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GitHub Repository: jackfrued/Python-100-Days
 Path: blob/master/Day01-15/code/Day13/multithread1.py
Views: 729
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"""

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使用多线程的情况 - 模拟多个下载任务

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Version: 0.1

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Author: 骆昊

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Date: 2018-03-20

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"""

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from random import randint

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from time import time, sleep

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import atexit

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import _thread

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def download_task(filename):

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    print('开始下载%s...' % filename)

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    time_to_download = randint(5, 10)

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    print('剩余时间%d秒.' % time_to_download)

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    sleep(time_to_download)

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    print('%s下载完成!' % filename)

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def shutdown_hook(start):

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    end = time()

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    print('总共耗费了%.3f秒.' % (end - start))

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def main():

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    start = time()

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    # 将多个下载任务放到多个线程中执行

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    thread1 = _thread.start_new_thread(download_task, ('Python从入门到住院.pdf',))

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    thread2 = _thread.start_new_thread(download_task, ('Peking Hot.avi',))

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    # 注册关机钩子在程序执行结束前计算执行时间

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    atexit.register(shutdown_hook, start)

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if __name__ == '__main__':

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    main()

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# 执行这里的代码会引发致命错误(不要被这个词吓到) 因为主线程结束后下载线程再想执行就会出问题

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# 需要说明一下 由于_thread模块属于比较底层的线程操作而且不支持守护线程的概念

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# 在实际开发中会有诸多不便 因此我们推荐使用threading模块提供的高级操作进行多线程编程

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