python面向对象之依赖注入

python面向对象之依赖注入

#!/usr/bin/env python# -*- coding: utf-8 -*-

# 组合# a = a()# b = b(a)# c = c(b)# d = d(c)

#依赖注入class Mapper: __mapper_relation = {}@staticmethoddef register(cls,value): Mapper.__mapper_relation[cls]=value@staticmethoddef exist(cls):if cls in Mapper.__mapper_relation:return True return False@staticmethoddef value(cls):return Mapper.__mapper_relation[cls]class MyType(type):def __call__(cls, *args, **kwargs): obj = cls.__new__(cls,*args,**kwargs) arg_list = list(args)if Mapper.exist(cls): value = Mapper.value(cls) arg_list.append(value) obj.__init__(*arg_list,**kwargs)return objclass Foo(metaclass=MyType):def __init__(self,name):self.name=namedef f1(self):print(self.name)class Bar(metaclass=MyType):def __init__(self, name):self.name = namedef f1(self):print(self.name)#解释器解释#1，遇到class Foo，执行type的__init__方法#2，Type的init的方法里面做什么呢？不知道 C语言写的 无法修改#3，执行Type的__call__方法# 执行Foo类的__new__方法# 执行Foo类的__init__方法Mapper.register(Foo,"foo_123")Mapper.register(Bar,"bar_123")obj = Foo()print(obj.name)obj2 = Bar()print(obj2.name)

C:\Python35\python.exe D:/py_django/test/a3.py

foo_123

bar_123

Process finished with exit code 0

#!/usr/bin/env python# -*- coding: utf-8 -*-#依赖注入class Mapper: __mapper_relation = {}@staticmethoddef register(cls,value): Mapper.__mapper_relation[cls]=value@staticmethoddef exist(cls):if cls in Mapper.__mapper_relation:return True return False@staticmethoddef value(cls):return Mapper.__mapper_relation[cls]class MyType(type):def __call__(cls, *args, **kwargs): obj = cls.__new__(cls,*args,**kwargs) arg_list = list(args)if Mapper.exist(cls): value = Mapper.value(cls) arg_list.append(value) obj.__init__(*arg_list,**kwargs)return objclass BarFoo_parent:def __init__(self):passclass Foo(metaclass=MyType):def __init__(self,name):self.name=namedef f1(self):print(self.name)class Bar(metaclass=MyType):def __init__(self, name):self.name = namedef f1(self):print(self.name)#解释器解释#1，遇到class Foo，执行type的__init__方法#2，Type的init的方法里面做什么呢？不知道 C语言写的 无法修改#3，执行Type的__call__方法# 执行Foo类的__new__方法# 执行Foo类的__init__方法Mapper.register(Foo,BarFoo_parent())Mapper.register(Bar,Foo())obj2 = Bar()print(obj2)print(obj2.name)print(obj2.name.name)

C:\Python35\python.exe D:/py_django/test/a4.py

<__main__.Bar object at 0x0000000000714710>

<__main__.Foo object at 0x00000000007146D8>

<__main__.BarFoo_parent object at 0x0000000000714630>

Process finished with exit code 0

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