本次爬取用到的知识点有:

seleniumpymysqlpyquery

正文

分析目标网站打开某宝首页, 输入"男装"后点击"搜索", 则跳转到"男装"的搜索界面.空白处"右击"再点击"检查"审查网页元素, 点击"Network".

1) 找到对应的URL, URL里的参数正是Query String Parameters的参数, 且请求方式是GET

2) 我们请求该URL得到内容就是"Response"里的内容, 那么点击它来确认信息.

3) 下拉看到"男装"字样, 那么再往下找, 并没有发现有关"男装"的商品信息.

4) 任意复制一个商品信息, 空白处右击再点击"查看网页源代码", 在源码查找该商品, 即可看到该商品的信息.

5) 对比网页源代码和"Response"响应内容, 发现源代码<script>..........</script>中的商品信息被替换, 这便是采用了JS加密

6) 如果去请求上面的URL, 得到的则是加密过的信息, 这时就可以利用Selenium库来模拟浏览器, 进而得到商品信息.

获取单个商品界面

请求网站

# -*- coding: utf-8 -*-from selenium import webdriver #从selenium导入浏览器驱动browser = webdriver.Chrome() #声明驱动对象, 即Chrome浏览器def get_one_page(): '''获取单个页面''' browser.get("") #请求网站

输入"男装", 在输入之前, 需要判断输入框是否存在, 如果存在则输入"男装", 不存在则等待显示成功.

# -*- coding: utf-8 -*-from selenium import webdriver from selenium.webdriver.common.by import By #导入元素定位方法模块from selenium.webdriver.support.ui import WebDriverWait #导入等待判断模块from selenium.webdriver.support import expected_conditions as EC #导入判断条件模块browser = webdriver.Chrome() def get_one_page(): '''获取单个页面''' browser.get("")  input = WebDriverWait(browser,10).until( #等待判断 EC.presence_of_element_located((By.CSS_SELECTOR,"#q"))) #若输入框显示成功,则获取,否则等待 input.send_keys("男装") #输入商品名称

下一步就是点击"搜索"按钮, 按钮具有属性: 可点击, 那么加入判断条件.

# -*- coding: utf-8 -*-from selenium import webdriver from selenium.webdriver.common.by import By from selenium.webdriver.support.ui import WebDriverWait from selenium.webdriver.support import expected_conditions as EC browser = webdriver.Chrome() def get_one_page(): '''获取单个页面''' browser.get("")  input = WebDriverWait(browser,10).until(  EC.presence_of_element_located((By.CSS_SELECTOR,"#q"))) # input.send_keys("男装")  button = WebDriverWait(browser,10).until( #等待判断 EC.element_to_be_clickable((By.CSS_SELECTOR,"#J_TSearchForm > div.search-button > button"))) #若按钮可点击, 则获取, 否则等待 button.click() 

获取总的页数, 同样加入等待判断.

# -*- coding: utf-8 -*-​import refrom selenium import webdriverfrom selenium.common.exceptions import TimeoutExceptionfrom selenium.webdriver.common.by import Byfrom selenium.webdriver.support.ui import WebDriverWaitfrom selenium.webdriver.support import expected_conditions as ECbrowser = webdriver.Chrome()def get_one_page(): '''获取单个页面''' browser.get("") input = WebDriverWait(browser, 10).until( EC.presence_of_element_located((By.CSS_SELECTOR, "#q"))) input.send_keys("男装") button = WebDriverWait(browser, 10).until( EC.element_to_be_clickable( (By.CSS_SELECTOR, "#J_TSearchForm > div.search-button > button"))) button.click()  pages = WebDriverWait(browser, 10).until( # 等待判断 EC.presence_of_element_located( (By.CSS_SELECTOR, "#mainsrp-pager > div > div > div > div.total"))) # 若总页数加载成功,则获取总页数,否则等待  return pages.textdef main(): pages = get_one_page() print(pages)if __name__ == '__main__': main()

打印出来的不是我们想要的结果, 利用正则表达式获取, 最后再利用try...except捕捉异常

# -*- coding: utf-8 -*-import refrom selenium import webdriver from selenium.common.exceptions import TimeoutException from selenium.webdriver.common.by import By from selenium.webdriver.support.ui import WebDriverWait from selenium.webdriver.support import expected_conditions as EC browser = webdriver.Chrome() def get_one_page(): '''获取单个页面''' try: browser.get("")  input = WebDriverWait(browser,10).until( EC.presence_of_element_located((By.CSS_SELECTOR,"#q")))  input.send_keys("男装")  button = WebDriverWait(browser,10).until( EC.element_to_be_clickable((By.CSS_SELECTOR,"#J_TSearchForm > div.search-button > button")))  button.click()  pages = WebDriverWait(browser,10).until( EC.presence_of_element_located((By.CSS_SELECTOR,"#mainsrp-pager > div > div > div > div.total")))  return pages.text except TimeoutException: return get_one_page() #如果超时,继续获取def main(): pages = get_one_page() pages = int(re.compile("(\d+)").findall(pages)[0]) #采用正则表达式提取文本中的总页数 print(pages)if __name__ == '__main__': main()​

关于Selenium的更多内容,可参看官方文档

获取多个商品界面

采用获取"到第 页"输入框方式, 切换到下一页, 同样是等待判断

需要注意的是, 最后要加入判断: 高亮是否是当前页

def get_next_page(page): try: input = WebDriverWait(browser, 10).until(  EC.presence_of_element_located((By.CSS_SELECTOR, "#mainsrp-pager > div > div > div > div.form > input"))) # 若输入框加载成功,则获取,否则等待 input.send_keys(page) # 输入页码 button = WebDriverWait(browser, 10).until(  EC.element_to_be_clickable((By.CSS_SELECTOR, "#mainsrp-pager > div > div > div > div.form > span.btn.J_Submit"))) # 若按钮可点击,则获取,否则等待 button.click() # 点击按钮 WebDriverWait(browser,10).until( EC.text_to_be_present_in_element((By.CSS_SELECTOR,"#mainsrp-pager > div > div > div > ul > li.item.active > span"),str(page))) # 判断高亮是否是当前页 except TimeoutException: # 超时, 继续请求 return get_next_page(page)def main(): pages = get_one_page() pages = int(re.compile("(\d+)").findall(pages)[0]) for page in range(1,pages+1): get_next_page(page)if __name__ == '__main__': main()

获取商品信息

首先, 判断信息是否加载成功, 紧接着获取源码并初始化, 进而解析.

需要注意的是, 在"get_one_page"和"get_next_page"中调用之后, 才可执行

def get_info(): """获取详情""" WebDriverWait(browser,20).until(EC.presence_of_element_located(( By.CSS_SELECTOR,"#mainsrp-itemlist .items .item"))) #判断商品信息是否加载成功 text = browser.page_source #获取网页源码 html = pq(text) #初始化网页源码 items = html('#mainsrp-itemlist .items .item').items() #采用items方法会得到生成器 for item in items: #遍历每个节点对象 data = [] image = item.find(".pic .img").attr("src") #用find方法查找子孙节点,用attr方法获取属性名称 price = item.find(".price").text().strip().replace("\n","") #用text方法获取文本,strip()去掉前后字符串,默认是空格 deal = item.find(".deal-cnt").text()[:-2] title = item.find(".title").text().strip() shop = item.find(".shop").text().strip() location = item.find(".location").text() data.append([shop, location, title, price, deal, image]) print(data)

保存到MySQL数据库

def save_to_mysql(data): """存储到数据库""" # 创建数据库连接对象 db= pymysql.connect(host = "localhost",user = "root",password = "password",port = 3306, db = "spiders",charset = "utf8") # 获取游标 cursor = db.cursor() #创建数据库 cursor.execute("CREATE TABLE IF NOT EXISTS {0}(shop VARCHAR(20),location VARCHAR(10),title VARCHAR(255),price VARCHAR(20),deal VARCHAR(20), image VARCHAR(255))".format("男装")) #SQL语句 sql = "INSERT INTO {0} values(%s,%s,%s,%s,%s,%s)".format("男装") try: #传入参数sql,data if cursor.execute(sql,data): #插入数据库 db.commit() print("********已入库**********") except: print("#########入库失败#########") #回滚,相当什么都没做 db.rollback() #关闭数据库 db.close()

完整代码

import reimport pymysqlfrom selenium import webdriver from selenium.common.exceptions import TimeoutExceptionfrom selenium.webdriver.common.by import By from selenium.webdriver.support.ui import WebDriverWait from selenium.webdriver.support import expected_conditions as EC from pyquery import PyQuery as pqbrowser = webdriver.Chrome() def get_one_page(name): '''获取单个页面''' print("-----------------------------------------------获取第一页-------------------------------------------------------") try: browser.get("")  input = WebDriverWait(browser,10).until(  EC.presence_of_element_located((By.CSS_SELECTOR,"#q")))  input.send_keys(name)  button = WebDriverWait(browser,10).until(  EC.element_to_be_clickable((By.CSS_SELECTOR,"#J_TSearchForm > div.search-button > button")))  button.click()  pages = WebDriverWait(browser,10).until(  EC.presence_of_element_located((By.CSS_SELECTOR,"#mainsrp-pager > div > div > div > div.total")))  print("----即将解析第一页信息----") get_info(name) print("----第一页信息解析完成----") return pages.text except TimeoutException: return get_one_page(name) def get_next_page(page,name): """获取下一页""" print("---------------------------------------------------正在获取第{0}页----------------------------------------".format(page)) try: input = WebDriverWait(browser, 10).until( EC.presence_of_element_located((By.CSS_SELECTOR, "#mainsrp-pager > div > div > div > div.form > input")))  input.send_keys(page)  button = WebDriverWait(browser, 10).until( EC.element_to_be_clickable((By.CSS_SELECTOR, "#mainsrp-pager > div > div > div > div.form > span.btn.J_Submit")))  button.click()  WebDriverWait(browser,10).until( EC.text_to_be_present_in_element((By.CSS_SELECTOR,"#mainsrp-pager > div > div > div > ul > li.item.active > span"),str(page)))  print("-----即将解析第{0}页信息-----".format(page)) get_info(name) print("-----第{0}页信息解析完成-----".format(page)) except TimeoutException:  return get_next_page(page,name)def get_info(name): """获取详情"""  WebDriverWait(browser,20).until(EC.presence_of_element_located(( By.CSS_SELECTOR,"#mainsrp-itemlist .items .item")))  text = browser.page_source  html = pq(text)  items = html('#mainsrp-itemlist .items .item').items()  for item in items:  data = [] image = item.find(".pic .img").attr("src")  price = item.find(".price").text().strip().replace("\n","")  deal = item.find(".deal-cnt").text()[:-2] title = item.find(".title").text().strip() shop = item.find(".shop").text().strip() location = item.find(".location").text() data.append([shop, location, title, price, deal, image]) for dt in data: save_to_mysql(dt,name)def save_to_mysql(data,name): """存储到数据库""" db= pymysql.connect(host = "localhost",user = "root",password = "password",port = 3306, db = "spiders",charset = "utf8") cursor = db.cursor() cursor.execute("CREATE TABLE IF NOT EXISTS {0}(shop VARCHAR(20),location VARCHAR(10),title VARCHAR(255),price VARCHAR(20),deal VARCHAR(20), image VARCHAR(255))".format(name)) sql = "INSERT INTO {0} values(%s,%s,%s,%s,%s,%s)".format(name) try: if cursor.execute(sql,data): db.commit() print("********已入库**********") except: print("#########入库失败#########") db.rollback() db.close()def main(name): pages = get_one_page(name) pages = int(re.compile("(\d+)").findall(pages)[0]) for page in range(1,pages+1): get_next_page(page,name)if __name__ == '__main__': name = "男装" main(name)