你不能。类主体中没有self，因为不存在实例。您需要向它传递一个包含属性名称的str，以便在实例上进行查找，然后由返回的函数执行，或者使用完全不同的方法。

拥有一个通用实用程序将非常有用，它可以将函数的任何装饰器转换为方法的装饰器。我想了一个小时，终于想出了一个:

from typing import Callable
Decorator = Callable[[Callable], Callable]

def decorate_method(dec_for_function: Decorator) -> Decorator:

    def dec_for_method(unbounded_method) -> Callable:
        # here, `unbounded_method` will be a unbounded function, whose
        # invokation must have its first arg as a valid `self`. When it 
        # return, it also must return an unbounded method.
        def decorated_unbounded_method(self, *args, **kwargs):
            @dec_for_function
            def bounded_method(*args, **kwargs):
                return unbounded_method(self, *args, **kwargs)
            return bounded_method(*args, **kwargs)

        return decorated_unbounded_method

    return dec_for_method

用法是:

# for any decorator (with or without arguments)
@some_decorator_with_arguments(1, 2, 3)
def xyz(...): ...

# use it on a method:
class ABC:
  @decorate_method(some_decorator_with_arguments(1, 2, 3))
  def xyz(self, ...): ...

测试:

def dec_for_add(fn):
    """This decorator expects a function: (x,y) -> int.

    If you use it on a method (self, x, y) -> int, it will fail at runtime.
    """
    print(f"decorating: {fn}")
    def add_fn(x,y):
        print(f"Adding {x} + {y} by using {fn}")
        return fn(x,y)
    return add_fn


@dec_for_add
def add(x,y):
    return x+y

add(1,2)  # OK!


class A:
    @dec_for_add
    def f(self, x, y):
        # ensure `self` is still a valid instance
        assert isinstance(self, A)
        return x+y

# TypeError: add_fn() takes 2 positional arguments but 3 were given
# A().f(1,2)
    

class A:
    @decorate_method(dec_for_add)
    def f(self, x, y):
        # ensure `self` is still a valid instance
        assert isinstance(self, A)
        return x+y

# Now works!!
A().f(1,2)

from re import search
from functools import wraps

def is_match(_lambda, pattern):
    def wrapper(f):
        @wraps(f)
        def wrapped(self, *f_args, **f_kwargs):
            if callable(_lambda) and search(pattern, (_lambda(self) or '')): 
                f(self, *f_args, **f_kwargs)
        return wrapped
    return wrapper

class MyTest(object):

    def __init__(self):
        self.name = 'foo'
        self.surname = 'bar'

    @is_match(lambda x: x.name, 'foo')
    @is_match(lambda x: x.surname, 'foo')
    def my_rule(self):
        print 'my_rule : ok'

    @is_match(lambda x: x.name, 'foo')
    @is_match(lambda x: x.surname, 'bar')
    def my_rule2(self):
        print 'my_rule2 : ok'



test = MyTest()
test.my_rule()
test.my_rule2()

输出: My_rule2:好的

一个更简洁的例子如下:

#/usr/bin/env python3
from functools import wraps

def wrapper(method):
    @wraps(method)
    def _impl(self, *method_args, **method_kwargs):
        method_output = method(self, *method_args, **method_kwargs)
        return method_output + "!"
    return _impl

class Foo:
    @wrapper
    def bar(self, word):
        return word

f = Foo()
result = f.bar("kitty")
print(result)

这将打印:

kitty!

是的。不是在类定义时传入实例属性，而是在运行时检查它:

def check_authorization(f):
    def wrapper(*args):
        print args[0].url
        return f(*args)
    return wrapper

class Client(object):
    def __init__(self, url):
        self.url = url

    @check_authorization
    def get(self):
        print 'get'

>>> Client('http://www.google.com').get()
http://www.google.com
get

装饰器截取方法参数;第一个参数是实例，因此它从实例中读取属性。如果你不想硬编码属性名，你可以将属性名作为字符串传递给装饰器，并使用getattr:

def check_authorization(attribute):
    def _check_authorization(f):
        def wrapper(self, *args):
            print getattr(self, attribute)
            return f(self, *args)
        return wrapper
    return _check_authorization

另一种选择是放弃语法糖，并在类的__init__中进行装饰。

def countdown(number):
    def countdown_decorator(func):
        def func_wrapper():
            for index in reversed(range(1, number+1)):
                print(index)
            func()
        return func_wrapper
    return countdown_decorator

class MySuperClass():
    def __init__(self, number):
        self.number = number
        self.do_thing = countdown(number)(self.do_thing)
    
    def do_thing(self):
        print('im doing stuff!')


myclass = MySuperClass(3)

myclass.do_thing()

它会打印

3
2
1
im doing stuff!