吴裕雄 python 爬虫（3）

import hashlib

md5 = hashlib.md5()
md5.update(b'Test String')
print(md5.hexdigest())

import hashlib

md5 = hashlib.md5(b'Test String').hexdigest()
print(md5)

import os
import hashlib 
import requests

# url = "http://opendata.epa.gov.tw/ws/Data/REWXQA/?$orderby=SiteName&$skip=0&$top=1000&format=json"
url = "https://www.baidu.com"

# 读取网页原始码
html=requests.get(url).text.encode('utf-8-sig')
# 判断网页是否更新
md5 = hashlib.md5(html).hexdigest()
if os.path.exists('F:\pythonBase\pythonex\ch06\old_md5.txt'):
    with open('F:\pythonBase\pythonex\ch06\old_md5.txt', 'r') as f:
        old_md5 = f.read()
    with open('F:\pythonBase\pythonex\ch06\old_md5.txt', 'w') as f:
        f.write(md5)
else:
    with open('F:\pythonBase\pythonex\ch06\old_md5.txt', 'w') as f:
        f.write(md5)

if md5 != old_md5:
    print('数据已更新...') 
else:
    print('数据未更新，从数据库读取...')

import os
import ast
import hashlib
import sqlite3
import requests

from bs4 import BeautifulSoup

conn = sqlite3.connect('F:\pythonBase\pythonex\DataBasePM25.sqlite') # 建立数据库连接
cursor = conn.cursor() # 建立 cursor 对象

# 建立一个数据表
sqlstr='''
CREATE TABLE IF NOT EXISTS TablePM25 ("no" INTEGER PRIMARY KEY AUTOINCREMENT 
NOT NULL UNIQUE ,"SiteName" TEXT NOT NULL ,"PM25" INTEGER)
'''
cursor.execute(sqlstr)

url = "http://api.help.bj.cn/apis/aqilist/"
#html=requests.get(url).text.encode('utf-8-sig')  # 读取网页原始码
html=requests.get(url).text.encode('iso-8859-1').decode('utf-8-sig')
# print(html)
html = html.encode('utf-8-sig')
# 判断网页是否更新
md5 = hashlib.md5(html).hexdigest()
old_md5 = ""

if os.path.exists('F:\pythonBase\pythonex\ch06\old_md5-.txt'):
    with open('F:\pythonBase\pythonexch06\old_md5-.txt', 'r') as f:
        old_md5 = f.read()
with open('F:\pythonBase\pythonexch06\old_md5-.txt', 'w') as f:
        f.write(md5)
print("old_md5="+old_md5+";"+"md5="+md5)  #显示新老md5码进行观察
if md5 != old_md5:
    print('数据已更新...')    
    sp=BeautifulSoup(html,'html.parser')   #解析网页内容
    jsondata = ast.literal_eval(sp.text)  #此时jscondata取到的是字典类型数据
    # 删除数据表内容
    js1=jsondata.get("aqidata")     #取出字典数据中的aqidata项的值（值是列表）
    conn.execute("delete from TablePM25")
    conn.commit()
    n=1
    for city in js1:   #city此时是列表js1中的第一条字典数据
        CityName=city["city"]  #取出city字典数据中的值为"city"的key         
        if(city["pm2_5"] == ""):
            PM25=0
        else:   #如果city字典中的key对应的value为空，则PM25=0,否则，把PM25=value  
            PM25=int(city["pm2_5"])             
        print("城市:{}   PM2.5={}".format(CityName,PM25))   #显示城市对应的名称与PM2.5值
        # 新增一笔记录
        sqlstr="insert into TablePM25 values({},'{}',{})" .format(n,CityName,PM25)
        cursor.execute(sqlstr)
        n+=1
        conn.commit() # 主动更新 
else:
    print('数据未更新，从数据库读取...') 
    cursor=conn.execute("select *  from TablePM25")
    rows=cursor.fetchall()
    for row in rows:
        print("城市:{}   PM2.5={}".format(row[1],row[2]))    

conn.close()  # 关闭数据库连

........................................................

import os
import ast
import hashlib
import sqlite3
import requests

from bs4 import BeautifulSoup

# cur_path=os.path.dirname(__file__) # 取得目前路径
# print(cur_path)
conn = sqlite3.connect('F:\pythonBase\pythonex\' + 'DataBasePM25.sqlite') # 建立数据库连接
cursor = conn.cursor() # 建立 cursor 对象

# 建立一个数据表
sqlstr='''
CREATE TABLE IF NOT EXISTS TablePM25 ("no" INTEGER PRIMARY KEY AUTOINCREMENT 
NOT NULL UNIQUE ,"SiteName" TEXT NOT NULL ,"PM25" INTEGER)
'''
cursor.execute(sqlstr)

url = "http://api.help.bj.cn/apis/aqilist/"
# 读取网页原始码
# html=requests.get(url).text.encode('utf-8-sig')
html=requests.get(url).text.encode('iso-8859-1').decode('utf-8-sig')
# print(html)
html = html.encode('utf-8-sig')

print('数据已更新...')    
sp=BeautifulSoup(html,'html.parser')    #sp是bs4.Beautifulsoup类
# 将网页内转换为 list,list 中的元素是 dict 
jsondata = ast.literal_eval(sp.text)   #把sp.text字符串转为dict类型
js=jsondata.get("aqidata")  #从jasondata中取出值为"aqidata"的key对应的value的列表

# 删除数据表内容
conn.execute("delete from TablePM25")
conn.commit()

#把抓到的数据逐条存到数据库
n=1
for city in js:
    CityName=city["city"]
    PM25=0 if city["pm2_5"] == "" else int(city["pm2_5"])     
    print("城市:{}   PM2.5={}".format(CityName,PM25))
    # 新增一条记录
    sqlstr="insert into TablePM25 values({},'{}',{})" .format(n,CityName,PM25)
    cursor.execute(sqlstr)
    n+=1
    conn.commit() # 主动更新  
conn.close()  # 关闭数据库连  

from time import sleep
from selenium import webdriver

urls = ['http://www.baidu.com','http://www.wsbookshow.com','http://news.sina.com.cn/']

browser = webdriver.Chrome()
browser.maximize_window
for url in urls:
    browser.get(url) 
    sleep(3)

browser.quit()
from selenium import webdriver #导入webdriver

url='http://www.wsbookshow.com/bookshow/jc/bk/cxsj/12442.html'  #以此链接为例
browser=webdriver.Chrome()  #生成Chrome浏览器对象(结果是打开Chrome浏览器)
browser.get(url)    #在浏览器中打开url
login_form=browser.find_element_by_id("menu_1")   ##查找id="menu_1"的元素
print(login_form.text)   #显示元素内容
#browser.quit()   #退出浏览器，退出驱动程序
username=browser.find_element_by_name("username")   #查找name="username"的元素
print(username)
password=browser.find_element_by_name("pwd")  #查找name="pwd"的元素
print(password)
login_form=browser.find_element_by_xpath("//input[@name='arcID']")
print(login_form)
login_form=browser.find_element_by_xpath("//div[@id='feedback_userbox']")
print(login_form)
continue_link=browser.find_element_by_link_text('新概念美语')
print(continue_link)
continue_link=browser.find_element_by_link_text('英语')
print(continue_link)
heading1=browser.find_element_by_tag_name('h1')
print(heading1)
content=browser.find_elements_by_class_name('topbanner')
print(content)
content=browser.find_elements_by_css_selector('.topsearch')
print(content)
# print(content.get_property)
print()
browser.quit()   #退出浏览器，退出驱动程序

text = '中华'
print(type(text))#<class 'str'>
text1 = text.encode('gbk')
print(type(text1))#<class 'bytes'>
print(text1)#b'xd6xd0xbbxaa'
text2 = text1.decode('gbk')
print(type(text2))#<class 'str'>
print(text2)#中华

text4= text.encode('utf-8')
print(type(text4))#<class 'bytes'>
print(text4)#b'xe4xb8xadxe5x8dx8e'
text5 = text4.decode('utf-8')
print(type(text5))#<class 'str'>
print(text5)#中华

import requests
 
url="http://www.baidu.com"
response = requests.get(url)
content = response.text.encode('iso-8859-1').decode('utf-8')
#把网页源代码解码成Unicode编码,然后用utf-8编码
print(content)

from selenium import webdriver   # 导入webdriver模块

chrome_obj = webdriver.Chrome()              # 打开Google浏览器
chrome_obj.get("https://www.baidu.com")      # 打开 网址
print(chrome_obj.title)

from selenium import webdriver   # 导入webdriver模块

chrome_obj = webdriver.Chrome()              # 打开Google浏览器

chrome_obj.get(r"C:desktop	ext.html")      # 打开本地 html页面
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原文地址：https://www.cnblogs.com/tszr/p/10150031.html