python之进程和线程

python实现进程和线程

1、多进程实现代码：

​

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()
    p2.join()
    end = time()
    print('总共耗费了%.2f秒.' % (end - start))


if __name__ == '__main__':
    main()

2、多线程实现代码：

​ （1）通过创建Thread类进行创建：

​

from threading import Thread
from random import randint
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()
    thread1=Thread(target=download, args=('Python从入门到住院.pdf',))
    thread2=Thread(target=download,args=('Peking Hot.avi',))
    thread1.start()
    thread2.start()
    thread1.join()
    thread2.join()
    end=time()
    print('总共消耗了%.3f秒'%(end-start))

if __name__=='__main__':
    main()

(2)通过继承Thread类：

​

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()
    t2.join()
    end = time()
    print('总共耗费了%.2f秒.' % (end - start))


if __name__ == '__main__':
    main()