我的Python環境：3.7

在Python類里聲明一個裝飾器，并在這個類里調用這個裝飾器。

代碼如下：

class Test(): xx = False def __init__(self): pass def test(func): def wrapper(self, *args, **kwargs): print(self.xx) return func(self, *args, **kwargs) return wrapper @test def test_a(self,a,b): print(f’ok,{a} {b}’)

注意：

1. 其中裝飾器test是在類Test中聲明并在其方法test_a中調用

2. 裝飾器test內層wrapper函數的首參數是self

補充知識：python-類內函數的全局裝飾器

有時，比如寫RF的測試庫的時候，很多方法都寫在一個類里。我們又可能需要一個通用的裝飾器，比如，要給某個底層類的方法打樁，查看入參和出參，用以理解業務；或者要hold住所有的執行錯誤，打印堆棧又不想程序退出或用例直接失敗

比如捕捉錯誤的裝飾器

import tracebackfrom functools import wrapsdef trier(soft=False): ’’’ :param bool soft: 為True時，打印報錯堆棧并忽略異常。默認False，打印報錯堆棧并拋出異常 :return: 如果要給類方法、靜態方法裝飾，則該裝飾器必須處于比@staticmethod裝飾器更內一層才行 ’’’ def realTrier(func): ’’’ :param function func: :return: ’’’ @wraps(func) # 保留__name__ __doc__ __module__ def innerfunc(*args, **kwargs): try:return func(*args, **kwargs) except Exception, e:try: print(traceback.format_exc())except: print eif not soft: raise return innerfunc return realTrier

或者參數跟蹤的裝飾器

def tracer(func): def infunc(*args, **kwargs): print func.__name__, args, kwargs res=infunc(*args, **kwargs) print func.__name__, res return res

這類裝飾器經常會給類里的每個函數都使用

每次都裝飾的話，也挺麻煩

python里可以給類寫個裝飾器，所以可以輸入一個類，返回一個新類，這個新類擁有原來類里的所有方法，但所有方法都被裝飾

使用元類，可以做到這一點。

目前可以批量裝飾普通方法、靜態方法、類方法、屬性，暫不支持__init__和__del__之類的特殊方法，以免出現意外的問題。

目前類B使用了全局裝飾器，假如類B繼承自類A，類C繼承自類B

則類B、類C內的所有方法都被全局裝飾（全局裝飾可以被繼承）

且類B繼承自類A的所有方法也會被全局裝飾

但這種裝飾不會影響到類A，調用類A下的方法時，所有方法都不被裝飾

經過多次嘗試，最后的實現代碼如下

# clswrapper.pydef skipper(func): ’’’ :param function func: :return: ’’’ func.__funskip__=True return funcdef classWrapper(commonDecoratorFunc): def innerMata(inClass): def collect_attrib(key, value, new_attrs): if hasattr(value, ’__funskip__’):new_attrs[key] = valuereturn if hasattr(value, ’__func__’) or isinstance(value, types.FunctionType):if isinstance(value, staticmethod): new_attrs[key] = staticmethod(commonDecoratorFunc(value.__func__)) returnelif isinstance(value, classmethod): new_attrs[key] = classmethod(commonDecoratorFunc(value.__func__)) returnelif not key.startswith(’__’): new_attrs[key] = commonDecoratorFunc(value) return else:if isinstance(value, property): # 當對property類進行重組的時候，我們強制裝飾了property類的fget fset和fdel方法。但是，不是每個propery都有這三個方法，有些是None，強制裝飾會報錯，所以我們這里要考慮提前返回None propertyWrapper = property(fget=commonDecoratorFunc(value.fget) if value.fget else None,fset=commonDecoratorFunc(value.fset) if value.fset else None,fdel=commonDecoratorFunc(value.fdel) if value.fdel else None,doc=value.__doc__) new_attrs[key] = propertyWrapper return new_attrs[key] = value class Meta(type): @classmethod def options(cls, bases, attrs):new_attrs = {}for key, value in attrs.items(): collect_attrib(key, value, new_attrs)for base in bases: for mbase in base.mro(): for key, value in mbase.__dict__.items(): if key not in new_attrs:collect_attrib(key, value, new_attrs)return new_attrs def __new__(cls, name, bases, attrs):new_attrs = cls.options(bases, attrs)return super(Meta, cls).__new__(cls, name, bases, new_attrs) return six.add_metaclass(Meta)(inClass) return innerMata

其中，skipper提供了一個后門，被skipper裝飾的函數會跳過全局裝飾器

使用方法如下

@classWrapper(trier(soft=True))class Tree(object): @skipper def div(self): return 1/0 def divsafe(self): return 1/0t=Tree()print t.divsafe()print t.div()

執行結果如圖

一個更完整的示例

from clswrapper那個文件 import skipper, classWrapperimport tracebackfrom functools import wraps’’’為簡潔起見，這次我們用的是不帶參數的trier裝飾器’’’def trier(func): @wraps(func) def inner(*args, **kwargs): try: return func(*args, **kwargs) except: print('EXCEPTION captured at function %s' % func.__name__, file=sys.stderr) print(traceback.format_exc().decode('gbk')) raise return innerif __name__=='__main__': import time class mobj(object): def five(self): w = 1 / 0 class obj(mobj): def __init__(self): # print 'obj.__init__' return @classmethod def one(self): w = 1 / 0 print(’obj.one’) @classWrapper(trier) # 或者用@classWrapper(argTrier(True))替換，則可以不拋出異常 class obj1(obj): aa = 1 def __init__(self): super(obj1, self).__init__() self.var = 1 @classmethod def three(cls): w = 1 / 0 print(’obj1.three’) @staticmethod def four(): w = 1 / 0 print(’obj1.four’) def two(self): w = 1 / 0 print(self.pro) print(’obj1.two’) @property def pro(self): return self.var @pro.setter def pro(self, value): self.var = value / 0 @skipper def eight(self): w=1/0 return w class outerobj(obj1): def seven(self): return 1/0 b = obj1() a = obj1 print(b.var) try: b.two() except: pass try: a.three() except: pass try: a.four() except: pass try: a.one() except: pass try: b.five() except: pass try: b.pro = 3 except: pass print(b.pro) print(a.aa) c=outerobj() try: c.five() except: pass try: c.seven() except: pass try: c.eight() except: print('c.eight被跳過，所以沒有被里層捕獲，才會不打堆棧直接走到這里') print('最后這個會真正觸發異常，因為mobj實例并沒有被裝飾過') m=mobj() time.sleep(1) m.five()

它展示了這個強大裝飾器能處理的各種情況，執行結果應該如下

1EXCEPTION captured at function twoEXCEPTION captured at function threeTraceback (most recent call last):EXCEPTION captured at function four File 'E:/pydev/異常處理裝飾器.py', line 37, in innerEXCEPTION captured at function one return func(*args, **kwargs)EXCEPTION captured at function five File 'E:/pydev/異常處理裝飾器.py', line 138, in two w = 1 / 0ZeroDivisionError: integer division or modulo by zeroTraceback (most recent call last): File 'E:/pydev/異常處理裝飾器.py', line 37, in inner return func(*args, **kwargs) File 'E:/pydev/異常處理裝飾器.py', line 129, in three w = 1 / 0ZeroDivisionError: integer division or modulo by zeroTraceback (most recent call last): File 'E:/pydev/異常處理裝飾器.py', line 37, in inner return func(*args, **kwargs) File 'E:/pydev/異常處理裝飾器.py', line 134, in four w = 1 / 0EXCEPTION captured at function proZeroDivisionError: integer division or modulo by zeroEXCEPTION captured at function fiveTraceback (most recent call last):EXCEPTION captured at function five File 'E:/pydev/異常處理裝飾器.py', line 37, in innerEXCEPTION captured at function seven return func(*args, **kwargs) File 'E:/pydev/異常處理裝飾器.py', line 115, in one w = 1 / 0ZeroDivisionError: integer division or modulo by zeroTraceback (most recent call last): File 'E:/pydev/異常處理裝飾器.py', line 37, in inner return func(*args, **kwargs) File 'E:/pydev/異常處理裝飾器.py', line 104, in five w = 1 / 0ZeroDivisionError: integer division or modulo by zeroTraceback (most recent call last): File 'E:/pydev/異常處理裝飾器.py', line 37, in inner return func(*args, **kwargs) File 'E:/pydev/異常處理裝飾器.py', line 148, in pro self.var = value / 0ZeroDivisionError: integer division or modulo by zero11Traceback (most recent call last): File 'E:/pydev/異常處理裝飾器.py', line 37, in inner return func(*args, **kwargs) File 'E:/pydev/異常處理裝飾器.py', line 104, in five w = 1 / 0ZeroDivisionError: integer division or modulo by zeroTraceback (most recent call last): File 'E:/pydev/異常處理裝飾器.py', line 37, in inner return func(*args, **kwargs) File 'E:/pydev/異常處理裝飾器.py', line 37, in inner return func(*args, **kwargs) File 'E:/pydev/異常處理裝飾器.py', line 104, in five w = 1 / 0ZeroDivisionError: integer division or modulo by zeroTraceback (most recent call last): File 'E:/pydev/異常處理裝飾器.py', line 37, in inner return func(*args, **kwargs) File 'E:/pydev/異常處理裝飾器.py', line 157, in seven return 1/0ZeroDivisionError: integer division or modulo by zeroc.eight被跳過，所以沒有被里層捕獲，才會不打堆棧直接走到這里最后這個會真正觸發異常，因為mobj實例并沒有被裝飾過Traceback (most recent call last): File 'E:/pydev/�쳣����װ����.py', line 212, in <module> m.five() File 'E:/pydev/�쳣����װ����.py', line 104, in five w = 1 / 0ZeroDivisionError: integer division or modulo by zero進程已結束，退出代碼 1

以上這篇Python類中的裝飾器在當前類中的聲明與調用詳解就是小編分享給大家的全部內容了，希望能給大家一個參考，也希望大家多多支持好吧啦網。