面向对象之绑定方法、类方法和静态方法等相关内容-25

1.封装

"""
1、封装（略）
2、在封装的基础上，我可以将装到对象或者类中的属性给隐藏起来
注意：
    （1）在定义类或者初始化对象时，在属性前加__,就会将该属性隐藏起来
        但该隐藏起始只是一种变形_类名__属性名，并没有真的隐藏起来
​
    （2）该变形操作是在类定义阶段扫描语法时发生的变形，类定义之后添加的__开头的属性不会发生变形
​
    （3）该隐藏是对外不对内
​
    (4) 在继承中，父类如果不想让子类覆盖自己的方法，可以将方法定义为私有的？？？
"""
# 例1
# class Student:
#     __school = "oldboy"  # _Student__school = "oldboy"
#
#     def __init__(obj, x, y, z):
#         obj.__name = x  # obj._Student__name = x
#         obj.age = y
#         obj.gender = z
#
#     def __choose(self):  # obj._Student__choose
#         print("%s 正在选课" %self.name)
#
# stu_obj1 = Student("冯疯子", 18, "female")
# stu_obj1.__x=111
# print(stu_obj1.__dict__)
# print(stu_obj1.__x)
​
# print(stu_obj1.__dict__)
# print(stu_obj1._Student__name)
​
# print(Student.__dict__)
# print(Student._Student__school)
# print(stu_obj1._Student__school)
​
# 隐藏属性的意义何在
# 1、把数据属性隐藏起来的意义是：在类内开放接口，让外界使用者通过接口来操作属性值，我们可以在接口之上附加任意的逻辑
#                               来严格控制外界使用者对属性的操作
​
# class Student:
#     __school = "oldboy"  # _Student__school = "oldboy"
#
#     def __init__(obj, x, y, z):
#         obj.__name = x  # obj._Student__name = x
#         obj.__age = y
#         obj.gender = z
#
#     def __choose(self):  # obj._Student__choose
#         print("%s 正在选课" % self.name)
#
#     def get_name(self):
#         print(self.__name)  # print(self._Student__name)
#
#     def set_age(self,x):
#         if type(x) is not int:
#             print("年龄必须是整型，傻叉")
#             return
#         self.__age = x
#
#     def get_age(self):
#         print(self.__age)
#
#     def del_age(self):
#         del self.__age
#
# stu_obj1 = Student("冯疯子", 18, "female")
# # stu_obj1.get_name()
#
#
# # stu_obj1.set_age("asfdasfdasfafd")
# stu_obj1.set_age(19)
# stu_obj1.get_age()
# # print(stu_obj1.__dict__)
​
# 2、把功能属性隐藏起来:隔离复杂度
# class ATM:
#     def __card(self):
#         print('插卡')
#     def __auth(self):
#         print('用户认证')
#     def __input(self):
#         print('输入取款金额')
#     def __print_bill(self):
#         print('打印账单')
#     def __take_money(self):
#         print('取款')
#
#     def withdraw(self):
#         self.__card()
#         self.__auth()
#         self.__input()
#         self.__print_bill()
#         self.__take_money()
#
# a=ATM()
# a.withdraw()

2.property

# 例1
# class People:
#     def __init__(self, name, height, weight):
#         self.name = name
#         self.height = height
#         self.weight = weight
#
#     @property
#     def bmi(self):
#         return self.weight / (self.height ** 2)
#
# p = People('egon', 1.81, 70)
# p.height = 1.84
# print(p.bmi())
​
# 例2
# class Student:
#     __school = "oldboy"  # _Student__school = "oldboy"
#
#     def __init__(obj, x, y, z):
#         obj.__name = x
#         obj.__age = y
#         obj.gender = z
#
#     def get_name(self):
#         print("访问控制")
#         return self.__name
#
#     def set_name(self,x):
#         print("赋值控制")
#         self.__name = x
#
#     def del_name(self):
#         print("删除控制")
#         del self.__name
#
#     def get_age(self):
#         return self.__age
#
#     def set_age(self, x):
#         if type(x) is not int:
#             print("年龄必须是整型，傻叉")
#             return
#         self.__age = x
#
#     def del_age(self):
#         print("不让删")
#
#
#     age = property(get_age, set_age, del_age)
#     name = property(get_name, set_name, del_name)
#
#
# stu_obj1 = Student("冯疯子", 18, "female")
#
# # print(stu_obj1.age)
# # stu_obj1.age = "19"
# # del stu_obj1.age
# # print(stu_obj1.age)
#
#
# print(stu_obj1.name)
# # stu_obj1.name="EGON"
# # del stu_obj1.name
​
# 例3:
class Student:
    __school = "oldboy"  # _Student__school = "oldboy"
​
    def __init__(obj, x, y, z):
        obj.__name = x
        obj.__age = y
        obj.gender = z
​
    @property
    def name(self):
        print("访问控制")
        return self.__name
​
    @name.setter
    def name(self, x):
        print("赋值控制")
        self.__name = x
​
    @name.deleter
    def name(self):
        print("删除控制")
        del self.__name
​
​
stu_obj1 = Student("冯疯子", 18, "female")
​
stu_obj1.name

3.绑定方法与非绑定方法

# 类中的定义的函数
# 1 绑定方法:谁来调用就会将谁当作第一个参数传入
#  (1)绑定给对象的方法:类中定义的函数默认就是绑定给对象的方法,应该是由对象调用,会把对象当作第一个参数传入
#  (2)绑定给类的方法:在类中的函数上加一个装饰器@classmethod,该函数就绑定给类了,应该是由类来调用,会把类当作第一个参数传入
​
# 2 非绑定方法:既不与类绑定也不与对象绑定,就是一个普通的函数,谁都可以来调用,没有自动传参的效果,
#  在函数上添加装饰器@staticmethod
#
# class People:
#     def __init__(self, name, age):
#         self.name = name
#         self.age = age
#
#     def tell_info(self):
#         print("<%s:%s>" % (self.name, self.age))
#
#     @classmethod
#     def f1(cls):
#         print(cls)
#
#     @staticmethod
#     def f2(x,y,z):
#         print(x,y,z)
#
#
# p1=People('egon',18)
# # p1.tell_info()
#
# # print(p1.tell_info)
# # print(People.f1)
#
# # People.f1()
#
# # print(p1.f2)
# # print(People.f2)
# p1.f2(1,2,3)
# People.f2(1,2,3)
​
# 例如:
import uuid
import settings
​
class MySQL:
    def __init__(self,ip,port):
        self.mid = self.__create_id()
        self.ip = ip
        self.port = port
​
    def tell_info(self):
        print("%s:<%s:%s>" %(self.mid,self.ip,self.port))
​
    @staticmethod
    def __create_id():
        return uuid.uuid4()
​
    @classmethod
    def from_conf(cls):
        return cls(settings.IP, settings.PORT)
​
# obj = MySQL("10.10.11.11",3306)
# obj.tell_info()
​
​
obj1=MySQL.from_conf()
obj1.tell_info()