标签：pen 圆形 err 技术分享 nbsp src with open upd com
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 os import time import pickle import hashlib import settings class Mysql: def __init__(self,host,port): self.id = self.creta_id() self.host =host self.port = port @staticmethod def creta_id(): m = hashlib.md5() m.update(str(time.clock()).encode(‘utf-8‘)) return m.hexdigest() def save(self): path = os.path.join(settings.DB_path,‘%s.pickle‘ %self.id) if os.path.isfile(path): raise IOError(‘对象已存在‘) else: with open(path,‘wb‘) as f: pickle.dump(self,f) @staticmethod def get_obj_by_id(id): path = os.path.join(settings.DB_path, ‘%s.pickle‘ %id) if os.path.isfile(path): with open(path,‘rb‘) as f: return pickle.load(f) else: raise IOError(‘对象不存在‘) def tell(self): print(‘id:%s,host:%s,port:%s‘ %(self.id,self.host,self.port)) @classmethod def from_conf(cls): return cls(settings.HOST,settings.PORT) # mysql = Mysql(‘127.0.0.1‘,‘3309‘) # mysql = Mysql.from_conf() # mysql.save() # mysql.tell() # f = Mysql.get_obj_by_id(‘30565a8911a6bb487e3745c0ea3c8224‘) # f.tell()
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 math class Round: def __init__(self,radius): self.__radius = radius @property def radius(self): return self.__radius @radius.setter def radius(self,x): self.__radius = x def perimeter(self): round_perimeter = math.pi *(self.__radius * 2) return round_perimeter def area(self): round_area = math.pi * (self.__radius * self.__radius) return round_area round1 = Round(3) print(round1.perimeter()) print(round1.area()) round1.radius = 4 print(round1.perimeter()) print(round1.area())
标签：pen 圆形 err 技术分享 nbsp src with open upd com
原文地址：https://www.cnblogs.com/guodengjian/p/8856668.html
