【Python实战案例】爬虫项目实例（附赠源码）

文章目录

- 声明
- 安装必要的库
- 项目结构
- 技术细节
- 小结

声明

在这里插入图片描述

请您遵守网站的robots文件规定，本文目的只是做学习交流使用，包括多个模块，例如数据存储、日志记录、错误处理、多线程或异步请求

安装必要的库

pip install requests beautifulsoup4 sqlite3

项目结构

创建以下文件和目录结构
my_crawler/
├── config.py
├── crawler.py
├── db.py
├── logger.py
└── main.py

技术细节

配置文件 config.py
配置文件用于存储常量和配置项：

BASE_URL = 'https://example.com'
ARTICLES_URL = f'{BASE_URL}/articles'
DATABASE_NAME = 'articles.db'
LOG_FILE = 'crawler.log'

1.数据库操作 db.py
用于创建数据库表和插入数据：

#db.pyimport sqlite3
from config import DATABASE_NAMEdef init_db():conn = sqlite3.connect(DATABASE_NAME)cursor = conn.cursor()cursor.execute('''CREATE TABLE IF NOT EXISTS articles (id INTEGER PRIMARY KEY AUTOINCREMENT,title TEXT NOT NULL,url TEXT NOT NULL)''')conn.commit()conn.close()def insert_article(title, url):conn = sqlite3.connect(DATABASE_NAME)cursor = conn.cursor()cursor.execute('INSERT INTO articles (title, url) VALUES (?, ?)', (title, url))conn.commit()conn.close()

2.日志记录 logger.py
用于配置日志记录：

logger.pyimport logging
from config import LOG_FILEdef setup_logger():logging.basicConfig(filename=LOG_FILE,level=logging.INFO,format='%(asctime)s - %(levelname)s - %(message)s')logger = setup_logger()

3.爬虫逻辑 crawler.py
包含爬虫的主要逻辑：

 crawler.pyimport requests
from bs4 import BeautifulSoup
from config import ARTICLES_URL
from db import insert_article
from logger import loggerdef fetch_page(url):"""获取网页内容"""try:response = requests.get(url)response.raise_for_status()  # 检查请求是否成功return response.textexcept requests.RequestException as e:logger.error(f"请求错误: {e}")return Nonedef parse_html(html):"""解析HTML，提取文章标题和URL"""soup = BeautifulSoup(html, 'html.parser')articles = []for article in soup.find_all('div', class_='article'):title = article.find('h1', class_='article-title').get_text(strip=True)url = article.find('a')['href']articles.append((title, url))return articlesdef crawl_articles():"""抓取并保存文章"""html = fetch_page(ARTICLES_URL)if html:articles = parse_html(html)for title, url in articles:insert_article(title, url)logger.info(f"已保存文章: {title} - {url}")

主程序 main.py
启动爬虫的主程序：

 main.pyfrom crawler import crawl_articles
from db import init_db
from logger import loggerdef main():logger.info("开始爬虫任务")init_db()crawl_articles()logger.info("爬虫任务完成")if __name__ == '__main__':main()