2019年9月23日 类的装饰器的应用

class Leixin:
    def __init__(self,k,t):#k 通过该方法将程序写活
        self.k=k
        self.t=t

    def __set__(self, instance, value):#从优先级考虑必须要有set方法，必须要定义成数据描述符，这样实例时候才能优先触发
        print('set方法',instance,value) #instance 就是实例本身p1,value就是赋给name的值。
        if not isinstance(value,self.t):
            print("%s没有传递%s格式"%(self.k,self.t))
            return
        instance.__dict__[self.k]=value #添加到实例到字典中

    def __get__(self, instance, owner):
        print('get方法',instance,owner)#owner 就是对应的类People
        return instance.__dict__[self.k] #取出实例中存储的值

def deco(**kwargs):#通过函数的嵌套，达到加参数的目的kwargs={'name':str,'age':int}
    def wrapper(obj):#obj=People
        for key,val in kwargs.items():#(('name',str),('age',int))
            print(key,val)
            setattr(obj,key,Leixin(key,val))#定义描述符
           # setattr(People,'name',Leixin('name',str))
            #相当于People.name=Leixin('name',str)
        return obj
    return wrapper

@deco(name=str,age=int)#@wrapper>>>People=wrapper(People)
class People:
    def __init__(self,name,age,salary,gender,heigh):
        self.name=name

p1=People('s',12,222,'man',11)

print(People.__dict__)

>>>>

name <class 'str'>
age <class 'int'>
set方法 <__main__.People object at 0x100797e10> s
{'__module__': '__main__', '__init__': <function People.__init__ at 0x10079d268>, '__dict__': <attribute '__dict__' of 'People' objects>, '__weakref__': <attribute '__weakref__' of 'People' objects>, '__doc__': None, 'name': <__main__.Leixin object at 0x100797d68>, 'age': <__main__.Leixin object at 0x100797dd8>}