对象序列化：pickle和shelve

import pickle
class DVD:
    def __init__(self,tilte,year=None,duration=None,director_id=None):
        self.title=tilte
        self.year=year
        self.duration=duration
        self.director_id=director_id
        self.filename=self.title.replace(',','_')+'.pickle'
    def save(self,filename=None):
        with open(self.filename,'wb')as fh:
            pickle.dump(self,fh)
    @staticmethod
    def load(filename):
        with open(filename,'rb')as fh:
            return pickle.load(fh)
    def __str__(self):
        return repr(self)
    def __repr__(self):
        return "DVD('{0}',{1},{2},'{3}')".format(self.title,self.year,self.duration,self.director_id)
dvd1=DVD('Birds',2016,1,'Justin Lin')
dvd1.save()
dvd2=DVD.load('Birds.pickle')
print(dvd2)