Question

编辑：使用

添加新输出

logging.info(id(type(Decimal(10))))
logging.info(id(type(obj)))

我正在尝试转储到JSON。我知道我需要将Decimal转换为float，所以这是我的代码：

def get(self):
    results = CheckPulseRequest.get(get_args(self.request))
    self.response.headers['Content-Type'] = 'application/json'
    self.response.out.write(json.dumps(results, cls=DateTimeEncoder))

然后我按如下方式定义了DateTimeEncoder：

class DateTimeEncoder(json.JSONEncoder):
    logging.info("In DateTimeEncoder Class")

    def default(self, obj):
        logging.info(id(type(Decimal(10))))
        logging.info(id(type(obj)))
        logging.info(type(Decimal(10)))
        logging.info(type(obj))
        logging.info(isinstance(Decimal(10), (int, long, float, complex, Decimal)))
        logging.info(isinstance(obj, (int, long, float, complex, Decimal)))

        if isinstance(obj, Decimal):
            logging.info("Is Instance of Decimal")
            return float(obj)
        elif hasattr(obj, 'isoformat'):
            logging.info("Is ISO Format")
            return obj.isoformat()
        else:
            logging.info("Else")
            return json.JSONEncoder.default(self, obj)

我得到以下日志输出。我的十进制对象不会转换为浮点数。请注意，该对象与Decimal具有相同的类型，但isinstance测试仅在Decimal（10）测试中为True。我错过了什么？

INFO     2015-02-23 18:49:45,737 check_pulse_request.py:25] Getting Check Pulse Request ID: 4
INFO     2015-02-23 18:49:46,374 main.py:179] 140647859901984
INFO     2015-02-23 18:49:46,375 main.py:180] 140647856664608
INFO     2015-02-23 18:49:46,375 main.py:181] <class 'decimal.Decimal'>
INFO     2015-02-23 18:49:46,375 main.py:182] <class 'decimal.Decimal'>
INFO     2015-02-23 18:49:46,375 main.py:183] True
INFO     2015-02-23 18:49:46,375 main.py:184] False
INFO     2015-02-23 18:49:46,376 main.py:193] Else
ERROR    2015-02-23 18:49:46,376 webapp2.py:1552] Decimal('-122.39906660000000') is not JSON serializable
Traceback (most recent call last):
  File "/Users/sheridangray/Projects/adt-bundle-mac-x86_64-20140702/sdk/google-cloud-sdk/platform/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1535, in __call__
    rv = self.handle_exception(request, response, e)
  File "/Users/sheridangray/Projects/adt-bundle-mac-x86_64-20140702/sdk/google-cloud-sdk/platform/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1529, in __call__
    rv = self.router.dispatch(request, response)
  File "/Users/sheridangray/Projects/adt-bundle-mac-x86_64-20140702/sdk/google-cloud-sdk/platform/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1278, in default_dispatcher
    return route.handler_adapter(request, response)
  File "/Users/sheridangray/Projects/adt-bundle-mac-x86_64-20140702/sdk/google-cloud-sdk/platform/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1102, in __call__
    return handler.dispatch()
  File "/Users/sheridangray/Projects/adt-bundle-mac-x86_64-20140702/sdk/google-cloud-sdk/platform/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 572, in dispatch
    return self.handle_exception(e, self.app.debug)
  File "/Users/sheridangray/Projects/adt-bundle-mac-x86_64-20140702/sdk/google-cloud-sdk/platform/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 570, in dispatch
    return method(*args, **kwargs)
  File "/Users/sheridangray/Projects/city-pulse-appengine/city-pulse/main.py", line 38, in get
    self.response.out.write(json.dumps(results, cls=DateTimeEncoder))
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 250, in dumps
    sort_keys=sort_keys, **kw).encode(obj)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 207, 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 270, in iterencode
    return _iterencode(o, 0)
  File "/Users/sheridangray/Projects/city-pulse-appengine/city-pulse/main.py", line 194, in default
    return json.JSONEncoder.default(self, obj)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 184, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: Decimal('-122.39906660000000') is not JSON serializable

Answer 1

我真的没有＃34;修复＆＃34;问题，但通过将我的MySQL数据库列更改为FLOAT来解决它。

JSON转储Decimal不可序列化

1 个答案: