I have got the answer.
I edited the file bulkloader.py 2513line
original:
properties[name] = converter(val)
now:
if val=='None':
properties[name] = None
else:
properties[name] = converter(val)
On 5月10日, 上午10时59分, Mandla <[email protected]> wrote:
> Hi, all
> I have a java project on app engine, and I use python based code tobackupmy
> datastore.
>
> jdo
> class------------------------------------------------------------------------
> public class PaymentUser {
> @PrimaryKey
> private String transId;
> @Persistent
> private String media;
> @Persistent
> private float fee;
> @Persistent
> private String currency;
> @Persistent
> privatelongtimestamp;
>
> //getters and setter...
>
> }
>
> Thebackuppython
> code:---------------------------------------------------------
> from google.appengine.ext import db
> from google.appengine.tools import bulkloader
> import sys
> reload(sys)
> sys.setdefaultencoding('utf-8')
>
> class PaymentUser(db.Model):
> media = db.StringProperty()
> fee = db.FloatProperty()
> currency = db.StringProperty()
> timestamp = db.IntegerProperty()
>
> def AddKeys(entity_generator):
> for entity in entity_generator:
> entity['key'] = entity.key()
> yield entity
>
> class PaymentUserExporter(bulkloader.Exporter):
> def __init__(self):
> bulkloader.Exporter.__init__(self, 'PaymentUser',
>
> [('transId', str, None),
>
> ('media', str, None),
>
> ('fee', str, None),
>
> ('currency', str, None),
>
> ('timestamp', str, None)
> ])
> def output_entities(self, entity_generator):
> bulkloader.Exporter.output_entities(self,
> AddKeys(entity_generator))
> exporters = [PaymentUserExporter]
>
> class PaymentUserLoader(bulkloader.Loader):
> def __init__(self):
> bulkloader.Loader.__init__(self, 'PaymentUser',
>
> [('transId', str),
>
> ('media', str),
>
> ('fee', float),
>
> ('currency', str),
>
> ('timestamp', int)
> ])
> loaders = [PaymentUserLoader]
>
> And I use appcfg to backing up my data to CSV
> file.problems:--------------------------------------------------
> 1.The field currency either some String data or null (not take any
> space), because I have tobackupthese strings,so these nulls are.In
> my CSV file these nulls are str "None". When I upload these data to
> server again,I found original nulls are replaced by string None.Here I
> will waste many spaces.
> 2. The problem is as same as the first one. But is along
> property(timestamp), when I upload the data to server These None
> connot be converted tolongvalue, so there are many exceptions.
>
> How can I solve it, Thanks.
>
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