第六步：对参数数量不确定的函数进行装饰
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | # -*- coding:gbk -*-'''示例6: 对参数数量不确定的函数进行装饰，参数用(*args, **kwargs)，自动适应变参和命名参数'''def deco(func): def _deco(*args, **kwargs): print("before %s called." % func.__name__) ret = func(*args, **kwargs) print(" after %s called. result: %s" % (func.__name__, ret)) return ret return _deco@decodef myfunc(a, b): print(" myfunc(%s,%s) called." % (a, b)) return a+b@decodef myfunc2(a, b, c): print(" myfunc2(%s,%s,%s) called." % (a, b, c)) return a+b+cmyfunc(1, 2)myfunc(3, 4)myfunc2(1, 2, 3)myfunc2(3, 4, 5) |
第七步：让装饰器带参数
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | # -*- coding:gbk -*-'''示例7: 在示例4的基础上，让装饰器带参数，和上一示例相比在外层多了一层包装。装饰函数名实际上应更有意义些'''def deco(arg): def _deco(func): def __deco(): print("before %s called [%s]." % (func.__name__, arg)) func() print(" after %s called [%s]." % (func.__name__, arg)) return __deco return _deco@deco("mymodule")def myfunc(): print(" myfunc() called.")@deco("module2")def myfunc2(): print(" myfunc2() called.")myfunc()myfunc2() |
第八步：让装饰器带 类 参数
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | # -*- coding:gbk -*-'''示例8: 装饰器带类参数'''class locker: def __init__(self): print("locker.__init__() should be not called.") @staticmethod def acquire(): print("locker.acquire() called.（这是静态方法）") @staticmethod def release(): print(" locker.release() called.（不需要对象实例）")def deco(cls): '''cls 必须实现acquire和release静态方法''' def _deco(func): def __deco(): print("before %s called [%s]." % (func.__name__, cls)) cls.acquire() try: return func() finally: cls.release() return __deco return _deco@deco(locker)def myfunc(): print(" myfunc() called.")myfunc()myfunc() |
第九步：装饰器带类参数，并分拆公共类到其他py文件中，同时演示了对一个函数应用多个装饰器
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | # -*- coding:gbk -*-'''mylocker.py: 公共类 for 示例9.py'''class mylocker: def __init__(self): print("mylocker.__init__() called.") @staticmethod def acquire(): print("mylocker.acquire() called.") @staticmethod def unlock(): print(" mylocker.unlock() called.")class lockerex(mylocker): @staticmethod def acquire(): print("lockerex.acquire() called.") @staticmethod def unlock(): print(" lockerex.unlock() called.")def lockhelper(cls): '''cls 必须实现acquire和release静态方法''' def _deco(func): def __deco(*args, **kwargs): print("before %s called." % func.__name__) cls.acquire() try: return func(*args, **kwargs) finally: cls.unlock() return __deco return _deco |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | # -*- coding:gbk -*-'''示例9: 装饰器带类参数，并分拆公共类到其他py文件中同时演示了对一个函数应用多个装饰器'''from mylocker import *class example: @lockhelper(mylocker) def myfunc(self): print(" myfunc() called.") @lockhelper(mylocker) @lockhelper(lockerex) def myfunc2(self, a, b): print(" myfunc2() called.") return a + bif __name__=="__main__": a = example() a.myfunc() print(a.myfunc()) print(a.myfunc2(1, 2)) print(a.myfunc2(3, 4)) |
下面是参考资料，当初有不少地方没看明白，真正练习后才明白些：
1. Python装饰器学习 http://blog.csdn.net/thy38/article/details/4471421
2. Python装饰器与面向切面编程 http://www.cnblogs.com/huxi/archive/2011/03/01/1967600.html
3. Python装饰器的理解 http://apps.hi.baidu.com/share/detail/17572338
import functools
def lockhelper(cls):
def _deco(func):
@functools.wraps(func)
def __deco(*args, **kwargs):
2、以上例子都是对每个函数单独进行包装，在待包装函数之前都有一个@，是否可以不在每个函数前都加修饰呢？下面这篇博文的末尾处介绍了一种自动遍历类的每个方法，自动为每个方法添加装饰：
http://blog.csdn.net/zylcf818/article/details/5342276