1.
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
HOST='127.0.0.1'
PORT=3306
DB_PATH=r'E:CMSaaadb'
'''
from conf import settings
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('对象已存在')
file_path=r'%s%s%s' %(settings.DB_PATH,os.sep,self.id)
pickle.dump(self,open(file_path,'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)
# print(MySQL.from_conf) #<bound method MySQL.from_conf of <class '__main__.MySQL'>>
conn=MySQL.from_conf()
conn.save()
conn1=MySQL('127.0.0.1',3306)
conn1.save() #抛出异常PermissionError: 对象已存在
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.
import math
class Circle:
def __init__(self): # 传入○的半径
self.__bj = 2 # 隐藏半径属性
# 使用property装饰器当做属性引用
@property
def area(self): # 计算面积
return math.pi * self.__bj**2
@property
def zc(self):
return 2*math.pi*self.__bj
tea1 = Circle()
print(tea1.area) # 求该圆的面积
print(tea1.zc) # 圆的周长
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 play(self):
pass
@abc.abstractmethod
def photo_phone(self):
pass
class hongmi(Phone):
# 子类继承父类的属性,必须遵循父类的规范
def play(self):
pass
def photo_phone(self):
pass