Python的多线程与多进程编程示例

Love The Way You Lie 2023-02-26 13:28 116阅读 0赞

### 使用示例： ###

#### 多进程： ####

# -*- coding: utf-8 -*-
    """
    Python多进程的简单使用
    """
    from multiprocessing import Process
    from os import getpid
    from random import randint
    from time import time, sleep
    
    
    def download_task(filename):
        print('启动下载进程，进程号[%d].' % getpid())
        print('开始下载%s...' % filename)
        time_to_download = randint(5, 10)
        sleep(time_to_download)
        print('%s下载完成! 耗费了%d秒' % (filename, time_to_download))
    
    
    def main():
        start = time()
        p1 = Process(target=download_task, args=('Python从入门到住院.pdf', ))
        p1.start()
        p2 = Process(target=download_task, args=('Peking Hot.avi', ))
        p2.start()
        p1.join()  # 等待进程1执行完毕，再执行下一步
        p2.join()  # 等待进程2执行完毕，再执行下一步
        end = time()
        print('总共耗费了%.2f秒.' % (end - start))
    
    
    if __name__ == '__main__':
        main()

#### 多线程： ####

# -*- coding: utf-8 -*-
    """
    Python的多线程简单使用
    """
    from random import randint
    from threading import Thread
    from time import time, sleep
    
    
    def download(filename):
        print('开始下载%s...' % filename)
        time_to_download = randint(5, 10)
        sleep(time_to_download)
        print('%s下载完成! 耗费了%d秒' % (filename, time_to_download))
    
    
    def main():
        start = time()
        t1 = Thread(target=download, args=('Python从入门到住院.pdf',))
        t1.start()
        t2 = Thread(target=download, args=('Peking Hot.avi',))
        t2.start()
        t1.join()  # 等待线程1执行完毕，再执行下一步
        t2.join()  # 等待线程2执行完毕，再执行下一步
        end = time()
        print('总共耗费了%.3f秒' % (end - start))
    
    
    if __name__ == '__main__':
        main()

或者通过继承Thread类的方式来创建自定义的线程类，然后再创建线程对象并启动线程：

from random import randint
    from threading import Thread
    from time import time, sleep
    
    
    class DownloadTask(Thread):
    
        def __init__(self, filename):
            super().__init__()
            self._filename = filename
    
        def run(self):
            print('开始下载%s...' % self._filename)
            time_to_download = randint(5, 10)
            sleep(time_to_download)
            print('%s下载完成! 耗费了%d秒' % (self._filename, time_to_download))
    
    
    def main():
        start = time()
        t1 = DownloadTask('Python从入门到住院.pdf')
        t1.start()
        t2 = DownloadTask('Peking Hot.avi')
        t2.start()
        t1.join()  # 等待线程1执行完毕，再执行下一步
        t2.join()  # 等待线程2执行完毕，再执行下一步
        end = time()
        print('总共耗费了%.2f秒.' % (end - start))
    
    
    if __name__ == '__main__':
        main()

**注意：**  
`在平时的使用中，就不需要调用join()来等待进程和线程的执行完毕了，不然会导致主进程和主线程的阻塞。`