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。
如果你在通信的双方,你可以使用repr()和eval()函数和json。
import datetime, json
dt = datetime.datetime.now()
print("This is now: {}".format(dt))
dt1 = json.dumps(repr(dt))
print("This is serialised: {}".format(dt1))
dt2 = json.loads(dt1)
print("This is loaded back from json: {}".format(dt2))
dt3 = eval(dt2)
print("This is the same object as we started: {}".format(dt3))
print("Check if they are equal: {}".format(dt == dt3))
您不应该导入datetime as
from datetime import datetime
因为eval会报错。或者您可以将datetime作为参数传递给eval。在任何情况下,这都是可行的。
您必须使用json.dumps的cls参数提供一个自定义编码器类。引用文件中的内容:
>>> 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', ']']
这里使用了复数作为示例,但是您也可以轻松地创建一个类来编码日期(除了我认为JSON对于日期有点模糊)
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
我有一个类似问题的应用程序;我的方法是将datetime值JSONize为一个6项列表(年、月、日、小时、分钟、秒);你可以以微秒为单位列出7个项目,但我不需要这样做:
class DateTimeEncoder(json.JSONEncoder):
def default(self, obj):
if isinstance(obj, datetime.datetime):
encoded_object = list(obj.timetuple())[0:6]
else:
encoded_object =json.JSONEncoder.default(self, obj)
return encoded_object
sample = {}
sample['title'] = "String"
sample['somedate'] = datetime.datetime.now()
print sample
print json.dumps(sample, cls=DateTimeEncoder)
生产:
{'somedate': datetime.datetime(2013, 8, 1, 16, 22, 45, 890000), 'title': 'String'}
{"somedate": [2013, 8, 1, 16, 22, 45], "title": "String"}