python 实现装饰器设计模式

python 装饰器简单、基本的实现并不复杂。装饰器（Decorators）模式类似于继承，当你需要为某一个对象添加额外的动作、行为时，在不改变类的情况下可以使用装饰器。这篇文就当做一篇水文，本来不想写，因为这个专栏是设计模式的多语言基本实现，不涉及过多内容，为了保证内容完整，所以只能直接塞进来了。

首先我们先新建一个人的基类，并且赋予几个属性（名字、性别、头发、衣服等），并且由两个基类，男人和女人：

class People():
    name = ""
    sex=""
    clothes = "没穿"
    hair="光头"
    sound_color=""

class Man(People):
    def __init__(self,name):
        self.name=name
        self.sex="男"
 
class Woman(People):
    def __init__(self,name):
        self.name=name
        self.sex="女"

由于类以及新建，不进行改变，使用装饰器进行行为状态添加，是用装饰器。新建一个装饰器基类，设置好装饰器方法，gethair 与 getclothes，再写两个类 hairDecorator与 dressedDecorator 继承于 exteriorDecorator，在装饰器 hairDecorator 中使对象长出头发，原有对象中头发的属性值是关头，在 dressedDecorator 中使对象穿上衣服，原有属性为没穿衣服。装饰器类如下：

class exteriorDecorator():#外形装饰基
    def gethair(self):
        pass
    def getclothes(self):
        pass
        
class hairDecorator(exteriorDecorator):#头发装饰
    def __init__(self,people):
        self.people=people
        self.sex="男"
    def gethair(self):
        return str(self.people.name)+" 长出头发"

class dressedDecorator(exteriorDecorator):#外衣装饰
    def __init__(self,people):
        self.people=people
        self.sex="男"
    def getclothes(self):
        return str(self.people.name)+" 穿上外衣"

以上装饰器在初始化时传入了类对象。接下来新建一个对象小明与装饰器对象：

xiaoming=Man("小明")
xiaomingHariD=hairDecorator(xiaoming)

使用hairDecorator 方法装饰小明的头发，使用 dressedDecorator 装饰小明的上衣：

xiaomingHariD=hairDecorator(xiaoming)
xiaomingdressedD=dressedDecorator(xiaoming)

最后进行输出：

print(xiaomingHariD.gethair())
print(xiaomingdressedD.getclothes())

结果如下：

完整代码如下：

class People():
    name = ""
    sex=""
    clothes = "没穿"
    hair="光头"
    sound_color=""

class Man(People):
    def __init__(self,name):
        self.name=name
        self.sex="男"
 
class Woman(People):
    def __init__(self,name):
        self.name=name
        self.sex="女" 


class exteriorDecorator():#外形装饰基
    def gethair(self):
        pass
    def getclothes(self):
        pass
        
class hairDecorator(exteriorDecorator):#头发装饰
    def __init__(self,people):
        self.people=people
        self.sex="男"
    def gethair(self):
        return str(self.people.name)+" 长出头发"

class dressedDecorator(exteriorDecorator):#外衣装饰
    def __init__(self,people):
        self.people=people
        self.sex="男"
    def getclothes(self):
        return str(self.people.name)+" 穿上外衣"

xiaoming=Man("小明")
print(xiaoming.name)
xiaomingHariD=hairDecorator(xiaoming)
xiaomingdressedD=dressedDecorator(xiaoming)
print(xiaomingHariD.gethair())
print(xiaomingdressedD.getclothes())