day21作业

1、定义MySQL类

1.对象有id、host、port三个属性
2.定义工具create_id，在实例化时为每个对象随机生成id，保证id唯一
3.提供两种实例化方式，方式一：用户传入host和port 方式二：从配置文件中读取host和port进行实例化
4.为对象定制方法，save和get_obj_by_id，save能自动将对象序列化到文件中，文件路径为配置文件中DB_PATH,文件名为id号，保存之前验证对象是否已经存在，若存在则抛出异常，;get_obj_by_id方法用来从文件中反序列化出对象

# 功能主题代码

import settings
import uuid
import pickle
import os


class MySQL:
    def __init__(self, host, port):
        self.host = host
        self.port = port
        self.id = self.create_id

    @property
    def create_id(self):
        return str(uuid.uuid1())

    @property
    def is_exists(self):
        tag = True
        files = os.listdir(settings.DB_PATH)
        for file in files:
            file_path = os.path.join(settings.DB_PATH, file)
            # print(file_path)
            with open(file_path, 'rb') as fr:
                obj = pickle.load(fr)
                if self.host == obj.host and self.port == obj.port:
                    tag = False
                    break
        return tag

    def save(self):
        if self.is_exists:
            path = os.path.join(settings.DB_PATH, str(self.id))
            with open(path, 'wb')as fw:
                pickle.dump(self, fw)
            print('保存成功！')
        else:
            print('对象已存在')

    def get_obj_by_id(id):
        path = os.path.join(settings.DB_PATH, id)
        if os.path.exists(path):
            with open(path, 'rb')as fr:
                obj = pickle.load(fr)
                return obj
        else:
            print('文件不存在')

    @property
    def from_conf(self):
        return settings.HOSTS, settings.PORT


mysql1 = MySQL("127.0.0.1","3306")
id = mysql1.create_id
print(id)
mysql1.save()
obj = MySQL.get_obj_by_id('eeebefac-ec27-11e9-840a-701ce72cb960')
print(obj)

2、定义一个类：圆形，该类有半径，周长，面积等属性，将半径隐藏起来，将周长与面积开放

import math


class Circle:
    def __init__(self, radius):
        self.__radius = radius

    @property
    def area(self):
        return math.pi * self.__radius ** 2

    @property
    def perimeter(self):
        return 2 * math.pi * self.__radius


c = Circle(10)
# print(c._Circle__radius)

print(c.area)
print(c.perimeter)

'''
314.1592653589793
62.83185307179586
'''

3、使用abc模块定义一个phone抽象类 并编写一个具体的实现类

import abc


class Phone(metaclass=abc.ABCMeta):
    @abc.abstractmethod
    def call(self):
        print('打电话')

    @abc.abstractmethod
    def send_msg(self):
        print('发消息')

    @abc.abstractmethod
    def play_games(self):
        print('玩游戏')


class Smartisan_OS(Phone):
    def call(self):
        print('打电话')

    def send_msg(self):
        print('发信息')

    def play_games(self):
        print('玩游戏')

p1 = Smartisan_OS()
p1.call()