python线程间通信

#!/usr/bin/python
# -*- coding:utf8 -*-

from threading import Thread, Lock
import random


def test_thread():
    # 线程间的通信
    # 使用锁来控制共享资源的访问
    a = 0
    n = 10000000
    lock = Lock()

    def imcr(n):
        global a
        for i in range(n):
            lock.acquire()  # 可以写成with lock:
            a += 1  # a+=1
            lock.release()

    def decr(n):
        for i in range(n):
            global a
            lock.acquire()
            a -= 1
            lock.release()

    t = Thread(target=imcr, args=(n,))
    t2 = Thread(target=decr, args=(n,))
    t.start()

    t2.start()
    t.join()
    t2.join()
    print(a)


# 多线程的消费者与生产者模式
# from threading import Thread
from queue import Queue

q = Queue(3)


class Producter(Thread):
    def __init__(self, queue):
        super().__init__()
        self.queue = queue

    def run(self):
        while True:
            item = random.randint(0, 99)
            self.queue.put(item)
            print('已产生%s' % item)


class Consumer(Thread):
    def __init__(self, queue):
        super().__init__()
        self.queue = queue

    def run(self):
        while True:
            item = self.queue.get()
            print(item)
            self.queue.task_done()  # 告诉队列这个任务执行完成


product = Producter(q)
consumer = Consumer(q)
product.start()
consumer.start()

# 注意，mgr=Manger() q.mgr.Queue()
# 进程版本的需要加一个input()或者是
# producter.join consumer.join()  因为一旦主进程结束，代码就不会继续运行了