本文实例讲述了Python装饰器用法。分享给大家供大家参考，具体如下：
用类作为装饰器
示例一
最初代码：
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class bol(object): def __init__(self, func): self.func = func def __call__(self): return "<b>{}</b>".format(self.func())class ita(object): def __init__(self, func): self.func = func def __call__(self): return "<i>{}</i>".format(self.func())@bol@itadef sayhi(): return 'hi' |
改进一：
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class sty(object): def __init__(self, tag): self.tag = tag def __call__(self, f): def wraper(): return "<{tag}>{res}</{tag}>".format(res=f(), tag=self.tag) return wraper@sty('b')@sty('i')def sayhi(): return 'hi' |
改进二：
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class sty(object): def __init__(self, *tags): self.tags = tags def __call__(self, f): def wraper(): n = len(self.tags) return "{0}{1}{2}".format(('<{}>'*n).format(*self.tags), f(), ('</{}>'*n).format(*reversed(self.tags))) return wraper@sty('b', 'i')def sayhi(): return 'hi'print(sayhi()) |
改进三：
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class sty(object): def __init__(self, *tags): self.tags = tags def __call__(self, f): def wraper(*args, **kwargs): n = len(self.tags) return "{0}{1}{2}".format(('<{}>'*n).format(*self.tags), f(*args, **kwargs), ('</{}>'*n).format(*reversed(self.tags))) return wraper@sty('b', 'i')def say(word='Hi'): return wordprint(say())print(say('Hello')) |
示例二
最初代码：
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import threadingimport timeclass DecoratorClass(object): def __init__(self): self.thread = None def __call__(self, func, *args, **kwargs): def wrapped_func(*args, **kwargs): curr_thread = threading.currentThread().getName() self.thread = curr_thread print('\nthread name before running func:', self.thread) ret_val = func() print('\nthread name after running func:', self.thread) return ret_val return wrapped_func@DecoratorClass()def decorated_with_class(): print('running decorated w class') time.sleep(1) returnthreads = []for i in range(5): t = threading.Thread(target=decorated_with_class) threads.append(t) t.setDaemon(True) # 守护 t.start() |
改进：进程锁
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import threadingimport timeclass DecoratorClass(object): def __init__(self): self.thread = None self.lock = threading.Lock() def __call__(self, func, *args, **kwargs): def wrapped_func(*args, **kwargs): self.lock.acquire() curr_thread = threading.currentThread().getName() self.thread = curr_thread print('thread name before running func:', self.thread) ret_val = func() print('\nthread name after running func:', self.thread) self.lock.release() return ret_val return wrapped_func@DecoratorClass()def decorated_with_class(): print('Let me sleep 1 second...') time.sleep(1) returnthreads = []for i in range(5): t = threading.Thread(target=decorated_with_class) threads.append(t) t.start() |
希望本文所述对大家Python程序设计有所帮助。
