• 生产者与消费者+Queue(线程安全)


    from queue import Queue
    from lxml import etree
    import requests
    from urllib import request
    from threading import Thread
    import re, os
    
    class Producter(Thread):
    
        def __init__(self, page_queue, img_queue, *args, **kwargs):
            super(Producter,self).__init__(*args, **kwargs)
            self.page_queue = page_queue
            self.img_queue = img_queue
            self.head = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36'
    
        def run(self):
            while True:
                url = self.page_queue.get()
                self.parse(url)
        def parse(self, url):
            res = requests.get(url, params=self.head)
            text = res.text
            html = etree.HTML(text)
            imgs = html.xpath('//div[@class="col-xs-6 col-sm-3"]//img[@class!="gif"]')
            print(imgs)
            for img in imgs:
                img_path = img.get('data-original')
                alt = img.get('alt')
                alt = re.sub(r'[??.。!!*]', '', alt)  # 将特殊符号替换
                sub = os.path.splitext(img_path)  # 获取文件后缀
                sub = re.sub(r'[(!dta)]', '', sub[1])
                filename = './imgs/'+alt+sub
                print(img_path, filename)
                self.img_queue.put((img_path, filename))
    
    
    class Consumer(Thread):
    
        def __init__(self, page_queue, img_queue, *args, **kwargs):
            super(Consumer, self).__init__(*args, **kwargs)
            self.page_queue = page_queue
            self.img_queue = img_queue
    
        def run(self):
            while True:
                url = self.img_queue.get()
                self.parse(url[0], url[1])
                print('消费者')
        def parse(self, url, path):
            # 下载文件到指定位置
            request.urlretrieve(url, path)
    
    
    def main():
        page_queue = Queue(10)
        img_queue = Queue(10000)
        for i in range(1, 11):
            uri = 'https://www.doutula.com/article/list/?page='+str(i)
            page_queue.put(uri)
        for i in range(5):
            t1 = Producter(page_queue, img_queue)
            t1.start()
        for i in range(5):
            t2 = Consumer(page_queue, img_queue)
            t2.start()
    
    
    if __name__ == '__main__':
        main()

    注意:

      如果使用threading.Lock(),或者threading.Condition(),都是线程不安全的,它们都是锁,共同方法(lock.acquire(),lock.release()),只不过Condition()有多了几个方法,wait()、notify()、notify_all(),如果等待的情况下,使用wait()将不占用CPU,当用资源消耗时,notify唤醒等待的线程。Lock()一直占用CPU资源。感觉还是Queue好用是吧。

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  • 原文地址:https://www.cnblogs.com/wbdream/p/10307312.html
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