内容概要：
1.low版线程池
2.绝版线程池
1.low版线程池
设计思路：运用队列queue
将线程类名放入队列中，执行一个就拿一个出来
import queue
import threading class ThreadPool(object): def __init__(self, max_num=20):
self.queue = queue.Queue(max_num) #创建队列，最大数为20
for i in range(max_num):
self.queue.put(threading.Thread) #将类名放入队列中 def get_thread(self):
return self.queue.get() #从队列中取出类名 def add_thread(self):
self.queue.put(threading.Thread) #进类名放入队列中 def func(arg, p): #定义一个函数
print(arg)
import time
time.sleep(2)
p.add_thread() pool = ThreadPool(10) #创建对象，并执行该类的构造方法，即将线程的类名放入队列中 for i in range(30):
thread = pool.get_thread() #调用该对象的get_thread方法，取出类名
t = thread(target=func, args=(i, pool)) #创建对象，执行func，参数在args中
t.start()
由于此方法要求使用者修改原函数，并在原函数里传参数，且调用方法也发生了改变，并且有空闲线程浪费资源，实际操作中并不方便，故设计了下一版线程池。
2.绝版线程池
设计思路：运用队列queue
a.队列里面放任务
b.线程一次次去取任务，线程一空闲就去取任务
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, args, callback = event
try:
result = func(*args)
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
count = len(self.generate_list)
while count:
self.q.put(StopEvent)
count -= 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(3)
print(len(pool.generate_list), len(pool.free_list))
print(len(pool.generate_list), len(pool.free_list))
pool.close()
# pool.terminate()