python3通过selenium爬虫获取到dj商品的实例代码
先给大家介绍下python3 selenium使用
其实这个就相当于模拟人的点击事件来连续的访问浏览器。如果你玩过王者荣耀的话在2016年一月份的版本里面就有一个bug。
安卓手机下载一个按键精灵就可以在冒险模式里面设置按键,让手机自动玩闯关,一局19个金币,一晚上就一个英雄了。不过
程序员也不是吃素的。给一个星期设置了大概4000金币上限。有兴趣的可以去试试。(注:手机需要root)
进入正题:
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
在写之前需要下载selenium模块
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
下面是一些selenium模块的基本用法
查找元素
单个元素
(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
多个元素(find_elements)加了个s
他会以列表的形式打印出来
brguge.find_elements_by_css_selector('.service-bd li')css样式为li的元素
brguge.find_elements(By.css_selector,'.service-bd li')两个作用一样
(利用索引就可以获取单个或多个元素了)
元素交互操作(获取元素然后再给他指令)
选择输入框 --》send_keys('输入文字')--》clear()清空输入框--在输入别的--》找到搜索--》click(点击)
input.clear()清空按钮
交互动作(将动作附加到动作链中串行执行)
switch_to_frame('iframeResult')
用css样式分别找到两个要交互
调用ActionChains(调用谷歌的)
drag_and_drop(source,target)第一个到第二个上面
perform()
下面看下python3通过selenium爬虫获取到dj商品的实例代码。
具体代码如下所示:
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
总结
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