init__()
        pass

    def parse(self):
        pass

    def toJson(self):
        return json.dumps(self)

Answer 1

json within python by default can only handle certain objects like dictionaries, list and basic types such as ints, strings and so on for more complex types you need to define your own serialization scheme

>>> help(json)
Extending JSONEncoder::

    >>> import json
    >>> class ComplexEncoder(json.JSONEncoder):
    ...     def default(self, obj):
    ...         if isinstance(obj, complex):
    ...             return [obj.real, obj.imag]
    ...         return json.JSONEncoder.default(self, obj)
    ...
    >>> dumps(2 + 1j, cls=ComplexEncoder)
    '[2.0, 1.0]'
    >>> ComplexEncoder().encode(2 + 1j)
    '[2.0, 1.0]'
    >>> list(ComplexEncoder().iterencode(2 + 1j))
    ['[', '2.0', ', ', '1.0', ']']