json，json扩展

#参数1：obj(基本数据类型) 参数2：fp=open(file)
def dump(obj, fp, *, 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`` as a JSON formatted stream to ``fp`` (a ???``.write()``-supporting file-like object). ????#具备f.write()的功能 ???If ``skipkeys`` is true then ``dict`` keys that are not basic types ???(``str``, ``int``, ``float``, ``bool``, ``None``) will be skipped ???instead of raising a ``TypeError``. ???If ``ensure_ascii`` is false, then the strings written to ``fp`` can ???contain non-ASCII characters if they appear in strings contained in ???``obj``. Otherwise, all such characters are escaped in JSON strings. ???If ``check_circular`` is false, then the circular reference check ???for container types will be skipped and a circular reference will ???result in an ``OverflowError`` (or worse). ???If ``allow_nan`` is false, then it will be a ``ValueError`` to ???serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) ???in strict compliance of the JSON specification, instead of using the ???JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). ???If ``indent`` is a non-negative integer, then JSON array elements and ???object members will be pretty-printed with that indent level. An indent ???level of 0 will only insert newlines. ``None`` is the most compact ???representation. ???If specified, ``separators`` should be an ``(item_separator, key_separator)`` ???tuple. ?The default is ``(‘, ‘, ‘: ‘)`` if *indent* is ``None`` and ???``(‘,‘, ‘: ‘)`` otherwise. ?To get the most compact JSON representation, ???you should specify ``(‘,‘, ‘:‘)`` to eliminate whitespace. ???``default(obj)`` is a function that should return a serializable version ???of obj or raise TypeError. The default simply raises TypeError. ???If *sort_keys* is true (default: ``False``), then the output of ???dictionaries will be sorted by key. ???To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the ???``.default()`` method to serialize additional types), specify it with ???the ``cls`` kwarg; otherwise ``JSONEncoder`` is used. ???""" ???# cached encoder ???if (not skipkeys and ensure_ascii and ???????check_circular and allow_nan and ???????cls is None and indent is None and separators is None and ???????default is None and not sort_keys and not kw): ???????iterable = _default_encoder.iterencode(obj) ???else: ???????if cls is None: ???????????cls = JSONEncoder ???????iterable = cls(skipkeys=skipkeys, ensure_ascii=ensure_ascii, ???????????check_circular=check_circular, allow_nan=allow_nan, indent=indent, ???????????separators=separators, ???????????default=default, sort_keys=sort_keys, **kw).iterencode(obj) ???# could accelerate with writelines in some versions of Python, at ???# a debuggability cost ???for chunk in iterable: ???????fp.write(chunk)

class JSONEncoder(object):
#默认json只能序列化基本数据类型 ???"""Extensible JSON <http://json.org> encoder for Python data structures. ???Supports the following objects and types by default: ???+-------------------+---------------+ ???| Python ???????????| JSON ?????????| ???+===================+===============+ ???| dict ?????????????| object ???????| ???+-------------------+---------------+ ???| list, tuple ??????| array ????????| ???+-------------------+---------------+ ???| str ??????????????| string ???????| ???+-------------------+---------------+ ???| int, float ???????| number ???????| ???+-------------------+---------------+ ???| True ?????????????| true ?????????| ???+-------------------+---------------+ ???| False ????????????| false ????????| ???+-------------------+---------------+ ???| None ?????????????| null ?????????| ???+-------------------+---------------+ ???To extend this to recognize other objects, subclass and implement a ???``.default()`` method with another method that returns a serializable ???object for ``o`` if possible, otherwise it should call the superclass ???implementation (to raise ``TypeError``). ???"""

def default(self, o): ??????????????????#默认会报错
 ???"""Implement this method in a subclass such that it returns
 ???a serializable object for ``o``, or calls the base implementation
 ???(to raise a ``TypeError``).

 ???For example, to support arbitrary iterators, you could
 ???implement default like this::

 ???????def default(self, o):
 ???????????try:
 ???????????????iterable = iter(o)
 ???????????except TypeError:
 ???????????????pass
 ???????????else:
 ???????????????return list(iterable)
 ???????????# Let the base class default method raise the TypeError
 ???????????return JSONEncoder.default(self, o)

 ???"""
 ???raise TypeError("Object of type ‘%s‘ is not JSON serializable" %
 ???????????????????o.__class__.__name__)

import json as default_json ????????????from json.encoder import JSONEncoderfrom .response import BaseResponseclass JsonEncoder(JSONEncoder): ??#继承JSONEncoder ???def default(self, o): ?????????????????#写default 方法 ???????if isinstance(o,BaseResponse): ???????????return o.__dict__ ???????return JSONEncoder.default(self,o)class Json(object): ????????????#自定义的Json ???@staticmethod ???def dumps(response,ensure_ascii=True): ??????#自定义的dumps ???????return default_json.dumps(response,ensure_ascii=ensure_ascii,cls=JsonEncoder) ???
#自定义的dumps返回系统(json)的dumps方法，但是cls是扩展的JsonEncoder

To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the
``.default()`` method to serialize additional types), specify it with
the ``cls`` kwarg; otherwise ``JSONEncoder`` is used.

"""