深入浅出分析Python装饰器用法

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：

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
@ita
def sayhi():
 return 'hi'

改进一：

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：

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：

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 word
print(say())
print(say('Hello'))

示例二

最初代码：

import threading
import time
class 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)
 return
threads = []
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

import threading
import time
class 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)
 return
threads = []
for i in range(5):
 t = threading.Thread(target=decorated_with_class)
 threads.append(t)
 t.start()