Python之常用设计模式

1、 设计模式

2、接口

interface.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# Date: 2018/12/1

# class Payment:
#     def pay(self, money):
#         raise NotImplementedError

from abc import ABCMeta, abstractmethod


# 接口
# class Payment(metaclass=ABCMeta):
#     # abstract class
#     @abstractmethod
#     def pay(self, money):
#         pass
#
#
# class Alipay(Payment):
#     def pay(self, money):
#         print("支付宝支付%d元." % money)
#
#
# class WechatPay(Payment):
#     def pay(self, money):
#         print("微信支付%d元." % money)
#
#
#
# p = WechatPay()
# p.pay(100)

#
# class User:
#     def show_name(self):
#         pass
#
# class VIPUser(User):
#     def show_name(self):
#         pass
#
# def show_user(u):
#     res = u.show_name()

class LandAnimal(metaclass=ABCMeta):
    @abstractmethod
    def walk(self):
        pass


class WaterAnimal(metaclass=ABCMeta):
    @abstractmethod
    def swim(self):
        pass


class SkyAnimal(metaclass=ABCMeta):
    @abstractmethod
    def fly(self):
        pass


class Tiger(LandAnimal):
    def walk(self):
        print("老虎走路")


class Frog(LandAnimal, WaterAnimal):
    pass

3、面向对象设计SOLID原则

4、设计模式分类

5、创建型模式

1）简单工厂模式

factory.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# Date: 2018/12/1

from abc import ABCMeta, abstractmethod


class Payment(metaclass=ABCMeta):
    # abstract class
    @abstractmethod
    def pay(self, money):
        pass

class Alipay(Payment):
    def __init__(self, use_huabei=False):
        self.use_huaei = use_huabei

    def pay(self, money):
        if self.use_huaei:
            print("花呗支付%d元." % money)
        else:
            print("支付宝余额支付%d元." % money)


class WechatPay(Payment):
    def pay(self, money):
        print("微信支付%d元." % money)


class PaymentFactory:
    def create_payment(self, method):
        if method == 'alipay':
            return Alipay()
        elif method == 'wechat':
            return WechatPay()
        elif method == 'huabei':
            return Alipay(use_huabei=True)
        else:
            raise TypeError("No such payment named %s" % method)



# client
pf = PaymentFactory()
p = pf.create_payment('huabei')
p.pay(100)

2）工厂方法模式

factory_method.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# Date: 2018/12/1

from abc import ABCMeta, abstractmethod


class Payment(metaclass=ABCMeta):
    # abstract class
    @abstractmethod
    def pay(self, money):
        pass


class Alipay(Payment):
    def __init__(self, use_huabei=False):
        self.use_huaei = use_huabei

    def pay(self, money):
        if self.use_huaei:
            print("花呗支付%d元." % money)
        else:
            print("支付宝余额支付%d元." % money)


class WechatPay(Payment):
    def pay(self, money):
        print("微信支付%d元." % money)


class BankPay(Payment):
    def pay(self, money):
        print("银行卡支付%d元." % money)


class PaymentFactory(metaclass=ABCMeta):
    @abstractmethod
    def create_payment(self):
        pass


class AlipayFactory(PaymentFactory):
    def create_payment(self):
        return Alipay()


class WechatPayFactory(PaymentFactory):
    def create_payment(self):
        return WechatPay()


class HuabeiFactory(PaymentFactory):
    def create_payment(self):
        return Alipay(use_huabei=True)


class BankPayFactory(PaymentFactory):
    def create_payment(self):
        return BankPay()


# client

pf = HuabeiFactory()
p = pf.create_payment()
p.pay(100)

3）抽象工厂模式

abstract_factory.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# Date: 2018/12/1

from abc import abstractmethod, ABCMeta


# ------抽象产品------

class PhoneShell(metaclass=ABCMeta):
    @abstractmethod
    def show_shell(self):
        pass


class CPU(metaclass=ABCMeta):
    @abstractmethod
    def show_cpu(self):
        pass


class OS(metaclass=ABCMeta):
    @abstractmethod
    def show_os(self):
        pass


# ------抽象工厂------

class PhoneFactory(metaclass=ABCMeta):
    @abstractmethod
    def make_shell(self):
        pass

    @abstractmethod
    def make_cpu(self):
        pass

    @abstractmethod
    def make_os(self):
        pass


# ------具体产品------


class SmallShell(PhoneShell):
    def show_shell(self):
        print("普通手机小手机壳")


class BigShell(PhoneShell):
    def show_shell(self):
        print("普通手机大手机壳")


class AppleShell(PhoneShell):
    def show_shell(self):
        print("苹果手机壳")


class SnapDragonCPU(CPU):
    def show_cpu(self):
        print("骁龙CPU")


class MediaTekCPU(CPU):
    def show_cpu(self):
        print("联发科CPU")


class AppleCPU(CPU):
    def show_cpu(self):
        print("苹果CPU")


class Android(OS):
    def show_os(self):
        print("Android系统")


class IOS(OS):
    def show_os(self):
        print("iOS系统")


# ------具体工厂------


class MiFactory(PhoneFactory):
    def make_cpu(self):
        return SnapDragonCPU()

    def make_os(self):
        return Android()

    def make_shell(self):
        return BigShell()


class HuaweiFactory(PhoneFactory):
    def make_cpu(self):
        return MediaTekCPU()

    def make_os(self):
        return Android()

    def make_shell(self):
        return SmallShell()


class IPhoneFactory(PhoneFactory):
    def make_cpu(self):
        return AppleCPU()

    def make_os(self):
        return IOS()

    def make_shell(self):
        return AppleShell()


# ------客户端------


class Phone:
    def __init__(self, cpu, os, shell):
        self.cpu = cpu
        self.os = os
        self.shell = shell

    def show_info(self):
        print("手机信息:")
        self.cpu.show_cpu()
        self.os.show_os()
        self.shell.show_shell()



def make_phone(factory):
    cpu = factory.make_cpu()
    os = factory.make_os()
    shell = factory.make_shell()
    return Phone(cpu, os, shell)


p1 = make_phone(IPhoneFactory())
p1.show_info()

4）建造者模式

builder.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# Date: 2018/12/1

from abc import ABCMeta, abstractmethod

class Player:
    def __init__(self, face=None, body=None, arm=None, leg=None):
        self.face = face
        self.body = body
        self.arm = arm
        self.leg = leg

    def __str__(self):
        return "%s, %s, %s, %s" % (self.face, self.body, self.arm, self.leg)


class PlayerBuilder(metaclass=ABCMeta):
    @abstractmethod
    def build_face(self):
        pass

    @abstractmethod
    def build_body(self):
        pass

    @abstractmethod
    def build_arm(self):
        pass

    @abstractmethod
    def build_leg(self):
        pass


class SexyGirlBuilder(PlayerBuilder):
    def __init__(self):
        self.player = Player()

    def build_face(self):
        self.player.face = "漂亮脸蛋"

    def build_body(self):
        self.player.body = "苗条"

    def build_arm(self):
        self.player.arm = "漂亮胳膊"

    def build_leg(self):
        self.player.leg = "大长腿"


class Monster(PlayerBuilder):
    def __init__(self):
        self.player = Player()

    def build_face(self):
        self.player.face = "怪兽脸"

    def build_body(self):
        self.player.body = "怪兽身材"

    def build_arm(self):
        self.player.arm = "长毛的胳膊"

    def build_leg(self):
        self.player.leg = "长毛的腿"


class PlayerDirector: # 控制组装顺序
    def build_player(self, builder):
        builder.build_body()
        builder.build_face()
        builder.build_arm()
        builder.build_leg()
        return builder.player


# client

builder = Monster()
director = PlayerDirector()
p = director.build_player(builder)
print(p)

5）单例模式

singleton.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# Date: 2018/12/1

from abc import abstractmethod, ABCMeta

class Singleton:
    def __new__(cls, *args, **kwargs):
        if not hasattr(cls, "_instance"):
            cls._instance = super(Singleton, cls).__new__(cls)
        return cls._instance


class MyClass(Singleton):
    def __init__(self, a):
        self.a = a


a = MyClass(10)
b = MyClass(20)

print(a.a)
print(b.a)
print(id(a), id(b))

6）创建型模式小结

6、结构型模式

1）适配器模式

adapter.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# Date: 2018/12/1

from abc import ABCMeta, abstractmethod


class Payment(metaclass=ABCMeta):
    # abstract class
    @abstractmethod
    def pay(self, money):
        pass


class Alipay(Payment):
    def pay(self, money):
        print("支付宝支付%d元." % money)


class WechatPay(Payment):
    def pay(self, money):
        print("微信支付%d元." % money)



class BankPay:
    def cost(self, money):
        print("银联支付%d元." % money)


class ApplePay:
    def cost(self, money):
        print("苹果支付%d元." % money)


# # 类适配器
# class NewBankPay(Payment, BankPay):
#     def pay(self, money):
#         self.cost(money)


# 对象适配器
class PaymentAdapter(Payment):
    def __init__(self, payment):
        self.payment = payment

    def pay(self, money):
        self.payment.cost(money)


p = PaymentAdapter(BankPay())
p.pay(100)


# 组合

# class A:
#     pass
#
# class B:
#     def __init__(self):
#         self.a = A()

2）桥模式

bridge.py

# coding: utf-8
# author: ztypl
# date:   2018/12/20

from abc import ABCMeta, abstractmethod

class Shape(metaclass=ABCMeta):
    def __init__(self, color):
        self.color = color

    @abstractmethod
    def draw(self):
        pass


class Color(metaclass=ABCMeta):
    @abstractmethod
    def paint(self, shape):
        pass


class Rectangle(Shape):
    name = "长方形"
    def draw(self):
        # 长方形逻辑
        self.color.paint(self)


class Circle(Shape):
    name = "圆形"
    def draw(self):
        # 圆形逻辑
        self.color.paint(self)


class Line(Shape):
    name = "直线"
    def draw(self):
        # 直线逻辑
        self.color.paint(self)


class Red(Color):
    def paint(self, shape):
        print("红色的%s" % shape.name)


class Green(Color):
    def paint(self, shape):
        print("绿色的%s" % shape.name)


class Blue(Color):
    def paint(self, shape):
        print("蓝色的%s" % shape.name)



shape = Line(Blue())
shape.draw()

shape2 = Circle(Green())
shape2.draw()

3）组合模式

composite.py

# coding: utf-8
# author: ztypl
# date:   2018/12/21

from abc import ABCMeta, abstractmethod


# 抽象组件
class Graphic(metaclass=ABCMeta):
    @abstractmethod
    def draw(self):
        pass


# 叶子组件
class Point(Graphic):
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __str__(self):
        return "点(%s, %s)" % (self.x, self.y)

    def draw(self):
        print(str(self))


# 叶子组件
class Line(Graphic):
    def __init__(self, p1, p2):
        self.p1 = p1
        self.p2 = p2

    def __str__(self):
        return "线段[%s, %s]" % (self.p1, self.p2)

    def draw(self):
        print(str(self))


# 复合组件
class Picture(Graphic):
    def __init__(self, iterable):
        self.children = []
        for g in iterable:
            self.add(g)

    def add(self, graphic):
        self.children.append(graphic)


    def draw(self):
        print("------复合图形------")
        for g in self.children:
            g.draw()
        print("------复合图形------")


p1 = Point(2,3)
l1 = Line(Point(3,4), Point(6,7))
l2 = Line(Point(1,5), Point(2,8))
pic1 = Picture([p1, l1, l2])

p2 = Point(4,4)
l3 = Line(Point(1,1), Point(0,0))
pic2 = Picture([p2, l3])

pic = Picture([pic1, pic2])
pic.draw()

4）外观模式

facade.py

# coding: utf-8
# author: ztypl
# date:   2018/12/26


class CPU:
    def run(self):
        print("CPU开始运行")

    def stop(self):
        print("CPU停止运行")


class Disk:
    def run(self):
        print("硬盘开始工作")

    def stop(self):
        print("硬盘停止工作")


class Memory:
    def run(self):
        print("内存通电")

    def stop(self):
        print("内存断电")


class Computer: # Facade
    def __init__(self):
        self.cpu = CPU()
        self.disk = Disk()
        self.memory = Memory()

    def run(self):
        self.cpu.run()
        self.disk.run()
        self.memory.run()

    def stop(self):
        self.cpu.stop()
        self.disk.stop()
        self.memory.stop()


# Client

computer = Computer()
computer.run()
computer.stop()

5）代理模式

proxy.py

# coding: utf-8
# author: ztypl
# date:   2018/12/26

from abc import ABCMeta, abstractmethod

class Subject(metaclass=ABCMeta):
    @abstractmethod
    def get_content(self):
        pass

    @abstractmethod
    def set_content(self, content):
        pass


class RealSubject(Subject):
    def __init__(self, filename):
        self.filename = filename
        f = open(filename, 'r', encoding='utf-8')
        print("读取文件内容")
        self.content = f.read()
        f.close()

    def get_content(self):
        return self.content

    def set_content(self, content):
        f = open(self.filename, 'w', encoding='utf-8')
        f.write(content)
        f.close()





class VirtualProxy(Subject):
    def __init__(self, filename):
        self.filename = filename
        self.subj = None

    def get_content(self):
        if not self.subj:
            self.subj = RealSubject(self.filename)
        return self.subj.get_content()


    def set_content(self, content):
        if not subj:
            self.subj = RealSubject(self.filename)
        return self.subj.set_content(content)



class ProtectedProxy(Subject):
    def __init__(self, filename):
        self.subj = RealSubject(filename)

    def get_content(self):
        return self.subj.get_content()

    def set_content(self, content):
        raise PermissionError("无写入权限")



#subj = RealSubject("test.txt")
#subj.get_content()

subj = ProtectedProxy("test.txt")
print(subj.get_content())
subj.set_content("abc")

7、行为型模式

1）责任链模式

chain_of_responsibility.py

# coding: utf-8
# author: ztypl
# date:   2018/12/26

from abc import ABCMeta, abstractmethod

class Handler(metaclass=ABCMeta):
    @abstractmethod
    def handle_leave(self, day):
        pass


class GeneralManager(Handler):
    def handle_leave(self, day):
        if day <= 10:
            print("总经理准假%d天" % day)
        else:
            print("你还是辞职吧")


class DepartmentManager(Handler):
    def __init__(self):
        self.next = GeneralManager()

    def handle_leave(self, day):
        if day <= 5:
            print("部门经理准假%s天" % day)
        else:
            print("部门经理职权不足")
            self.next.handle_leave(day)


class ProjectDirector(Handler):
    def __init__(self):
        self.next = DepartmentManager()

    def handle_leave(self, day):
        if day <= 3:
            print("项目主管准假%d天" % day)
        else:
            print("项目主管职权不足")
            self.next.handle_leave(day)

# Client


day = 12
h = ProjectDirector()
h.handle_leave(day)

2)观察者模式

observer.py

# coding: utf-8
# author: ztypl
# date:   2018/12/27

from abc import ABCMeta, abstractmethod


class Observer(metaclass=ABCMeta): # 抽象订阅者
    @abstractmethod
    def update(self, notice): # notice 是一个Notice类的对象
        pass


class Notice:  # 抽象发布者
    def __init__(self):
        self.observers = []

    def attach(self, obs):
        self.observers.append(obs)

    def detach(self, obs):
        self.observers.remove(obs)

    def notify(self): # 推送
        for obs in self.observers:
            obs.update(self)


class StaffNotice(Notice): # 具体发布者
    def __init__(self, company_info=None):
        super().__init__()
        self.__company_info = company_info

    @property
    def company_info(self):
        return self.__company_info

    @company_info.setter
    def company_info(self, info):
        self.__company_info = info
        self.notify() # 推送


class Staff(Observer):
    def __init__(self):
        self.company_info = None

    def update(self, notice):
        self.company_info = notice.company_info


# Client

notice = StaffNotice("初始公司信息")
s1 = Staff()
s2 = Staff()
notice.attach(s1)
notice.attach(s2)
notice.company_info = "公司今年业绩非常好，给大家发奖金！！！"
print(s1.company_info)
print(s2.company_info)
notice.detach(s2)
notice.company_info = "公司明天放假！！！"
print(s1.company_info)
print(s2.company_info)

3）策略模式

strategy.py

# coding: utf-8
# author: ztypl
# date:   2018/12/27

from abc import ABCMeta,abstractmethod

class Strategy(metaclass=ABCMeta):
    @abstractmethod
    def execute(self, data):
        pass


class FastStrategy(Strategy):
    def execute(self, data):
        print("用较快的策略处理%s" % data)


class SlowStrategy(Strategy):
    def execute(self, data):
        print("用较慢的策略处理%s" % data)


class Context:
    def __init__(self, strategy, data):
        self.data = data
        self.strategy = strategy

    def set_strategy(self, strategy):
        self.strategy = strategy

    def do_strategy(self):
        self.strategy.execute(self.data)


# Client

data = "[...]"
s1 = FastStrategy()
s2 = SlowStrategy()
context = Context(s1, data)
context.do_strategy()
context.set_strategy(s2)
context.do_strategy()

4）模板方法模式

template_method.py

# coding: utf-8
# author: ztypl
# date:   2018/12/27

from abc import ABCMeta, abstractmethod
from time import sleep


class Window(metaclass=ABCMeta):
    @abstractmethod
    def start(self):
        pass

    @abstractmethod
    def repaint(self):
        pass

    @abstractmethod
    def stop(self): # 原子操作/钩子操作
        pass

    def run(self):  # 模板方法
        self.start()
        while True:
            try:
                self.repaint()
                sleep(1)
            except KeyboardInterrupt:
                break
        self.stop()


class MyWindow(Window):
    def __init__(self, msg):
        self.msg = msg

    def start(self):
        print("窗口开始运行")

    def stop(self):
        print("窗口结束运行")

    def repaint(self):
        print(self.msg)


MyWindow("Hello...").run()

8、视频链接

【Python之常用设计模式-哔哩哔哩】 https://b23.tv/P8D78qx