前言

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作者： Star_Zhao

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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 webdriverfrom 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 webdriverfrom 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(                                                        #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()                                                                                   #点击按钮

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 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'''    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()

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("data-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

# -*- coding: utf-8 -*-import reimport pymysqlfrom 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 ECfrom 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("data-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)