Python分别用单线程，多线程，异步协程爬取一部小说，最快仅需要5s

本文运用了三种方式爬取一整部小说，分别运用了单线程爬取，多线程爬取和异步协程爬取。
小说网址：`

http://www.doupo321.com/doupocangqiong/`

网页很简单，也不用过多分析，内容都在网页源代码中，就是一个多级链接爬虫，步骤就是先爬取到网页下的子链接，然后通过子链接爬取到每章小说内容。
因为这个网页的源代码都很规整，所有我们用xpath来匹配，当然你熟悉正则或者bs4也可以用bs4来匹配。然后我们就开始写代码吧。

单线程爬取

# @Time:2022/1/1312:04
# @Author:中意灬
# @File:斗破2.py
# @ps:tutu qqnum:2117472285
import time
import requests
from lxml import etree
def download(url,title):#下载内容
    resp=requests.get(url)
    resp.encoding='utf-8'
    html=resp.text
    tree=etree.HTML(html)
    body = tree.xpath("/html/body/div/div/div[4]/p/text()")
    body = '\n'.join(body)
    with open(f'斗破2/{title}.txt',mode='w',encoding='utf-8')as f:
        f.write(body)
def geturl(url):#获取子链接
    resp=requests.get(url)
    resp.encoding='utf-8'
    html=resp.text
    tree=etree.HTML(html)
    lis=tree.xpath("/html/body/div[1]/div[2]/div[1]/div[3]/div[2]/ul/li")
    for li in lis:
        href=li.xpath("./a/@href")[0].strip('//')
        href="http://"+href
        title=li.xpath("./a/text()")[0]
        download(href,title)
if __name__ == '__main__':
    url="http://www.doupo321.com/doupocangqiong/"
    t1=time.time()
    geturl(url)
    t2=time.time()
    print("耗时：",t2-t1)

运行结果：

多线程爬取

# @Time:2022/1/1311:42
# @Author:中意灬
# @File:斗破1.py
# @ps:tutu qqnum:2117472285
import time
import requests
from lxml import etree
from concurrent.futures import ThreadPoolExecutor
def download(url,title):
    resp=requests.get(url)
    resp.encoding='utf-8'
    html=resp.text
    tree=etree.HTML(html)
    body = tree.xpath("/html/body/div/div/div[4]/p/text()")
    body = '\n'.join(body)
    with open(f'斗破1/{title}.txt',mode='w',encoding='utf-8')as f:
        f.write(body)
def geturl(url):
    resp = requests.get(url)
    resp.encoding = 'utf-8'
    html = resp.text
    tree = etree.HTML(html)
    lis = tree.xpath("/html/body/div[1]/div[2]/div[1]/div[3]/div[2]/ul/li")
    return lis

if __name__ == '__main__':
    url="http://www.doupo321.com/doupocangqiong/"
    t1=time.time()
    lis=geturl(url)
    with ThreadPoolExecutor(1000)as t:#创建线程池，有1000个线程
        for li in lis:
            href = li.xpath("./a/@href")[0].strip('//')
            href = "http://" + href
            title = li.xpath("./a/text()")[0]
            t.submit(download,url=href,title=title)
    t2=time.time()
    print("耗时：",t2-t1)

运行结果：

异步协程爬取

# @Time:2022/1/1310:30
# @Author:中意灬
# @File:斗破.py
# @ps:tutu qqnum:2117472285
import requests
import aiohttp
import asyncio
import aiofiles
from lxml import etree
import time
async def download(url,title,session):
        async with session.get(url) as resp:#resp=requst.get()
            html= await resp.text()
            tree=etree.HTML(html)
            body=tree.xpath("/html/body/div/div/div[4]/p/text()")
            body='\n'.join(body)
        async with aiofiles.open(f'斗破/{title}.txt',mode='w',encoding='utf-8')as f:#保存下载内容
                await f.write(body)

async def geturl(url):
    resp=requests.get(url)
    resp.encoding='utf-8'
    html=resp.text
    tree=etree.HTML(html)
    lis=tree.xpath("/html/body/div[1]/div[2]/div[1]/div[3]/div[2]/ul/li")
    tasks=[]
    async with aiohttp.ClientSession() as session:#request
        for li in lis:
            href=li.xpath("./a/@href")[0].strip('//')
            href="http://"+href
            title=li.xpath("./a/text()")[0]
    # 插入异步操作
            tasks.append(asyncio.create_task(download(href,title,session)))
        await asyncio.wait(tasks)
if __name__ == '__main__':
    url="http://www.doupo321.com/doupocangqiong/"
    t1=time.time()
    loop = asyncio.get_event_loop()
    loop.run_until_complete(geturl(url))
    t2=time.time()
    print("耗时：",t2-t1)

运行结果：

因为没有进行排序，所以爬取出来的章节都是乱序的，大家可以写爬虫的时候里面自己设置一下标题，这样爬取出来的顺序就可能是有序的了。
我们可以看出，用多线程，仅仅5秒就扒完了一部1600多章的小说，但是多线程会对系统的开销较大；如果用异步协程，爬取速度会稍微慢些，需要大概20多秒，但是对系统开销较小，建议大家采用异步协程的方式，但是用单线程去爬取会慢很多，扒完一部小说耗时需要9分多钟，不是很推荐。