實例：百度搜索，結(jié)果列表翻頁查詢
解決問題：解決selenium driver獲取web頁面元素時，元素過期問題
思路1：獲取所有“頁面翻頁鏈接”元素，然后遍歷元素并點擊
# -*- coding: utf-8 -*-
from selenium import webdriver
import time
if __name__ == "__main__":
driver = webdriver.Firefox()
driver.maximize_window()
driver.get('http://www.baidu.com')
driver.implicitly_wait(5)
driver.find_element_by_id('kw1').send_keys('selenium')
driver.find_element_by_id('su1').click()
page = driver.find_element_by_id('page')
pages = page.find_elements_by_tag_name('a') #查找所有翻頁跳轉(zhuǎn)鏈接
#設(shè)置滾動條位置為底部
js = 'document.documentElement.scrollTop=10000'
for each in pages:
driver.execute_script(js) #拖動滾動條到底部
each.click()
driver.execute_script(js)
time.sleep(3)
driver.quit()
結(jié)果：點擊第3頁時，程序出錯
selenium.common.exceptions.StaleElementReferenceException: Message: u'Element not found in the cache - perhaps the page has changed since it was looked up' ; Stacktrace:
即在cache中找不到元素，可能是在元素被找到之后頁面變換了。 這說明，當(dāng)前頁面發(fā)生跳轉(zhuǎn)之后，存在cache中的與這個頁面相關(guān)的元素也被清空了
思路2：基于思路1的錯誤結(jié)果分析>先獲取每個頁面數(shù)，然后每次點擊某個頁面，跳轉(zhuǎn)后重新獲取下一個頁面翻頁鏈接，然后點擊，循環(huán)。。
# -*- coding: utf-8 -*-
from selenium import webdriver
import time
if __name__ == "__main__":
driver = webdriver.Firefox()
driver.maximize_window()
driver.get('http://www.baidu.com')
driver.implicitly_wait(5)
driver.find_element_by_id('kw1').send_keys('selenium')
driver.find_element_by_id('su1').click()
page = driver.find_element_by_id('page')
pages = page.find_elements_by_tag_name('a')
js = 'document.documentElement.scrollTop=10000'
total = len(pages)
has_pre_page = False
page_num = 0
for i in range(total):
driver.execute_script(js)
pn=10
page_num = page_num + 1 #設(shè)置頁面號
one_page = driver.find_element_by_css_selector('p[id="page"]>a:nth-of-type('+str(page_num)+')')
one_page.click()
