from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait

brguge=webdriver.Chrome()#声明驱动对象
try:
  brguge.get('https://www.baidu.com')#发送get请求
  input=brguge.find_element_by_id('kw')#找到目标
 
  input.send_keys('python')#输入python关键字
  input.send_keys(Keys.ENTER)#敲入回车
  wait=WebDriverWait(brguge,10)#等待元素加载出来
  wait.until(EC.presence_of_element_located(By.ID,'content_left'))#加载
  print(brguge.current_url)#输出搜索的路径
  print(brguge.get_cookie())#输出cookie
  print(brguge.page_source)#输出结果源代码
finally:
  brguge.close()#关闭谷歌浏览器

(from selenium import webdriver)
 
 
    brguge.find_element_by_id('q')用这个元素找id是q的元素
    brguge.find_element_by_css_selector('#q')找css样式是q的
    brguge.find_element_by_xpath('//*[ @id="q"]')三个效果一样
    brguge.find_element_by_name()通过name来查找
    brguge.find_element_by_link_text()通过link来查找
    brguge.find_element_by_partial_link_text()
    brguge.find_element_by_tag_name()
    brguge.find_element_by_class_name()通过class查找
    
    from selenium import webdriver
    from selenium.webdriver.common.by import By
    brguge.find_element(By.ID,'Q')通用查找方式

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.wait import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.chrome.options import Options
from selenium.common.exceptions import NoSuchElementException
from lxml import etree
import time, json
JD_URL_Login = "https://www.jd.com/"
class CustomizeException(Exception):
  def __init__(self, status, msg):
    self.status = status
    self.msg = msg
class JD:
  def __init__(self):
    self.browser = None
    self.__init_browser()
  def __init_browser(self):
    options = Options()
    options.add_argument("--headless")
    options.add_experimental_option('excludeSwitches', ['enable-automation'])
    # 设置为无图模式
    options.add_experimental_option("prefs", {"profile.managed_default_content_settings.images": 2})
    self.browser = webdriver.Chrome(options=options)
    # 设置浏览器最大化窗口
    self.browser.maximize_window()
    # 隐式等待时间为3s
    self.browser.implicitly_wait(3)
    self.browser.get(JD_URL_Login)
    self.wait = WebDriverWait(self.browser, 10)
  def __search_goods(self, goods):
    '''搜索商品的方法'''
    self.file = open("jd-{}.json".format(goods), "a", encoding="utf-8")
    self.wait.until(EC.presence_of_all_elements_located((By.ID, "key")))
    serach_input = self.browser.find_element_by_id("key")
    serach_input.clear()
    serach_input.send_keys(goods, Keys.ENTER)
  def __get_goods_info(self, page_source):
    '''从网页源码中获取到想要的数据'''
    selector_html = etree.HTML(page_source)
    # 商品名字 不要获取title属性，以后再改吧，最好是获取到商品名的文本内容
    goods_name = selector_html.xpath("//div[@class='gl-i-wrap']//div[contains(@class,'p-name')]/a/@title")
    # 商品价格
    goods_price = selector_html.xpath("//div[@class='gl-i-wrap']//div[@class='p-price']/strong/i/text()")
    # 商品评价数量
    comment_num_selector = selector_html.xpath("//div[@class='p-commit']/strong")
    comment_num = [selector.xpath("string(.)") for selector in comment_num_selector]
    # 商品店铺
    shop_name = selector_html.xpath("//a[@class='curr-shop']/text()")
    goods_zip = zip(goods_name, goods_price, comment_num, shop_name)
    for goods_info in goods_zip:
      dic = {}
      dic["goods_name"] = goods_info[0]
      dic["goods_price"] = goods_info[1]
      dic["comment_num"] = goods_info[2]
      dic["shop_name"] = goods_info[3]
      # print("商品名字>>:", goods_info[0])
      # print("商品价格>>:", goods_info[1])
      # print("商品评价数量>>:", goods_info[2])
      # print("商品店铺>>:", goods_info[3])
      # print("*" * 100)
      yield dic
  def __swipe_page(self):
    '''上下滑动页面，将完整的网页源码返回'''
    height = self.browser.execute_script("return document.body.scrollHeight;")
    js = "window.scrollTo(0, {});".format(height)
    self.browser.execute_script(js)
    while True:
      time.sleep(1)
      now_height = self.browser.execute_script("return document.body.scrollHeight;")
      if height == now_height:
        return self.browser.page_source
      js = "window.scrollTo({}, {});".format(height, now_height)
      self.browser.execute_script(js)
      height = now_height
  def __is_element_exists(self, xpath):
    '''检测一个xpath是否能够找到'''
    try:
      self.browser.find_element_by_xpath(xpath=xpath)
      return True
    except NoSuchElementException:
      return False
  def __click_next_page(self):
    '''点击下一页，实现翻页功能'''
    self.wait.until(EC.presence_of_all_elements_located((By.CLASS_NAME, "pn-next")))
    xpath = "//a[@class='pn-next']"
    if not self.__is_element_exists(xpath):
      raise CustomizeException(10000, "该商品访问完毕")
    self.browser.find_element_by_xpath(xpath).click()
  def __write_to_json(self, dic: dict):
    data_json = json.dumps(dic, ensure_ascii=False)
    self.file.write(data_json + "\n")
  def run(self, goods):
    self.__search_goods(goods)
    n = 1
    while True:
      print("正在爬取商品 <{}>---第{}页......".format(goods, n))
      time.sleep(3)
      html = self.__swipe_page()
      for dic in self.__get_goods_info(html):
        self.__write_to_json(dic)
      try:
        self.__click_next_page()
      except CustomizeException:
        try:
          goods = goods_list.pop(0)
          self.run(goods)
        except IndexError:
          return
      n += 1
  def __del__(self):
    self.browser.close()
    self.file.close()
if __name__ == '__main__':
  jd = JD()
  goods_list = ["纯牛奶", "酸奶", "奶茶", "床上用品", "电磁炉", "电视", "小米笔记本", "华硕笔记本", "联想笔记本", "男士洗面奶", "女士洗面奶", "沐浴露", "洗发露",
         "牙刷", "牙膏", "拖鞋", "剃须刀", "水手服", "运动服", "红龙果", "苹果", "香蕉", "洗衣液", "电饭煲"]
  try:
    goods = goods_list.pop(0)
  except IndexError:
    raise CustomizeException(20000, "goods_list不能为空")
  try:
    jd.run(goods)
  finally:
    del jd