【下载文档: requests和lxml实例教程爬虫的方法.txt 】
requests和lxml实现爬虫的方法
如下所示：
# requests模块来请求页面
# lxml模块的html构建selector选择器(格式化响应response)
# from lxml import html
# import requests
# response = requests.get(url).content
# selector = html.formatstring(response)
# hrefs = selector.xpath('/html/body//div[@class='feed-item _j_feed_item']/a/@href')
# 以url = 'http://www.mafengwo.cn/gonglve/ziyouxing/2033.html'为例子
# python 2.7
import requests
from lxml import html
import os
# 获取首页中子页的url链接
def get_page_urls(url):
response = requests.get(url).content
# 通过lxml的html来构建选择器
selector = html.fromstring(response)
urls = []
for i in selector.xpath("/html/body//div[@class='feed-item _j_feed_item']/a/@href"):
urls.append(i)
return urls
# get title from a child's html(div[@class='title'])
def get_page_a_title(url):
'''url is ziyouxing's a@href'''
response = requests.get(url).content
selector = html.fromstring(response)
# get xpath by chrome's tool --> /html/body//div[@class='title']/text()
a_title = selector.xpath("/html/body//div[@class='title']/text()")
return a_title
# 获取页面选择器(通过lxml的html构建)
def get_selector(url):
response = requests.get(url).content
selector = html.fromstring(response)
return selector
# 通过chrome的开发者工具分析html页面结构后发现，我们需要获取的文本内容主要显示在div[@class='l-topic']和div[@class='p-section']中
# 获取所需的文本内容
def get_page_content(selector):
# /html/body/div[2]/div[2]/div[1]/div[@class='l-topic']/p/text()
page_title = selector.xpath("//div[@class='l-topic']/p/text()")
# /html/body/div[2]/div[2]/div[1]/div[2]/div[15]/div[@class='p-section']/text()
page_content = selector.xpath("//div[@class='p-section']/text()")
return page_title,page_content
# 获取页面中的图片url地址
def get_image_urls(selector):
imagesrcs = selector.xpath("//img[@class='_j_lazyload']/@src")
return imagesrcs
# 获取图片的标题
def get_image_title(selector, num)
# num 是从2开始的
url = "/html/body/div[2]/div[2]/div[1]/div[2]/div["+num+"]/span[@class='img-an']/text()"
if selector.xpath(url) is not None:
image_title = selector.xpath(url)
else:
image_title = "map"+str(num) # 没有就起一个
return image_title
# 下载图片
def downloadimages(selector,number):
'''number是用来计数的'''
urls = get_image_urls()
num = 2
amount = len(urls)
for url in urls:
image_title = get_image_title(selector, num)
filename = "/home/WorkSpace/tour/words/result"+number+"/+"image_title+".jpg"
if not os.path.exists(filename):
os.makedirs(filename)
print('downloading %s image %s' %(number, image_title))
with open(filename, 'wb') as f:
f.write(requests.get(url).content)
num += 1
print "已经下载了%s张图" %num
# 入口，启动并把获取的数据存入文件中
if __name__ =='__main__':
url = 'http://www.mafengwo.cn/gonglve/ziyouxing/2033.html'
urls = get_page_urls(url)
# turn to get response from html
number = 1
for i in urls:
selector = get_selector(i)
# download images
downloadimages(selector,number)
# get text and write into a file
page_title, page_content = get_page_content(selector)
result = page_title+'\n'+page_content+'\n\n'
path = "/home/WorkSpace/tour/words/result"+num+"/"
if not os.path.exists(filename):
os.makedirs(filename)
filename = path + "num"+".txt"
with open(filename,'wb') as f:
f.write(result)
print result
到此就结束了该爬虫，爬取页面前一定要认真分析html结构，有些页面是由js生成，该页面比较简单，没涉及到js的处理，日后的随笔中会有相关分享
以上这篇requests和lxml实现爬虫的方法就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持中文源码网。
