Python,设计模式,抽象工厂模式
后端开发-Python教程
抽象工厂模式：提供一个创建一系列相关或相互依赖对象的接口，而无需指定它们具体的类。优点：易于交换“产品系列”，只要更改相应的工厂即可。
缺点：建立产品的时候很繁琐，需要增加和修改很多东西。
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优化1：为了避免客户端有过多的逻辑判断，可以封装出一个简单工厂类来生成产品类。优化2：为了减少简单工厂类里面的逻辑判断，可以采用“反射”机制，直接根据外部的配置文件读取出需要使用产品类的信息。
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#encoding=utf-8 # #by panda #抽象工厂模式 def printInfo(info): print unicode(info, 'utf-8').encode('gbk') #抽象产品A：user表 class IUser(): def Insert(self): pass def GetUser(self): pass #sqlserver实现的User class SqlserverUser(IUser): def Insert(self): printInfo("在SQL Server中给User表增加一条记录") def GetUser(self): printInfo("在SQL Server中得到User表的一条记录") #Access实现的User class AccessUser(IUser): def Insert(self): printInfo("在Access中给User表增加一条记录") def GetUser(self): printInfo("在Access中得到User表一条记录") #抽象产品B：部门表 class IDepartment(): def Insert(self): pass def GetUser(self): pass #sqlserver实现的Department class SqlserverDepartment(IUser): def Insert(self): printInfo("在SQL Server中给Department表增加一条记录") def GetUser(self): printInfo("在SQL Server中得到Department表的一条记录") #Access实现的Department class AccessDepartment(IUser): def Insert(self): printInfo("在Access中给Department表增加一条记录") def GetUser(self): printInfo("在Access中得到Department表一条记录") #抽象工厂 class IFactory(): def CreateUser(self): pass def CreateDepartment(self): pass #sql server工厂 class SqlServerFactory(IFactory): def CreateUser(self): return SqlserverUser() def CreateDepartment(self): return SqlserverDepartment() #access工厂 class AccessFactory(IFactory): def CreateUser(self): return AccessUser() def CreateDepartment(self): return AccessDepartment() #优化一：采用一个简单工厂类，封装逻辑判断操作 class DataAccess(): # db = "Sqlserver" db = "Access" @staticmethod def CreateUser(): if (DataAccess.db == "Sqlserver"): return SqlserverUser() elif(DataAccess.db == "Access"): return AccessUser() @staticmethod def CreateDepartment(): if (DataAccess.db == "Sqlserver"): return SqlserverDepartment() elif(DataAccess.db == "Access"): return AccessDepartment() #优化二：采用反射机制，避免使用太多判断 ##以下信息可以从配置文件中获取 DBType = 'Sqlserver' #'Access' DBTab_User = 'User' DBTab_Department = 'Department' class DataAccessPro(): # db = "Sqlserver" db = "Access" @staticmethod def CreateUser(): funName = DBType + DBTab_User return eval(funName)() #eval 将其中的字符串转化为python表达式 @staticmethod def CreateDepartment(): funName = DBType + DBTab_Department return eval(funName)() def clientUI(): printInfo("\n--------抽象工厂方法--------") factory = SqlServerFactory() iu = factory.CreateUser() iu.Insert() iu.GetUser() id = factory.CreateDepartment() id.Insert() id.GetUser() printInfo("\n--抽象工厂方法+简单工厂方法--") iu = DataAccess.CreateUser() iu.Insert() iu.GetUser() id = DataAccess.CreateDepartment() id.Insert() id.GetUser() printInfo("\n-抽象工厂方法+简单工厂方法+反射-") iu = DataAccessPro.CreateUser() iu.Insert() iu.GetUser() id = DataAccessPro.CreateDepartment() id.Insert() id.GetUser() return if __name__ == '__main__': clientUI(); 带手机版云购源码,vscode函数着色,ubuntu设置在哪,tomcat 设置大小,sqlite3显示中文,爬虫在手机上能练习吗,php身份证号码,seo优化话术,asp微信网站源码,如何在电视直播网页提取直播源码,系统维护手册模板lzw
类图：工厂模式和抽象工厂模式的区别：工厂模式是在派生类中定义一个工厂的抽象接口，然后基类负责创建具体对象；抽象工厂模式是维护一个产品家族，由基类定义产品被生产的方法，客户根据派生类的接口进行开发。
实例：人民群众喜闻乐见的披萨店例子这里又可以搬出来了，这次我们根据抽象工厂模式的特点，用不同原材料制作不同口味的披萨，创建不同原材料的工厂，不同实体店做出口味不同的披萨。创建一个产品家族（Dough、Sauce、Cheese和Clam）的抽象类型（PizzaIngredientFactory），这个类型的子类（NYPizzaIngredientFactory和ChicagoPizzaIngredientFactory）定义了产品被产生的方法。
代码：
#!/usr/bin/python# -*- coding:utf-8 -*-import sysreload(sys)sys.setdefaultencoding('utf-8') '''披萨'''class Pizza: name = "" dough = None sauce = None cheese = None clam = None def prepare(self): pass def bake(self): print "烘烤25分钟在350。".decode('utf-8') def cut(self): print "切割成对角线切片。".decode('utf-8') def box(self): print "放在官方的盒子中。".decode('utf-8') def get_name(self): return self.name def set_name(self, name): self.name = name def to_string(self): string = "%s:\n" % self.name string += " 面团: %s\n" % self.dough.to_string() if self.dough else "" string += " 酱汁: %s\n" % self.sauce.to_string() if self.sauce else "" string += " 奶酪: %s\n" % self.cheese.to_string() if self.cheese else "" string += " 文蛤: %s\n" % self.clam.to_string() if self.clam else "" return string '''什么类别的披萨'''class CheesePizza(Pizza): def __init__(self, ingredient_factory): self.ingredient_factory = ingredient_factory def prepare(self): print "准备: %s" % self.name self.dough = self.ingredient_factory.create_dough() self.sauce = self.ingredient_factory.create_sauce() self.cheese = self.ingredient_factory.create_cheese() class ClamPizza(Pizza): def __init__(self, ingredient_factory): self.ingredient_factory = ingredient_factory def prepare(self): print "准备: %s" % self.name self.dough = self.ingredient_factory.create_dough() self.sauce = self.ingredient_factory.create_sauce() self.clam = self.ingredient_factory.create_clam() '''披萨店'''class PizzaStore: def order_pizza(self, pizza_type): self.pizza = self.create_pizza(pizza_type) self.pizza.prepare() self.pizza.bake() self.pizza.cut() self.pizza.box() return self.pizza def create_pizza(self, pizza_type): pass '''纽约披萨实体店1'''class NYPizzaStore(PizzaStore): def create_pizza(self, pizza_type): ingredient_factory = NYPizzaIngredientFactory() if pizza_type == "cheese": pizza = CheesePizza(ingredient_factory) pizza.set_name("纽约风格芝士披萨".decode('utf-8')) elif pizza_type == "clam": pizza = ClamPizza(ingredient_factory) pizza.set_name("纽约风格文蛤披萨".decode('utf-8')) else: pizza = None return pizza '''芝加哥披萨实体店2'''class ChicagoPizzaStore(PizzaStore): def create_pizza(self, pizza_type): ingredient_factory = ChicagoPizzaIngredientFactory() if pizza_type == "cheese": pizza = CheesePizza(ingredient_factory) pizza.set_name("芝加哥风格芝士披萨".decode('utf-8')) elif pizza_type == "clam": pizza = ClamPizza(ingredient_factory) pizza.set_name("芝加哥风格文蛤披萨".decode('utf-8')) else: pizza = None return pizza '''生产披萨的工厂'''class PizzaIngredientFactory: def create_dough(self): pass def create_sauce(self): pass def create_cheese(self): pass def create_clam(self): pass '''生产披萨的实体工厂1'''class NYPizzaIngredientFactory(PizzaIngredientFactory): def create_dough(self): return ThinDough() def create_sauce(self): return MarinaraSauce() def create_cheese(self): return FreshCheese() def create_clam(self): return FreshClam() '''生产披萨的实体工厂2'''class ChicagoPizzaIngredientFactory(PizzaIngredientFactory): def create_dough(self): return ThickDough() def create_sauce(self): return MushroomSauce() def create_cheese(self): return BlueCheese() def create_clam(self): return FrozenClam() class Dough: def to_string(self): pass class ThinDough(Dough): def to_string(self): return "薄的面团" class ThickDough(Dough): def to_string(self): return "厚的生面团" class Sauce: def to_string(self): pass class MarinaraSauce(Sauce): def to_string(self): return "番茄酱" class MushroomSauce(Sauce): def to_string(self): return "蘑菇酱" class Cheese: def to_string(self): pass class FreshCheese(Cheese): def to_string(self): return "新鲜的奶酪" class BlueCheese(Cheese): def to_string(self): return "蓝纹奶酪" class Clam: def to_string(self): pass class FreshClam(Clam): def to_string(self): return "新鲜的文蛤" class FrozenClam(Clam): def to_string(self): return "冷冻的文蛤" if __name__ == "__main__": # 创建了两个披萨实体店 ny_store = NYPizzaStore() chicago_store = ChicagoPizzaStore() # 在第一个披萨对象中订购了一个cheese风味的披萨 pizza = ny_store.order_pizza("cheese") print pizza.to_string() print "迈克订购了一个 %s" % pizza.get_name() print pizza = chicago_store.order_pizza("clam") print pizza.to_string() print "约翰订购了一个%s" % pizza.get_name()结果：
准备: 纽约风格芝士披萨烘烤25分钟在350。切割成对角线切片。放在官方的盒子中。纽约风格芝士披萨: 面团: 薄的面团 酱汁: 番茄酱 奶酪: 新鲜的奶酪 迈克订购了一个 纽约风格芝士披萨 准备: 芝加哥风格文蛤披萨烘烤25分钟在350。切割成对角线切片。放在官方的盒子中。芝加哥风格文蛤披萨: 面团: 厚的生面团 酱汁: 蘑菇酱 文蛤: 冷冻的文蛤 约翰订购了一个芝加哥风格文蛤披萨