前言： 在爬虫过程中，我们可能需要重复的爬取同一个网站，为了避免重复的数据存入我们的数据库中 通过实现增量去重 去解决这一问题 本文还针对了那些需要实时更新的网站 增加了一个定时爬取的功能；

本文作者同开源中国（殊途同归_）；

解决思路：

1.获取目标url

2.解析网页

3.存入数据库（增量去重）

4.异常处理

5.实时更新（定时爬取）

下面为数据库的配置 mysql_congif.py：

import pymysql def insert_db(db_table, issue, time_str, num_code): host = '127.0.0.1' user = 'root' password = 'root' port = 3306 db = 'lottery' data_base = pymysql.connect(host=host, user=user, password=password, port=port, db=db) cursor = data_base.cursor() try: sql = "INSERT INTO %s VALUES ('%s','%s','%s')" % (db_table, issue, time_str, num_code) cursor.execute(sql) data_base.commit() except ValueError as e: print(e) data_base.rollback() finally: cursor.close() data_base.close() def select_db(issue, db_table): host = '127.0.0.1' user = 'root' password = 'root' port = 3306 db = 'lottery' data_base = pymysql.connect(host=host, user=user, password=password, port=port, db=db) cursor = data_base.cursor() try: sql = "SELECT '%s' FROM %s " % (issue, db_table) cursor.execute(sql) data_base.commit() except ValueError as e: print(e) data_base.rollback() finally: return issue

接下来是主要代码 test.py：

# 使用bs4进行网页解析# 实现了增量去重# 实现了定时爬取import datetimeimport time from bs4 import BeautifulSoupimport requests from mysql_config import insert_dbfrom mysql_config import select_db def my_test(): db_table = 'lottery_table' url = 'http://kj.13322.com/kl10_dkl10_history_dtoday.html' res = requests.get(url) content = res.content soup = BeautifulSoup(content, 'html.parser', from_encoding='utf8') c_t = soup.select('#trend_table')[0] trs = c_t.contents[4:] for tr in trs: if tr == '\n': continue tds = tr.select('td') issue = tds[1].text time_str = tds[0].text num_code = tr.table.text.replace('\n0', ',').replace('\n', ',').strip(',') print('期号：%s\t时间：%s\t号码:%s' % (str(issue), str(time_str), str(num_code))) issue_db = select_db(issue, db_table) try: if issue_db == issue: insert_db(db_table, issue_db, time_str, num_code) print('添加%s到%s成功' % (issue_db, db_table)) except Exception as e: print('%s 已经存在！' % issue_db) print(e) if __name__ == '__main__': flag = 0 now = datetime.datetime.now() sched_time = datetime.datetime(now.year, now.month, now.day, now.hour, now.minute, now.second) +\ datetime.timedelta(seconds=3) while True: now = datetime.datetime.now() if sched_time < now: time.sleep(3) print(now) my_test() flag = 1 else: if flag == 1: sched_time = sched_time + datetime.timedelta(minutes=2) flag = 0

以上这篇python 爬虫 实现增量去重和定时爬取实例就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。