利用python的pickle模块存储和读写任意的python数据结构

上文中提到PyQt的QDataStream类对Python类型和PyQt类型的数据进行读写操作，同样python自身提供了标准pickle模块可对任意的python数据结构进行存储和读写，当然pickle模块可以对Qt的数据类型进行存储和读写。其实QDataStream类和pickle模块大同小异的，但是在实践建议，当利用PyQt写Gui程序时，最好还是利用QDataStream类，因为它针对Qt类型更有效果。写标准的python程序，则利用pickle模块。
以下例子为创建一个类型结构Movie，包含的数据类型都是标准的python类型，然后将此类型通过pickle模块保存到二进制文件，然后从二进制文件将保存的内容读出。与上文提到的QDataStream类非常类似。

import pickle
import gzip
import os
import datetime

class Movie(object):
    UNKNOWNYEAR = 1890
    UNKNOWNMINUTES = 0
    def __init__(self, title=None, year=UNKNOWNYEAR,
                 minutes=UNKNOWNMINUTES, acquired=None, notes=None):
        self.title = title
        self.year = year
        self.minutes = minutes
        self.acquired = (acquired if acquired is not None
                                  else datetime.date.today())
        self.notes = notes
class MovieContainer(object):

    def __init__(self,fname,movies):
        self.__fname = fname
        self.__movies = movies        

    def savePickle(self):
        error = None
        fh = None
        try:
            fh = gzip.open(str(self.__fname), "wb")
            pickle.dump(self.__movies, fh, 2)
        except EnvironmentError as e:
            error = "Failed to save: {0}".format(e)
        finally:
            if fh is not None:
                fh.close()
            if error is not None:
                print(error)
            print("Saved 1 movie records to {0}".format(
                    os.path.basename(self.__fname)))


    def loadPickle(self):
        error = None
        fh = None
        try:
            fh = gzip.open(str(self.__fname), "rb")
            self.__movies = pickle.load(fh)
        except EnvironmentError as e:
            error = "Failed to load: {0}".format(e)
        finally:
            if fh is not None:
                fh.close()
            if error is not None:
                print(error)

            print("Loaded 1 movie records from {0}".format(
                    os.path.basename(self.__fname)) )   
            print(self.__movies.title,self.__movies.year,self.__movies.minutes,self.__movies.acquired,self.__movies.notes)  
if __name__ == "__main__":

    #textdata=[["god save",1989,45,None,"test data god save"],
              #["queen save",1960,56,None,"test data queen save"],
              #["HK save",1990,66,None,"test data HK save"],
              #["US save",2010,99,None,"test data US save"]]
    textdata=[["God save world",1989,45,None,"HELLO WORLD"]]
    fname="/home/yrd/work/movie.pickle"
    for data in textdata:
        movie=Movie(data[0],data[1],data[2],data[3],data[4])
        moviecontainer=MovieContainer(fname, movie)
        moviecontainer.savePickle()
        moviecontainer.loadPickle()

执行结果：
Saved 1 movie records to movie.pickle
Loaded 1 movie records from movie.pickle
God save world 1989 45 2017-01-14 HELLO WORLD