python——装饰器深入研究（三）

╰半夏微凉° 2024-04-07 13:49 72阅读 0赞

![在这里插入图片描述][37091b7857334286b05fb9a7f998f4bb.webp_pic_center]

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## 一、不带参数的装饰器 ##

### 1、案例1 ###

class Demo:
        pass
    
    @Demo
    def work():
        print('work开始工作')
    
    if __name__ == '__main__':
        work()

def work():  
TypeError: Demo() takes no arguments

> **第4、5行的代码的执行逻辑是：work=Demo(work)  
> 相当于初始化一个实例对象，需要定义参数去接收work，案例2**

### 2、案例2 ###

class Demo:
        def __init__(self,func):
            self.func=func
    
    @Demo
    def work():
        print('work开始工作')
    
    if __name__ == '__main__':
        work()

work()  
TypeError: ‘Demo’ object is not callable

> **实例化对象，不能调用，如果想要调用需要使用\_\_call\_\_()方法**

### 3、案例3 ###

class Demo:
        def __init__(self,func):
            self.func=func
    
        def __call__(self, *args, **kwargs):
            self.func()
    
    @Demo
    def work():
        print('work开始工作')
    
    if __name__ == '__main__':
        work()

work开始工作

## 二、带参数的装饰器 ##

### 方法1：采用闭包 ###

class Demo:
    
        def __init__(self,number):
            self.number=number
    
        def __call__(self,func, *args, **kwargs):
    
            def wrapper(*args,**kwargs):
                print('拓展功能1')
                res=func(*args,**kwargs)
                print('拓展功能2')
                return res
            return wrapper
    
    @Demo(number=24)
    def work(a,b):
        return a+b
    
    if __name__ == '__main__':
        print(work(1,2))

拓展功能1  
拓展功能2  
3

### 方法二：不采用闭包 ###

class Demo:
        def __init__(self,number):
            self.number=number
    
        def __call__(self, func):
            self.func=func
            return self.run
    
        def run(self,*args,**kwargs):
            print('拓展功能1')
            res=self.func(*args,**kwargs)
            print('拓展功能2')
            return res
    
    
    @Demo(number=12)            #work=Demo(number=12)(work(a,b))
    def work(a,b):
        return a+b
    if __name__ == '__main__':
        print(work(11,22))

拓展功能1  
拓展功能2  
33

## 三、将多个装饰器封装到一个类里面 ##

![在这里插入图片描述][165061657bd74ee39ab8f8fd84fb2058.png]

### 1、使用静态方法实现 ###

class Mytest:
    
        @staticmethod
        def test1(func):
    
            def wrapper(*args,**kwargs):
                print('拓展功能1')
                res=func(*args,**kwargs)
                print('拓展功能2')
                return res
            return wrapper
    
        @staticmethod
        def test2(func):
    
            def wrapper(*args,**kwargs):
                print('拓展功能1')
                res=func(*args,**kwargs)
                print('拓展功能2')
                return res
            return wrapper
    
    @Mytest.test1
    def work1(a,b):
        return a+b
    
    @Mytest.test2
    def work2(a,b):
        return a-b
    
    
    if __name__ == '__main__':
        print(work1(24,8))
        print(work2(24,8))

拓展功能1  
拓展功能2  
32  
拓展功能1  
拓展功能2  
16

### 2、使用类方法实现 ###

class Mytest:
    
        @classmethod
        def test1(cls,func):
    
            def wrapper(*args,**kwargs):
                print('拓展功能1')
                res=func(*args,**kwargs)
                print('拓展功能2')
                return res
            return wrapper
    
        @classmethod
        def test2(cls,func):
    
            def wrapper(*args,**kwargs):
                print('拓展功能1')
                res=func(*args,**kwargs)
                print('拓展功能2')
                return res
            return wrapper
    
    @Mytest.test1
    def work1(a,b):
        return a+b
    
    @Mytest.test2
    def work2(a,b):
        return a-b
    
    
    if __name__ == '__main__':
        print(work1(24,8))
        print(work2(24,8))

## 四、多个装饰器同时装饰一个函数的执行顺序 ##

test_datas = [{
        "title": "测试用例", "data": "data1", "res": 1}]
    
    @ddt
    class TestDemo:
    
        @unpack							test_demo=unpack(data(*test_datas)(test_demo))
        @data(*test_datas)				test_demo=data(*test_datas)(test_demo)
        def test_demo(self, item):
            print('执行测试用例')

### 执行顺序： ###

**`test_demo=unpack(data(*test_datas)(test_demo))`**

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![在这里插入图片描述][7f4f11c360314094a866169bbe4d6acd.png_pic_center]

[37091b7857334286b05fb9a7f998f4bb.webp_pic_center]: https://img-blog.csdnimg.cn/37091b7857334286b05fb9a7f998f4bb.webp#pic_center
[165061657bd74ee39ab8f8fd84fb2058.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/07/8f68b6d5506f481ab132c3bc7b87b956.png
[7f4f11c360314094a866169bbe4d6acd.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/07/0f87fe28644d4070bf30dd7d684167ce.png