python爬虫使用笔记

import requests url请求
import threading 多线程
from bs4 import BeautifulSoup 网页抓取元素扩展，类似JQ
import datetime 时间库
import hashlib hash库，用来计算文件hash，防止重复下载文件
import os,sys,os.path 系统IO处理库
import random 随机数库
import re 正则库
import urllib.request URL请求库

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import pymysql
import time

class MySQL:

error_code = '' #MySQL错误号码

_instance = None #本类的实例
_conn = None # 数据库conn
_cur = None #游标

_TIMEOUT = 30 #默认超时30秒
_timecount = 0

def __init__(self, dbconfig):
self._conn = pymysql.connect(host=dbconfig['host'],
port=dbconfig['port'],
user=dbconfig['user'],
passwd=dbconfig['passwd'],
db=dbconfig['db'],
charset=dbconfig['charset'])

self._cur = self._conn.cursor()
self._instance = pymysql

def query(self,sql,str=''):
self._cur.execute("SET NAMES utf8")
if (str != ''):
return self._cur.execute(sql,str)
else:
return self._cur.execute(sql)

def update(self,sql,str=''):
try:
self._cur.execute("SET NAMES utf8")
if (str != ''):
return self._cur.execute(sql,str)
else:
return self._cur.execute(sql)
self._conn.commit()
except Exception :print("发生异常")
return result

def insert(self,sql,str=''):
self._cur.execute("SET NAMES utf8")
if (str != ''):
return self._cur.execute(sql,str)
else:
return self._cur.execute(sql)
self._conn.commit()
return self._cur.lastrowid

def fetchAllRows(self):
return self._cur.fetchall()

def fetchOneRow(self):
return self._cur.fetchone()

def getRowCount(self):
return self._cur.rowcount

def commit(self):
self._conn.commit()

def rollback(self):
self._conn.rollback()

def __del__(self):
try:
self._cur.close()
self._conn.close()
except:
pass

def close(self):
self.__del__()

# if __name__ == '__main__':
# # 数据库连接参数
# dbconfig = {'host':'',
# 'port': ,
# 'user':'',
# 'passwd':'',
# 'db':'',
# 'charset':'utf8'}
#
# # # 连接数据库，创建这个类的实例
# # db = MySQL(dbconfig)
# #
# # # 操作数据库
# # sql = "insert into cmf_gifs(name) values('123')"
# # # sql2 = "UPDATE lbs_member SET username='123' WHERE userid=123"
# # # sql3 = "SELECT * FROM lbs_member LIMIT 5"
# # # db.query(sql)
# # # result = db.fetchAllRows()
# # # result = db.update(sql2)
# # result = db.insert(sql)
# # print(result)
# # db.close()