根据装饰器和被装饰对象的不同类型，装饰器的使用场景主要有以下情况
装饰器是函数，
被装饰对象也是函数
装饰器无参数，被装饰对象无参数装饰器无参数，被装饰对象有参数装饰器有参数，被装饰对象无参数装饰器有参数，被装饰器对象有参数 被装饰对象是类
装饰器无参数，被装饰类无参数装饰器无参数，被装饰类有参数装饰器有参数，被装饰类无参数装饰器有参数，被装饰类有参数 被装饰对象是类中的方法
装饰器无参数，被装饰类中的方法无参数装饰器无参数，被装饰类中的方法有参数装饰器有参数，被装饰类中的方法无参数装饰器有参数，被装饰类中的方法有参数 装饰器是类
被装饰对象也是函数
装饰器无参数，被装饰对象无参数装饰器无参数，被装饰对象有参数装饰器有参数，被装饰对象无参数装饰器有参数，被装饰器对象有参数 被装饰器对象是类
装饰器无参数，被装饰类无参数装饰器无参数，被装饰类有参数装饰器有参数，被装饰类无参数装饰器有参数，被装饰类有参数 被装饰对象是类中的方法
装饰器无参数，被装饰类中的方法无参数装饰器无参数，被装饰类中的方法有参数装饰器有参数，被装饰类中的方法无参数装饰器有参数，被装饰类中的方法有参数
实例演示不同场景下的装饰器
装饰器是函数，
被装饰对象也是函数 装饰器是函数，被装饰对象是函数时，此时装饰器的作用是给被装饰对象的函数做功能增强功能，思想是面向切面编程思想，即在被装饰对象的函数的之前和之后做一些额外处理，而不破坏被装饰函数原有的功能实现，主要有以下几种情况：
装饰器无参数，被装饰对象无参数def decorator(func):
def _decorator():
print("before func......")
func()
print("after func......")
return _decorator
@decorator
def func():
print("in func()......")
func()
执行结果为：before func......
in func()......
after func......
装饰器无参数，被装饰对象有参数def decorator(func):
def _decorator(*args,**kwargs):
print("before {name}......".format(name=func.__name__))
func(*args,**kwargs)
print("after {name}......".format(name=func.__name__))
return _decorator
@decorator
def func1():
print("in func1()......")
@decorator
def func2(a,b):
print("in func2()......")
print("a={a},b={b}".format(a=a,b=b))
@decorator
def func3(a,b,c=10):
print("in func3()......")
print("a={a},b={b}".format(a=a, b=b))
print("c={c}".format(c=c))
func1()
func2(1,2)
func3(1,2,c=100)
运行结果为：before func1......
in func1()......
after func1......
before func2......
in func2()......
a=1,b=2
after func2......
before func3......
in func3()......
a=1,b=2
c=100
after func3......
装饰器有参数，被装饰对象无参数def wrapper(name):
def decorator(func):
def _decorator():
print("before {name} ,decorator param is {param}".format(name=func.__name__,param=name))
print("before {name}......".format(name=func.__name__))
func()
print("after {name}......".format(name=func.__name__))
return _decorator
return decorator
@wrapper(name="hello world")
def func1():
print("in func1()......")
func1()
运行结果为：before func1 ,decorator param is hello world
before func1......
in func1()......
after func1......
装饰器有参数，被装饰器对象有参数def wrapper(name):
def decorator(func):
def _decorator(*args,**kwargs):
print("before {name} ,decorator param is {param}".format(name=func.__name__,param=name))
print("before {name}......".format(name=func.__name__))
func(*args,**kwargs)
print("after {name}......".format(name=func.__name__))
return _decorator
return decorator
@wrapper(name="hello world")
def func1():
print("in func1()......")
@wrapper(name="hello world")
def func2(a, b):
print("in func2()......")
print("a={a},b={b}".format(a=a, b=b))
@wrapper(name="hello world")
def func3(a, b, c=10):
print("in func3()......")
print("a={a},b={b}".format(a=a, b=b))
print("c={c}".format(c=c))
func1()
func2(1,2)
func3(1,2,c=100)
运行结果如下：before func1 ,decorator param is hello world
before func1......
in func1()......
after func1......
before func2 ,decorator param is hello world
before func2......
in func2()......
a=1,b=2
after func2......
before func3 ,decorator param is hello world
before func3......
in func3()......
a=1,b=2
c=100
after func3......
被装饰器对象是类 被装饰器对象为类时，装饰器的作用是类在初始化的时候做功能增强，即可以在类初始化之前或者之后做一些功能增强，所以下面所说的被装饰对象有无参数是针对类的初始化函数__init__有无参数而言的，主要有以下几种情况：
装饰器无参数，被装饰类无参数def decorator(cls):
def _decorator():
print("before class {name} init......".format(name=cls.__name__))
obj=cls()
print("after class {name} init......".format(name=cls.__name__))
return obj
return _decorator
@decorator
class Test(object):
def __init__(self):
print("in class {name} init function......".format(name=Test.__name__))
def func(self):
print("in class {name} func()".format(name=Test.__name__))
test=Test()
test.func()
运行结果如下：before class Test init......
in class _decorator init function......
after class Test init......
in class _decorator func()
装饰器无参数，被装饰类有参数def decorator(cls):
def _decorator(*args,**kwargs):
print("before class {name} init......".format(name=cls.__name__))
obj=cls(*args,**kwargs)
print("after class {name} init......".format(name=cls.__name__))
return obj
return _decorator
@decorator
class Test(object):
def __init__(self,a,b=10):
print("in class {name} init function......".format(name=Test.__name__))
print("a={a},b={b}".format(a=a,b=b))
def func(self):
print("in class {name} func()".format(name=Test.__name__))
test=Test(2,20)
test.func()
执行结果如下：before class Test init......
in class _decorator init function......
a=2,b=20
after class Test init......
in class _decorator func()
装饰器有参数，被装饰类无参数def wrapper(name="hello world"):
def decorator(cls):
def _decorator():
print("before class {name} init......".format(name=cls.__name__))
obj=cls()
print("after class {name} init......".format(name=cls.__name__))
return obj
return _decorator
return decorator
@wrapper("hello world")
class Test(object):
def __init__(self):
print("in class {name} init function......".format(name=Test.__name__))
def func(self):
print("in class {name} func()".format(name=Test.__name__))
test=Test()
test.func()
执行结果如下：before class Test init......
in class _decorator init function......
after class Test init......
in class _decorator func()
装饰器有参数，被装饰类有参数def wrapper(name="hello world"):
def decorator(cls):
def _decorator(*args,**kwargs):
print("before class {name} init......".format(name=cls.__name__))
obj=cls(*args,**kwargs)
print("after class {name} init......".format(name=cls.__name__))
return obj
return _decorator
return decorator
@wrapper("hello world")
class Test(object):
def __init__(self,a,b=10):
print("in class {name} init function......".format(name=Test.__name__))
print("a= {a} b={b}".format(a=a,b=b))
def func(self):
print("in class {name} func()".format(name=Test.__name__))
test=Test(2,b=20)
test.func()
运行结果如下：before class Test init......
in class _decorator init function......
a= 2 b=20
after class Test init......
in class _decorator func()
被装饰对象是类中的方法
装饰器无参数，被装饰类中的方法无参数def decorator(func):
def _decorator(self):
print("before class {name} init......".format(name=func.__name__))
obj=func(self)
print("after class {name} init......".format(name=func.__name__))
return obj
return _decorator
class Test(object):
def __init__(self,a=1,b=10):
self.a=a
self.b=b
@decorator
def func(self):
print("in class {name} func()".format(name=Test.__name__))
print("a={a} b={b}".format(a=self.a,b=self.b))
test=Test()
test.func()
执行结果如下：before class func init......
in class Test func()
a=1 b=10
after class func init......
装饰器无参数，被装饰类中的方法有参数
def decorator(func):
def _decorator(self,*args,**kwargs):
print("before class {name} init......".format(name=func.__name__))
obj=func(self,*args,**kwargs)
print("after class {name} init......".format(name=func.__name__))
return obj
return _decorator
class Test(object):
def __init__(self,a=1,b=10):
self.a=a
self.b=b
@decorator
def func(self,c,d=20):
print("in class {name} func()".format(name=Test.__name__))
print("a={a} b={b}".format(a=self.a,b=self.b))
print("c={c} d={d}".format(c=c,d=d))
test=Test()
test.func(2,d=20)
执行结果如下：before class func init......
in class Test func()
a=1 b=10
c=2 d=20
after class func init......
装饰器有参数，被装饰类中的方法无参数
def wrapper(name="hello world"):
def decorator(func):
def _decorator(self):
print("before class {name} init......".format(name=func.__name__))
print("name = {name}".format(name=name))
obj=func(self)
print("after class {name} init......".format(name=func.__name__))
return obj
return _decorator
return decorator
class Test(object):
def __init__(self,a=1,b=10):
self.a=a
self.b=b
@wrapper(name="Test.func")
def func(self):
print("in class {name} func()".format(name=Test.__name__))
print("a={a} b={b}".format(a=self.a,b=self.b))
test=Test()
test.func()
执行结果如下：before class func init......
name = Test.func
in class Test func()
a=1 b=10
after class func init......
装饰器有参数，被装饰类中的方法有参数def wrapper(name="hello world"):
def decorator(func):
def _decorator(self,*args,**kwargs):
print("before class {name} init......".format(name=func.__name__))
print("name = {name}".format(name=name))
obj=func(self,*args,**kwargs)
print("after class {name} init......".format(name=func.__name__))
return obj
return _decorator
return decorator
class Test(object):
def __init__(self,a=1,b=10):
self.a=a
self.b=b
@wrapper(name="Test.func")
def func(self,c,d=20):
print("in class {name} func()".format(name=Test.__name__))
print("a={a} b={b}".format(a=self.a,b=self.b))
print("c={c} d={d}".format(c=c,d=d))
test=Test()
test.func(2,d=20)
执行结果如下：before class func init......
name = Test.func
in class Test func()
a=1 b=10
c=2 d=20
after class func init......
装饰器是类
被装饰对象是函数 装饰器是类，被装饰对象是函数的时候，是通过装饰器类初始化的时候将被装饰对象函数传递给装饰器类，然后通过自动调用装饰器类中的__call__函数实现对被装饰对象的前后处理，即在这种情况下，只需要在__call__函数中编写在调用被装饰对象前后进行操作的代码即可
装饰器无参数，被装饰对象无参数class decorator(object):
def __init__(self,func):
self.func=func
def __call__(self):
print("before func {func}()...".format(func=self.func.__name__))
result=self.func()
print("after func {func}()...".format(func=self.func.__name__))
return result
@decorator
def func():
print("in func func()...")
func()
执行结果如下：before func func()...
in func func()...
after func func()...
装饰器无参数，被装饰对象有参数class decorator(object):
def __init__(self,func):
self.func=func
def __call__(self,*args,**kwargs):
print("before func {func}()...".format(func=self.func.__name__))
result=self.func(*args,**kwargs)
print("after func {func}()...".format(func=self.func.__name__))
return result
@decorator
def func(a,b=10):
print("in func func()...")
print("a= {a} b={b}".format(a=a,b=b))
func(2,b=20)
执行结果如下：before func func()...
in func func()...
a= 2 b=20
after func func()...
装饰器有参数，被装饰对象无参数
class decorator(object):
def __init__(self,name="hello world"):
self.name=name
def __call__(self,func):
def wrapper():
print("before func {func}()...".format(func=func.__name__))
print("name= {name}".format(name=self.name))
result=func()
print("after func {func}()...".format(func=func.__name__))
return result
return wrapper
@decorator()
def func1():
print("in func func2()...")
@decorator("func2_decorator")
def func2():
print("in func func2()...")
@decorator(name="func3_decorator")
def func3():
print("in func func3()...")
func1()
func2()
func3()
执行结果如下：before func func1()...
name= hello world
in func func2()...
after func func1()...
before func func2()...
name= func2_decorator
in func func2()...
after func func2()...
before func func3()...
name= func3_decorator
in func func3()...
after func func3()...
装饰器有参数，被装饰器对象有参数
class decorator(object):
def __init__(self,name="hello world"):
self.name=name
def __call__(self,func):
def wrapper(*args,**kwargs):
print("before func {func}()...".format(func=func.__name__))
print("name= {name}".format(name=self.name))
result=func(*args,**kwargs)
print("after func {func}()...".format(func=func.__name__))
return result
return wrapper
@decorator()
def func1():
print("in func func2()...")
@decorator("func2_decorator")
def func2(a):
print("in func func2()...")
print("a={a}".format(a=a))
@decorator(name="func3_decorator")
def func3(a,b=10):
print("in func func3()...")
print("a={a}, b= {b}".format(a=a,b=b))
func1()
func2(10)
func3(2,b=20)
执行结果如下：before func func1()...
name= hello world
in func func2()...
after func func1()...
before func func2()...
name= func2_decorator
in func func2()...
a=10
after func func2()...
before func func3()...
name= func3_decorator
in func func3()...
a=2, b= 20
after func func3()...
被装饰器对象是类
装饰器无参数，被装饰类无参数class decorator(object):
def __init__(self,cls):
self.cls=cls
def __call__(self):
print("before init clsss {cls}...".format(cls=self.cls.__name__))
obj=self.cls()
print("after init class {cls}...".format(cls=self.cls.__name__))
return obj
@decorator
class Test():
def __init__(self):
print("in Test class __init__ func...")
def test(self):
print("in Test class test func...")
t=Test()
t.test()
执行结果如下：before init clsss Test...
in Test class __init__ func...
after init class Test...
in Test class test func...
装饰器无参数，被装饰类有参数class decorator(object):
def __init__(self,cls):
self.cls=cls
def __call__(self,*args,**kwargs):
print("before init clsss {cls}...".format(cls=self.cls.__name__))
obj=self.cls(*args,**kwargs)
print("after init class {cls}...".format(cls=self.cls.__name__))
return obj
@decorator
class Test():
def __init__(self,a,b=10):
print("in Test class __init__ func...")
print("a={a} b={b}".format(a=a,b=b))
def test(self):
print("in Test class test func...")
t=Test(2,b=20)
t.test()
执行结果如下：before init clsss Test...
in Test class __init__ func...
a=2 b=20
after init class Test...
in Test class test func...
装饰器有参数，被装饰类无参数class decorator(object):
def __init__(self,name="hello world"):
self.name=name
def __call__(self,cls):
def wrapper():
print("before init class {cls}....".format(cls=cls.__name__))
obj=cls()
print("after init class {cls}...".format(cls=cls.__name__))
return obj
return wrapper
@decorator(name="Test Class")
class Test():
def __init__(self):
print("in Test class __init__ func...")
def test(self):
print("in Test class test func...")
t=Test()
t.test()
执行结果如下：before init class Test....
in Test class __init__ func...
after init class Test...
in Test class test func...
装饰器有参数，被装饰类有参数class decorator(object):
def __init__(self,name="hello world"):
self.name=name
def __call__(self,cls):
def wrapper(*args,**kwargs):
print("before init class {cls}....".format(cls=cls.__name__))
obj=cls(*args,**kwargs)
print("after init class {cls}...".format(cls=cls.__name__))
return obj
return wrapper
@decorator(name="Test Class")
class Test():
def __init__(self,a,b=10):
print("in Test class __init__ func...")
print("a={a}, b={b}".format(a=a,b=b))
def test(self):
print("in Test class test func...")
t=Test(2,b=20)
t.test()
执行结果如下：before init class Test....
in Test class __init__ func...
a=2, b=20
after init class Test...
in Test class test func...
被装饰对象是类中的方法
装饰器无参数，被装饰类中的方法无参数class decorator(object):
def __init__(self,func):
self.func=func
def __call__(self):
print("before func {func}...".format(func=self.func.__name__))
results=self.func(self)
print("after func {func}...".format(func=self.func.__name__))
return results
class Test():
def __init__(self):
print("in Test class __init__ func...")
@decorator
def test(self):
print("in Test class test func...")
t=Test()
t.test()
执行结果如下：in Test class __init__ func...
before func test...
in Test class test func...
after func test...
装饰器无参数，被装饰类中的方法有参数class decorator(object):
def __init__(self,func):
self.func=func
def __call__(self,*args,**kwargs):
print("before func {func}...".format(func=self.func.__name__))
results=self.func(self,*args,**kwargs)
print("after func {func}...".format(func=self.func.__name__))
return results
class Test():
def __init__(self):
print("in Test class __init__ func...")
@decorator
def test(self,a,b=10):
print("in Test class test func...")
print("a={a} b={b}".format(a=a,b=b))
t=Test()
t.test(2,b=20)
执行结果如下：in Test class __init__ func...
before func test...
in Test class test func...
a=2 b=20
after func test...
装饰器有参数，被装饰类中的方法无参数class decorator(object):
def __init__(self,name="hello world"):
self.name=name
def __call__(self,func):
def wrapper(self):
print("before func {func}...".format(func=func.__name__))
results=func(self)
print("after func {func}...".format(func=func.__name__))
return results
return wrapper
class Test():
def __init__(self):
print("in Test class __init__ func...")
@decorator(name="Test_test")
def test(self):
print("in Test class test func...")
t=Test()
t.test()
执行结果如下：in Test class __init__ func...
before func test...
in Test class test func...
after func test...
装饰器有参数，被装饰类中的方法有参数class decorator(object):
def __init__(self,name="hello world"):
self.name=name
def __call__(self,func):
def wrapper(self,*args,**kwargs):
print("before func {func}...".format(func=func.__name__))
results=func(self,*args,**kwargs)
print("after func {func}...".format(func=func.__name__))
return results
return wrapper
class Test():
def __init__(self):
print("in Test class __init__ func...")
@decorator(name="Test_test")
def test(self,a,b=10):
print("in Test class test func...")
print("a={a}, b={b}".format(a=a,b=b))
t=Test()
t.test(2,b=20)
执行结果如下：in Test class __init__ func...
before func test...
in Test class test func...
a=2, b=20
after func test...
原文链接
