mysql 去重con_python 爬虫 实现增量去重和定时爬取实例
前言： 在爬蟲(chóng)過(guò)程中，我們可能需要重復(fù)的爬取同一個(gè)網(wǎng)站，為了避免重復(fù)的數(shù)據(jù)存入我們的數(shù)據(jù)庫(kù)中 通過(guò)實(shí)現(xiàn)增量去重 去解決這一問(wèn)題 本文還針對(duì)了那些需要實(shí)時(shí)更新的網(wǎng)站 增加了一個(gè)定時(shí)爬取的功能；
本文作者同開(kāi)源中國(guó)(殊途同歸_)；
解決思路：
1.獲取目標(biāo)url
2.解析網(wǎng)頁(yè)
3.存入數(shù)據(jù)庫(kù)(增量去重)
4.異常處理
5.實(shí)時(shí)更新(定時(shí)爬取)
下面為數(shù)據(jù)庫(kù)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
接下來(lái)是主要代碼 test.py：
# 使用bs4進(jìn)行網(wǎng)頁(yè)解析
# 實(shí)現(xiàn)了增量去重
# 實(shí)現(xiàn)了定時(shí)爬取
import datetime
import time
from bs4 import BeautifulSoup
import requests
from mysql_config import insert_db
from 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('期號(hào)：%s\t時(shí)間：%s\t號(hào)碼:%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 已經(jīng)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
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