生产者与消费者+Queue（线程安全）

佚名 5年前 (2019-01-23) Python 1653人围观抢沙发百度已收录

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。

SRE实战互联网时代守护先锋，助力企业售后服务体系运筹帷幄！一键直达领取阿里云限量特价优惠。