python-线程池的两种实现方式 【转载】

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 
 import queue
 import threading
 import contextlib
 import time
 
 StopEvent = object()
 
 class ThreadPool(object):
 
     def __init__(self, max_num, max_task_num = None):
         if max_task_num:
             self.q = queue.Queue(max_task_num)
         else:
             self.q = queue.Queue()
         self.max_num = max_num
         self.cancel = False
         self.terminal = False
         self.generate_list = []
         self.free_list = []
 
     def run(self, func, args, callback=None):
         """
         线程池执行一个任务
         :param func: 任务函数
         :param args: 任务函数所需参数
         :param callback: 任务执行失败或成功后执行的回调函数，回调函数有两个参数1、任务函数执行状态；2、任务函数返回值（默认为None，即：不执行回调函数）
         :return: 如果线程池已经终止，则返回True否则None
         """
         if self.cancel:
             return
         if len(self.free_list) == 0 and len(self.generate_list) < self.max_num:
             self.generate_thread()
         w = (func, args, callback,)
         self.q.put(w)
 
     def generate_thread(self):
         """
         创建一个线程
         """
         t = threading.Thread(target=self.call)
         t.start()
 
     def call(self):
         """
         循环去获取任务函数并执行任务函数
         """
         current_thread = threading.currentThread()
         self.generate_list.append(current_thread)
 
         event = self.q.get()
         while event != StopEvent:
 
             func, arguments, callback = event
             try:
                 result = func(*arguments)
                 success = True
             except Exception as e:
                 success = False
                 result = None
 
             if callback is not None:
                 try:
                     callback(success, result)
                 except Exception as e:
                     pass
 
             with self.worker_state(self.free_list, current_thread):
                 if self.terminal:
                     event = StopEvent
                 else:
                     event = self.q.get()
         else:
 
             self.generate_list.remove(current_thread)
 
     def close(self):
         """
         执行完所有的任务后，所有线程停止
         """
         self.cancel = True
         full_size = len(self.generate_list)
         while full_size:
             self.q.put(StopEvent)
             full_size -= 1
 
     def terminate(self):
         """
         无论是否还有任务，终止线程
         """
         self.terminal = True
 
         while self.generate_list:
             self.q.put(StopEvent)
 
         self.q.queue.clear()
 
     @contextlib.contextmanager
     def worker_state(self, state_list, worker_thread):
         """
         用于记录线程中正在等待的线程数
         """
         state_list.append(worker_thread)
         try:
             yield
         finally:
             state_list.remove(worker_thread)
 
 # How to use
 
 pool = ThreadPool(5)
 
 def callback(status, result):
     # status, execute action status
     # result, execute action return value
     pass
 
 def action(i):
     print(i)
 
 for i in range(30):
     ret = pool.run(action, (i,), callback)
 
 time.sleep(5)
 print(len(pool.generate_list), len(pool.free_list))
 print(len(pool.generate_list), len(pool.free_list))
 # pool.close()
 # pool.terminate()

线程池（优秀）

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 import Queue
 import threading
 
 class ThreadPool(object):
 
     def __init__(self, max_num=20):
         self.queue = Queue.Queue(max_num)
         for i in xrange(max_num):
             self.queue.put(threading.Thread)
 
     def get_thread(self):
         return self.queue.get()
 
     def add_thread(self):
         self.queue.put(threading.Thread)
 
 """
 pool = ThreadPool(10)
 
 def func(arg, p):
     print arg
     import time
     time.sleep(2)
     p.add_thread()
 
 for i in xrange(30):
     thread = pool.get_thread()
     t = thread(target=func, args=(i, pool))
     t.start()
 """

转载
作者：武沛齐 
出处：http://www.cnblogs.com/wupeiqi/