fix bug: _id can't save to db
fix bug: _id can't save to db

alone-walker/BlogSpider,hack4code/BlogSpider,hack4code/BlogSpider,hack4code/BlogSpider,alone-walker/BlogSpider,wartalker/BlogSpider,wartalker/BlogSpider,wartalker/BlogSpider,hack4code/BlogSpider,wartalker/BlogSpider,alone-walker/BlogSpider,alone-walker/BlogSpider