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()

更多关于Python相关内容可查看本站专题：《Python数据结构与算法教程》、《Python Socket编程技巧总结》、《Python函数使用技巧总结》、《Python字符串操作技巧汇总》及《Python入门与进阶经典教程》

希望本文所述对大家Python程序设计有所帮助。

声明：本文内容来源于网络，版权归原作者所有，内容由互联网用户自发贡献自行上传，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任。如果您发现有涉嫌版权的内容，欢迎发送邮件至：notice#nhooo.com（发邮件时，请将#更换为@）进行举报，并提供相关证据，一经查实，本站将立刻删除涉嫌侵权内容。