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这篇文章主要讲解了Python使用队列方式实现多线程爬虫的方法，内容清晰明了，对此有兴趣的小伙伴可以学习一下，相信大家阅读完之后会有帮助。
说明：糗事百科段子的爬取，采用了队列和多线程的方式，其中关键点是Queue.task_done()、Queue.join()，保证了线程的有序进行。
代码如下
import requests
from lxml import etree
import json
from queue import Queue
import threading
class Qsbk(object):
def __init__(self):
self.headers = {
"User-Agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36",
"Referer": "https://www.qiushibaike.com/"
}
# 实例化三个队列，用来存放内容
self.url_queue = Queue()
self.html_queue = Queue()
self.content_queue = Queue()
def get_total_url(self):
"""
获取了所有的页面url，并且返回url_list
return:url_list
现在放入url_queue队列中保存
"""
url_temp = "https://www.qiushibaike.com/text/page/{}/"
url_list = list()
for i in range(1,13):
# url_list.append(url_temp.format(i))
# 将生成的url放入url_queue队列
self.url_queue.put(url_temp.format(i))
def parse_url(self):
"""
发送请求，获取响应，同时etree处理html
"""
while self.url_queue.not_empty:
# 判断非空，为空时结束循环
# 从队列中取出一个url
url = self.url_queue.get()
print("parsing url:",url)
# 发送请求
response = requests.get(url,headers=self.headers,timeout=10)
# 获取html字符串
html = response.content.decode()
# 获取element类型的html
html = etree.HTML(html)
# 将生成的element对象放入html_queue队列
self.html_queue.put(html)
# Queue.task_done() 在完成一项工作之后，Queue.task_done()函数向任务已经完成的队列发送一个信号
self.url_queue.task_done()
def get_content(self):
"""
解析网页内容，获取想要的信息
"""
while self.html_queue.not_empty:
items = list()
html = self.html_queue.get()
total_div = html.xpath("//div[@class='col1 old-style-col1']/div")
for i in total_div:
author_img = i.xpath(".//a[@rel='nofollow']/img/@src")
author_img = "https"+author_img[0] if len(author_img)>0 else None
author_name = i.xpath(".//a[@rel='nofollow']/img/@alt")
author_name = author_name[0] if len(author_name)>0 else None
author_href = i.xpath("./a/@href")
author_href = "https://www.qiushibaike.com/"+author_href[0] if len(author_href)>0 else None
author_gender = i.xpath("./div[1]/div/@class")
author_gender = author_gender[0].split(" ")[-1].replace("Icon","").strip() if len(author_gender)>0 else None
author_age = i.xpath("./div[1]/div/text()")
author_age = author_age[0] if len(author_age)>0 else None
content = i.xpath("./a/div/span/text()")
content = content[0].strip() if len(content)>0 else None
content_vote = i.xpath("./div[@class='stats']/span[@class='stats-vote']/i/text()")
content_vote = content_vote[0] if len(content_vote)>0 else None
content_comment_numbers = i.xpath("./div[@class='stats']/span[@class='stats-comments']/a/i/text()")
content_comment_numbers = content_comment_numbers[0] if len(content_comment_numbers)>0 else None
item = {
"author_name":author_name,
"author_age" :author_age,
"author_gender":author_gender,
"author_img":author_img,
"author_href":author_href,
"content":content,
"content_vote":content_vote,
"content_comment_numbers":content_comment_numbers,
}
items.append(item)
self.content_queue.put(items)
# task_done的时候，队列计数减一
self.html_queue.task_done()
def save_items(self):
"""
保存items
"""
while self.content_queue.not_empty:
items = self.content_queue.get()
with open("quishibaike.txt",'a',encoding='utf-8') as f:
for i in items:
json.dump(i,f,ensure_ascii=False,indent=2)
self.content_queue.task_done()
def run(self):
# 获取url list
thread_list = list()
thread_url = threading.Thread(target=self.get_total_url)
thread_list.append(thread_url)
# 发送网络请求
for i in range(10):
thread_parse = threading.Thread(target=self.parse_url)
thread_list.append(thread_parse)
# 提取数据
thread_get_content = threading.Thread(target=self.get_content)
thread_list.append(thread_get_content)
# 保存
thread_save = threading.Thread(target=self.save_items)
thread_list.append(thread_save)
for t in thread_list:
# 为每个进程设置为后台进程，效果是主进程退出子进程也会退出
t.setDaemon(True)
t.start()
# 让主线程等待，所有的队列为空的时候才能退出
self.url_queue.join()
self.html_queue.join()
self.content_queue.join()
if __name__=="__main__":
obj = Qsbk()
obj.run()