day21作业

1、定义MySQL类（参考答案：http://www.cnblogs.com/linhaifeng/articles/7341177.html#_label5）
　　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

import uuid
import pickle
import os
class Mysql:
    def __init__(self,host,port):
        self.id = self.create_id()
        self.host = host
        self.port = port
    def save(self):
        if not self.is_exists:
            raise PermissionError('对象已经存在')
        filepath = r'%s%s%s'%(settings.DB_PATH,os.sep,self.id)
        pickle.dump(self,open(filepath,'wb'))

    @property
    def is_exists(self):
        tag = True
        files = os.listdir(settings.DB_PATH)
        for file in files:
            file_abspath = r'%s%s%s'%(settings.DB_PATH,os.sep,file)
            obj = pickle.load(open(file_abspath,'rb'))
            if self.host == obj.host and self.port == obj.port:
                tag = False
                break
        return tag
    @staticmethod
    def get_obj_by_id(id):
        file_abspath = r'%s%s%s'%(settings.DB_PATH,os.sep,id)
        return pickle.load(open(file_abspath,'rb'))
    @staticmethod
    def create_id():
        return str(uuid.uuid1())
    @classmethod
    def from_conf(cls):
        print(cls)
        return cls(settings.HOST,settings.PORT)

conn = Mysql.from_conf()
conn.save()

conn1=Mysql('127.0.0.1',3306)
conn1.save()

obj=Mysql.get_obj_by_id('7e6c5ec0-7e9f-11e7-9acc-408d5c2f84ca')
print(obj.host)



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
		参考答案（http://www.cnblogs.com/linhaifeng/articles/7340801.html#_label4）

import cmath
class circle1:
    def __init__(self,radius):
        self.__radius = radius
        self.round = self.round()
        self.area = self.area()

    def round(self):
        return cmath.pi * 2 * self.__radius

    def area(self):
        return cmath.pi * self.__radius * self.__radius

aa = circle1(11)
print(aa.area)


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('call.....')
    @abc.abstractmethod
    def watch_TV(self):
        print('Watch_TV')
class Iphone(Phone):
    def call(self):
        print('call...')
    def watch_TV(self):
        print('watch_TV')
    def powerin(self):
        print('powerin')
iphone = Iphone()
iphone.call()
iphone.watch_TV()
iphone.powerin()
print(iphone)