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

'''遇到不懂的问题？Python学习交流群：821460695满足你的需求，资料都已经上传群文件，可以自行下载！'''

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