我有一个基本的字典如下:

sample = {}
sample['title'] = "String"
sample['somedate'] = somedatetimehere

当我尝试做jsonify(sample)时,我得到:

TypeError: datetime.datetime(2012, 8, 8, 21, 46, 24, 862000) is not JSON serializable

我该怎么做才能使我的字典样本克服上面的错误呢?

注意:虽然它可能不相关,字典是从mongodb的记录检索中生成的,当我打印出str(sample['somedate'])时,输出是2012-08-08 21:46:24.862000。


当前回答

我可能不是百分百正确, 这是实现序列化的简单方法

#!/usr/bin/python
import datetime,json

sampledict = {}
sampledict['a'] = "some string"
sampledict['b'] = datetime.datetime.now()

print sampledict   # output : {'a': 'some string', 'b': datetime.datetime(2017, 4, 15, 5, 15, 34, 652996)}

#print json.dumps(sampledict)

'''
output : 

Traceback (most recent call last):
  File "./jsonencodedecode.py", line 10, in <module>
    print json.dumps(sampledict)
  File "/usr/lib/python2.7/json/__init__.py", line 244, in dumps
    return _default_encoder.encode(obj)
  File "/usr/lib/python2.7/json/encoder.py", line 207, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python2.7/json/encoder.py", line 270, in iterencode
    return _iterencode(o, 0)
  File "/usr/lib/python2.7/json/encoder.py", line 184, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: datetime.datetime(2017, 4, 15, 5, 16, 17, 435706) is not JSON serializable


'''

sampledict['b'] = datetime.datetime.now().strftime("%B %d, %Y %H:%M %p")

afterdump = json.dumps(sampledict)

print afterdump  #output : {"a": "some string", "b": "April 15, 2017 05:18 AM"}

print type(afterdump) #<type 'str'>


afterloads = json.loads(afterdump) 

print afterloads # output : {u'a': u'some string', u'b': u'April 15, 2017 05:18 AM'}


print type(afterloads) # output :<type 'dict'> 

其他回答

我的快速和肮脏的JSON转储吃日期和一切:

json.dumps(my_dictionary, indent=4, sort_keys=True, default=str)

Default是一个应用于不可序列化对象的函数。 在这种情况下,它是str,所以它只是把所有它不知道的东西转换成字符串。这对于序列化很好,但在反序列化时就不太好了(因此是“快速和肮脏”),因为任何东西都可能在没有警告的情况下被字符串化,例如函数或numpy数组。

我在外部化django模型对象转储为JSON时也遇到了同样的问题。 以下是解决方法。

def externalize(model_obj):
  keys = model_obj._meta.get_all_field_names() 
  data = {}
  for key in keys:
    if key == 'date_time':
      date_time_obj = getattr(model_obj, key)
      data[key] = date_time_obj.strftime("%A %d. %B %Y")
    else:
      data[key] = getattr(model_obj, key)
  return data

我可能不是百分百正确, 这是实现序列化的简单方法

#!/usr/bin/python
import datetime,json

sampledict = {}
sampledict['a'] = "some string"
sampledict['b'] = datetime.datetime.now()

print sampledict   # output : {'a': 'some string', 'b': datetime.datetime(2017, 4, 15, 5, 15, 34, 652996)}

#print json.dumps(sampledict)

'''
output : 

Traceback (most recent call last):
  File "./jsonencodedecode.py", line 10, in <module>
    print json.dumps(sampledict)
  File "/usr/lib/python2.7/json/__init__.py", line 244, in dumps
    return _default_encoder.encode(obj)
  File "/usr/lib/python2.7/json/encoder.py", line 207, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python2.7/json/encoder.py", line 270, in iterencode
    return _iterencode(o, 0)
  File "/usr/lib/python2.7/json/encoder.py", line 184, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: datetime.datetime(2017, 4, 15, 5, 16, 17, 435706) is not JSON serializable


'''

sampledict['b'] = datetime.datetime.now().strftime("%B %d, %Y %H:%M %p")

afterdump = json.dumps(sampledict)

print afterdump  #output : {"a": "some string", "b": "April 15, 2017 05:18 AM"}

print type(afterdump) #<type 'str'>


afterloads = json.loads(afterdump) 

print afterloads # output : {u'a': u'some string', u'b': u'April 15, 2017 05:18 AM'}


print type(afterloads) # output :<type 'dict'> 

其实很简单。 如果您需要经常序列化日期,那么可以将它们作为字符串使用。如果需要,您可以轻松地将它们转换回datetime对象。

如果您主要需要作为datetime对象工作,那么在序列化之前将它们转换为字符串。

import json, datetime

date = str(datetime.datetime.now())
print(json.dumps(date))
"2018-12-01 15:44:34.409085"
print(type(date))
<class 'str'>

datetime_obj = datetime.datetime.strptime(date, '%Y-%m-%d %H:%M:%S.%f')
print(datetime_obj)
2018-12-01 15:44:34.409085
print(type(datetime_obj))
<class 'datetime.datetime'>

如您所见,两种情况下的输出是相同的。只是类型不同。

我的解决方案是……

from datetime import datetime
import json

from pytz import timezone
import pytz


def json_dt_serializer(obj):
    """JSON serializer, by macm.
    """
    rsp = dict()
    if isinstance(obj, datetime):
        rsp['day'] = obj.day
        rsp['hour'] = obj.hour
        rsp['microsecond'] = obj.microsecond
        rsp['minute'] = obj.minute
        rsp['month'] = obj.month
        rsp['second'] = obj.second
        rsp['year'] = obj.year
        rsp['tzinfo'] = str(obj.tzinfo)
        return rsp
    raise TypeError("Type not serializable")


def json_dt_deserialize(obj):
    """JSON deserialize from json_dt_serializer, by macm.
    """
    if isinstance(obj, str):
        obj = json.loads(obj)
    tzone = timezone(obj['tzinfo'])
    tmp_dt = datetime(obj['year'],
                      obj['month'],
                      obj['day'],
                      hour=obj['hour'],
                      minute=obj['minute'],
                      second=obj['second'],
                      microsecond=obj['microsecond'])
    loc_dt = tzone.localize(tmp_dt)
    deserialize = loc_dt.astimezone(tzone)
    return deserialize    

好,现在来做一些测试。

# Tests
now = datetime.now(pytz.utc)

# Using this solution
rsp = json_dt_serializer(now)
tmp = json_dt_deserialize(rsp)
assert tmp == now
assert isinstance(tmp, datetime) == True
assert isinstance(now, datetime) == True

# using default from json.dumps
tmp = json.dumps(datetime.now(pytz.utc), default=json_dt_serializer)
rsp = json_dt_deserialize(tmp)
assert isinstance(rsp, datetime) == True

# Lets try another timezone
eastern = timezone('US/Eastern')
now = datetime.now(eastern)
rsp = json_dt_serializer(now)
tmp = json_dt_deserialize(rsp)

print(tmp)
# 2015-10-22 09:18:33.169302-04:00

print(now)
# 2015-10-22 09:18:33.169302-04:00

# Wow, Works!
assert tmp == now