45 lines
1.2 KiB
Python
45 lines
1.2 KiB
Python
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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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