第10课-队列、使用多线程和队列的爬虫案例

1、队列代码示例

import threading
import time
from queue import Queue
'''
Queue是线程安全的队列
'''
def set_data(q):
    index = 0
    while True:
        q.put(index)
        index += 1
        time.sleep(3)

def get_data(q):
    while True:
        print(q.get())

if __name__ == '__main__':
    q = Queue(4)
    t1 = threading.Thread(target=set_data,args=[q])
    t2 = threading.Thread(target=get_data,args=[q])
    t1.start()
    t2.start()
    q = Queue(1)
    q.put(1)
    q.get(timeout=1)
    print(q.empty())
    print(q.full(timeout=1))
    print(q.qsize())

2、斗图爬虫实战

import requests
import threading
from queue import Queue
from lxml import etree
from urllib import  request

g_flag = True
HEADERS = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36"
}

#爬取图片地址
def put_picture_link(q):
    global g_flag
    for i in range(1,11):
        text = requests.get(url="http://www.doutula.com/article/list/?page={}".format(i), headers=HEADERS).text
        html = etree.HTML(text)
        imgs_elements = html.xpath(
            '//div[@class="col-sm-9 center-wrap"]/a/div[@class="random_article"]/div/img [@class!="gif"]')
        for img_element in imgs_elements:
            image_link = img_element.xpath("@data-original")[0]
            q.put(image_link)
    g_flag = False


#下载图片
def download(q):
    index = 1
    while g_flag or q.qsize()>0:
        img_link = q.get(timeout=1)
        result = requests.get(url=img_link)
        if result.status_code == 200:
            my_picture = result.content
            append = img_link.split(".")[-1]
            with open("c://pictures/{}.{}".format(index, append), "wb") as fp:
                fp.write(my_picture)
            #文件下载
            # request.urlretrieve(url=img_link,filename="c://pictures/{}.{}".format(index, append))
            index += 1


if __name__ == '__main__':
    q = Queue(10)  #初始化队列
    t1 = threading.Thread(target=put_picture_link,args=[q])
    t1.start()
    t2 = threading.Thread(target=download,args=[q])
    t2.start()
    print("主线程执行完毕!!!")

3、百思不得姐爬虫实战

"""百思不得姐爬虫实战"""
import threading
from lxml import etree
import requests
from queue import Queue
import csv

g_Lock = threading.Lock()
g_flag = True

DOMAIN = "http://www.budejie.com/"
HEADERS = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36"
}
#生产者
class Producer(threading.Thread):
    def __init__(self,queue_url,queue_content):
        super(Producer,self).__init__()
        self.__queue_url = queue_url
        self.__queue_content = queue_content
    def run(self):
        global g_flag
        # count = 1

        while self.__queue_url.qsize()>0:
            url = self.__queue_url.get()
            text = requests.get(url= url,headers = HEADERS).text
            html = etree.HTML(text)
            contents = html.xpath('//div[@class="g-mn"]//div[@class="j-r-list"]//ul//div[@class="j-r-list-c-desc"]/a')

            for c in contents:
                content = c.xpath("text()")[0].replace(r"u200b","")
                link = DOMAIN + c.xpath("@href")[0]
                content_dict = {}
                content_dict["段子"] = content
                content_dict["链接"] = link
                self.__queue_content.put(content_dict)
            # print("第{}个页面请求成功".format(count))
            # count += 1

        g_flag = False

        print("-----------------------所有请求已完成---------------")

#消费者
class Consumer(threading.Thread):
    def __init__(self,queue_content,writer,i):
        super(Consumer,self).__init__()
        self.__queue_content = queue_content
        self.__writer = writer
        self.__i = i

    def run(self):
        print("----dddddddddddddd---")
        while True:
            if self.__queue_content.qsize()>0 or g_flag :
                try:
                    content_dict = self.__queue_content.get(timeout=1)
                    g_Lock.acquire()
                    self.__writer.writerow(content_dict)
                    g_Lock.release()
                except Exception as e:
                    print("队列为空{}".format(e))
            else:
                break
            print("线程{}".format(self.__i),g_flag, self.__queue_content.qsize())



if __name__ == '__main__':
    q_url = Queue(100)
    q_content = Queue(100)
    for i in range(1,25):
        q_url.put("http://www.budejie.com/text/{}".format(i))

    header = ["段子","链接"]
    fp = open("text.csv","w",encoding="utf-8",newline="")
    writer = csv.DictWriter(fp,header)
    writer.writeheader()
    for i in range(0,1):
        c = Consumer(q_content,writer,i)
        c.start()
    p = Producer(q_url,q_content)
    p.start()