python 装饰器之自定义装饰器
一 装饰器的原理及作用
原理：闭包的使用
作用：在不改变原有函数代码的前提下，为函数增添功能
二 函数作为装饰器
无参装饰器，被修饰的是普通函数
from functools import wraps
def ourter(func):
@wraps(func)
def inner(*args, **kwargs):
return func(*args, **kwargs)
return inner
@ourter
def test(name):
print(f'测试无参数的装饰器 {name}')
test('大番茄')
print(test.__name__)
## 输出结果
# 测试无参数的装饰器 大番茄
# test
无参装饰，被修饰的是类
from functools import wraps
def outer(cls):
cls.num = 10
print(cls)
return cls
@outer
class animal:
def __init__(self, name) -> None:
self.name = name
a = animal(name='zhangsan')
print(a.num)
print(a.name)
##输出结果
# 无参装饰器，被修饰的是类中的方法
from functools import wraps
def outer(func):
@wraps(func)
def inner(self, *args, **kwargs):
func(self, *args, **kwargs)
return inner
class animal:
def __init__(self, name):
self.name = name
@outer
def say(self):
print(f'我叫 {self.name}')
a = animal(name='zhangsan')
a.say()
print(a.say.__name__)
## 输出结果
# 我叫 zhangsan
# say
有参装饰器，被修饰的是普通函数
from functools import wraps
def newouter(*args, **kwargs):
print('获取装饰器中的参数')
print(args)
print(kwargs)
def ourter(func):
@wraps(func)
def inner(*args, **kwargs):
return func(*args, **kwargs)
return inner
return ourter
@newouter(name='zhangsan', age=12)
def test(name):
print(f'测试无参数的装饰器 {name}')
test('大番茄')
print(test.__name__)
## 输出结果
# 获取装饰器中的参数
# ()
# {'name': 'zhangsan', 'age': 12}
# 测试无参数的装饰器 大番茄
# test
有参装饰器，被修饰的是类
from functools import wraps
def newouter(*args, **kwargs):
print('获取装饰器参数')
print(args)
print(kwargs)
def outer(cls):
cls.num = 10
print(cls)
return cls
return outer
@newouter(is_true=True, is_false=False)
class animal:
def __init__(self, name) -> None:
self.name = name
a = animal(name='zhangsan')
print(a.num)
print(a.name)
## 输出结果
# 获取装饰器参数
# ()
# {'is_true': True, 'is_false': False}
# 有参装饰器，被修饰的是类中的方法
from functools import wraps
def title(name):
def outer(func):
@wraps(func)
def inner(self, *args, **kwargs):
print(name)
func(self, *args, **kwargs)
return inner
return outer
class animal:
def __init__(self, name) -> None:
self.name = name
@title('开口说话')
def say(self):
print(f'我叫 {self.name}')
a = animal(name='zhangsan')
a.say()
print(a.say.__name__)
## 输出结果
# 开口说话
# 我叫 zhangsan
# say
三 类中的方法作为装饰器
class TestDeracotorClasss:
def deracotor_1(self, func):
def inner(*args, **kwargs):
print('装饰1开始')
func(*args, **kwargs)
print('装饰1结束')
print('--------------------------')
return inner
def derancotor_2(func):
def inner(self, *args, **kwargs):
print('装饰2开启')
func(self, *args, **kwargs)
print('装饰2关闭')
print('--------------------------')
return inner
@staticmethod
def derancotor_3(func):
def inner(self, *args, **kwargs):
print('开始装饰3')
func(self, *args, **kwargs)
print('结束装饰3')
print('--------------------------')
return inner
@classmethod
def derancotor_4(slc, func):
def inner(self, *args, **kwargs):
print('开始装饰4')
func(self, *args, **kwargs)
print('结束装饰4')
return inner
c = TestDeracotorClasss()
class Student:
@c.deracotor_1 # 使用类中的实例方法装饰
def test_1(self):
print('我是测试1')
@TestDeracotorClasss.derancotor_2
def test_2(self):
print('我是测试2')
@TestDeracotorClasss.derancotor_3
def test_3(self):
print('我是测试3')
@TestDeracotorClasss.derancotor_4
def test_4(self):
print('我是测试4')
s = Student()
s.test_1()
s.test_2()
s.test_3()
s.test_4()
## 输出结果
# 装饰1开始
# 我是测试1
# 装饰1结束
# --------------------------
# 装饰2开启
# 我是测试2
# 装饰2关闭
# --------------------------
# 开始装饰3
# 我是测试3
# 结束装饰3
# --------------------------
# 开始装饰4
# 我是测试4
# 结束装饰4
四 类作为装饰器
无参装饰器，被修饰的是普通函数
from functools import wraps
class animal:
def __call__(self, func):
@wraps(func)
def wrapped_function(*args, **kwargs):
return func(*args, **kwargs)
return wrapped_function
@animal()
def test(name, kind):
print(f'{name} belongs to {kind}')
A = test('cow','mammals')
print(test.__name__)
## 输出结果
# cow belongs to mammals
# test
无参装饰器，被修饰的是类
class animal:
def __init__(self, func):
self.func = func
print(self.func)
def __call__(self, *args, **kwds):
return self.func(*args, **kwds)
@animal
class cat:
def test_1(self):
print('running')
c = cat()
c.test_1()
## 输出结果
# 无参装饰器，被修饰的是类中的方法
class animal:
def __init__(self, func):
self.func = func
print(self.func)
def __call__(self, *args, **kwds):
return self.func(self, *args, **kwds)
class cat:
@animal
def test_1(self):
print('running')
c = cat()
c.test_1()
## 输出结果
# 有参装饰器，被修饰的是普通函数
from functools import wraps
class animal:
def __init__(self, *args, **kwargs):
print('获取参数')
print(args)
print(kwargs)
def __call__(self, func):
@wraps(func)
def wrapped_function(*args, **kwargs):
print('working here')
return func(*args, **kwargs)
return wrapped_function
@animal(is_true=True)
def test(name, kind):
word = f'{name} belongs to {kind}'
return word
A = test('cow','mammals')
print(test.__name__)
## 输出结果
# 获取参数
# ()
# {'is_true': True}
# working here
# test
有参装饰器，被修饰的是类
from functools import wraps
class animal:
def __init__(self, *args, **kwargs):
print('获取参数')
print(args)
print(kwargs)
def __call__(self, func):
@wraps(func)
def inner(*args, **kwds):
return func(*args, **kwds)
return inner
@animal(is_true=True)
class cat:
def test_1(self):
print('running')
c = cat()
c.test_1()
print(c.test_1.__name__)
## 输出结果
# 获取参数
# ()
# {'is_true': True}
# running
# test_1
有参装饰器，被修饰的是类中的方法
class animal:
def __init__(self, *args, **kwargs):
print('获取参数')
print(args)
print(kwargs)
def __call__(self, func):
def inner(*args, **kwds):
return func(*args, **kwds)
return inner
class cat:
@animal(is_true=True)
def test_1(self):
print('running')
c = cat()
c.test_1()
## 输出结果
# 获取参数
# ()
# {'is_true': True}
# running