爬虫实战（黑马论坛）

1.定位爬取位置内容：

python 复制代码

# -*- coding: utf-8 -*-
import requests
import time
import re

# 请求的 URL 和头信息
url = 'https://bbs.itheima.com/forum-425-1.html'
headers = {
    'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36',
}

# 发起请求并等待 5 秒
response = requests.get(url, headers=headers)
time.sleep(5)

print(response.text)
# 使用正则表达式提取文章标题，发布时间，文章作者
# 文章标题：（关于Django项目《美多商城》的全部流程(下)--从购物车到部署）</a>]</em> <a href="http://bbs.itheima.com/thread-426625-1-1.html" onclick="atarget(this)" class="s xst">关于Django项目《美多商城》的全部流程(下)--从购物车到部署</a>
# 发布时间：（2018-10-28）<a href="http://bbs.itheima.com/home.php?mod=space&amp;uid=468765" c="1"><span style="margin-left: 0;">python_shenshou</span></a><span style="margin-left: 5px;">@ 2018-10-28</span><span style="margin-left: 18px;padding-left: 16px;background: url(/template/gfquan/src/replygf.jpg) no-repeat 0 0;">
# 文章作者: (python_shenshou)<a href="http://bbs.itheima.com/home.php?mod=space&amp;uid=468765" c="1"><span style="margin-left: 0;">python_shenshou</span></a><span style="margin-left: 5px;">@ 2018-10-28</span>

2.正则匹配提取出需要的内容：

python 复制代码

import requests
import re

# 请求的 URL 和头信息
url = 'https://bbs.itheima.com/forum-425-1.html'
headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36',
}

# 发起请求
response = requests.get(url, headers=headers)

if response.status_code == 200:
    # 使用正则表达式提取文章标题
    titles = re.findall(r'class="s xst">([^<]+)</a>', response.text)
    # 提取发布时间和作者
    details = re.findall(r'<span style="margin-left: 0;">([^<]+)</span></a><span style="margin-left: 5px;">@ ([^<]+)</span>', response.text)
    authors = [detail[0] for detail in details]
    dates = [detail[1] for detail in details]

    # 输出提取的结果
    for title, date, author in zip(titles, dates, authors):
        print(f"文章标题: {title}")
        print(f"发布时间: {date}")
        print(f"文章作者: {author}")
        print('-' * 40)
else:
    print("访问失败", response.status_code)

3.定位翻页进行多页爬取：

python 复制代码

import requests
import re


def fetch_page(url):
    headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36',
    }

    response = requests.get(url, headers=headers)
    if response.status_code == 200:
        # 使用正则表达式提取文章标题
        titles = re.findall(r'class="s xst">([^<]+)</a>', response.text)
        # 提取发布时间和作者
        details = re.findall(
            r'<span style="margin-left: 0;">([^<]+)</span></a><span style="margin-left: 5px;">@ ([^<]+)</span>',
            response.text)
        authors = [detail[0] for detail in details]
        dates = [detail[1] for detail in details]

        # 输出提取的结果
        for title, date, author in zip(titles, dates, authors):
            print(f"文章标题: {title}")
            print(f"发布时间: {date}")
            print(f"文章作者: {author}")
            print('-' * 40)

        # 使用正则表达式提取下一页的链接
        next_page_link = re.search(r'下一页', response.text)
        if next_page_link:
            return next_page_link.group(1)  # 返回完整的链接
        else:
            return None
    else:
        print("访问失败", response.status_code)
        return None


# 初始页面
current_url = 'https://bbs.itheima.com/forum-425-1.html'

# 循环遍历每一页，直到没有下一页
while current_url:
    print(f"正在爬取: {current_url}")
    next_url = fetch_page(current_url)
    current_url = next_url

4.最后爬取结果：

需要注意的地方：其中运用到的正则方法为([^<]+)，另一种的正则方法为(.*?)，建议第一种，效率更高，但是处理不了'<'字符情况，根据实际情况操作。