python 装饰器的使用示例

无参修饰 ,无参数时不需要调用

def log1(func): func()@log1def test(): print(’test:’)

有参修饰

def log2(func): def inner(*args, **kwargs): func(*args, **kwargs) return inner@log2def test(num): print(’testlog2:’,num,test.__name__)test(20) #相当于log(test(20))

@wraps可以保证装饰器修饰的函数的name的值保持不变

不带参数的装饰器

def log3(func): @wraps(func) def inner(*args, **kwargs,): func(*args, **kwargs) return inner@log3def test(num): print(’testlog3:’,num,test.__name__)test(30) #相当于log(test(30))

带参数的装饰器

def log4(level): def log(func): @wraps(func) def inner(*args, **kwargs,): if level == 'warn':print('%s is running' % func.__name__) func(*args, **kwargs) return inner return log@log4(level='warn')def test(num): print(’testlog4:’, num, test.__name__)test(40)

实现带参数和不带参数的装饰器自适应

def log(arg): if callable(arg): # 判断参入的参数是否是函数，不带参数的装饰器调用这个分支 def log3(func): @wraps(func) def inner(*args, **kwargs, ):func(*args, **kwargs) return inner return log3 else: def log4(func): @wraps(func) def inner(*args, **kwargs,):if arg == 'warn': print('%s is running' % func.__name__)func(*args, **kwargs) return inner return log4@log(arg=None)def test(num): print(’testlog:’, num, test.__name__)test(0)

返回入参出参

def log5(func): def inner(*args, **kwargs): print(’入参：’,func.__name__, args, kwargs) res =func(*args, **kwargs) print(’出参：’,func.__name__, res) return res return inner@log5def test(num): print(’testlog5:’, num, test.__name__) return numprint(test(50))

类装饰器

class Loging: def __init__(self,level): self.level = level def __call__(self,func): @wraps(func) def inner(*args, **kwargs): if self.level == 'warn':self.notify(func) func(*args, **kwargs) return inner def notify(self,func): print ('%s is running' % func.__name__)@Loging(level='warn')def test(num): print(’testLoging:’, num, test.__name__)test(0)

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