Python 对象序列化与反序列化之pickle json详细解析

# 序列化
In [19]: num = 66

In [20]: s = 'Python'

In [21]: pi = 3.14

In [22]: li = [1, 2, 3]

In [27]: b_num = pickle.dumps(num)

In [28]: b_s = pickle.dumps(s)

In [29]: b_pi = pickle.dumps(pi)

In [30]: b_li = pickle.dumps(li)

In [31]: b_num
Out[31]: b'\x80\x03KB.'

In [32]: b_s
Out[32]: b'\x80\x03X\x06\x00\x00\x00pythonq\x00.'

In [33]: b_pi
Out[33]: b'\x80\x03G@\t\x1e\xb8Q\xeb\x85\x1f.'

In [34]: b_li
Out[34]: b'\x80\x03]q\x00(K\x01K\x02K\x03e.'
    
In [35]: type(b_li)
Out[35]: bytes
    
# 反序列化    
In [47]: pickle.loads(b_num)
Out[47]: 66

In [48]: pickle.loads(b_s)
Out[48]: 'python'

In [49]: pickle.loads(b_pi)
Out[49]: 3.14

In [50]: li = pickle.loads(b_li)

In [51]: li
Out[51]: [1, 2, 3]

In [52]: type(li)
Out[52]: list    

class User:
    
    def __init__(self, name, sex):
        self.name = name
        self.sex = sex
        
In [38]: user = User('hui', '男')

In [39]: b_user = pickle.dumps(user)

In [40]: b_user
Out[40]: b'\x80\x03c__main__\nUser\nq\x00)\x81q\x01}q\x02(X\x04\x00\x00\x00nameq\x03X\x03\x00\x00\x00huiq\x04X\x03\x00\x00\x00sexq\x05X\x03\x00\x00\x00\xe7\x94\xb7q\x06ub.'

In [41]: type(b_user)
Out[41]: bytes

In [42]: user = pickle.loads(b_user)

In [43]: type(user)
Out[43]: __main__.User

In [44]: user.name
Out[44]: 'hui'

In [45]: user.sex
Out[45]: '男'        

import pickle

class User:
    
    def __init__(self, name, sex):
        self.name = name
        self.sex = sex
        
user = User('ithui', '男')
f = open('user.txt', mode='wb')
pickle.dump(user, f)
f.close()

In [3]: f = open('user.txt', 'rb')
   ...: user = pickle.load(f)
   ...: f.close()
   ...: 
In [4]: user
Out[4]: <__main__.User at 0x16c58ebef08>

In [5]: user.name
Out[5]: 'ithui'

In [6]: user.sex
Out[6]: '男'

In [7]: import json

In [8]: info_dict = {
   ...:     'name': 'hui',
   ...:     'age': 22,
   ...:     'is_admin': True,
   ...:     'hobbies': ['下象棋', '写代码'],
   ...:     'other': None
   ...: }

In [9]: info_json = json.dumps(info_dict)

In [10]: info_json
Out[10]: '{
    		"name": "hui", 
    		"age": 22, 
             "is_admin": true, 
             "hobbies": ["\\u4e0b\\u8c61\\u68cb", "\\u5199\\u4ee3\\u7801"], 
             "other": null
        }'
   
# 对应的反序列化
In [16]: info_d = json.loads(info_json)

In [17]: info_d
Out[17]:
{'name': 'hui',
 'age': 22,
 'is_admin': True,
 'hobbies': ['下象棋', '写代码'],
 'other': None}

In [18]: type(info_d)
Out[18]: dict        

In [21]: import json

In [22]: class User:
    ...:
    ...:     def __init__(self, name, sex):
    ...:         self.name = name
    ...:         self.sex = sex
    ...:

In [23]: user = User('ithui', '男')

In [24]: json.dumps(user)
    
TypeError: Object of type User is not JSON serializable    

In [28]: def user2dict(obj):
    ...:     return {'name': obj.name, 'sex': obj.sex}
    ...:
    ...:

In [29]: user = User('ithui', '男')

In [30]: user_dict = user2dict(user)

In [31]: user_dict
Out[31]: {'name': 'ithui', 'sex': '男'}

In [32]: user_json = json.dumps(user_dict)

In [33]: user_json
Out[33]: '{"name": "ithui", "sex": "\\u7537"}'

In [28]: def user2dict(obj):
    ...:     return {'name': obj.name, 'sex': obj.sex}
    ...:
    ...:
        
In [34]: user_json = json.dumps(user, default=user2dict)

In [35]: user_json
Out[35]: '{"name": "ithui", "sex": "\\u7537"}'

In [36]: user.__dict__
Out[36]: {'name': 'ithui', 'sex': '男'}
    
In [41]: json.dumps(user.__dict__)
Out[41]: '{"name": "ithui", "sex": "\\u7537"}'