python学习笔记（二十二）爬虫基础（2）：模拟浏览器，ajax动态爬取，爬取数据写入文件、图片爬虫

目录

一、将爬取到的数据写入文件

二、模拟浏览器

三、动态ajax爬取

四、图片爬虫

---

 

一、将爬取到的数据写入文件

import urllib.request

urllib.request.urlretrieve("http://www.baidu.com",filename=r"F:\untitled\爬虫\爬虫\file\file2.html")

#urlretrieve在执行的过程中会产生缓存
#清除缓存
urllib.request.urlcleanup()

二、模拟浏览器

import urllib.request
import random

url = "http://www.baidu.com"
'''
#模拟请求头
headers = {
	"Accept":"application/json,text/javascript,q=0.01",
	"X-Requested-With":"XMLHttpRequest",
	"User-Agent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.204 Safari/537.36",
	"Content-Type":"application/x-www-form-urlencoded;charset=utf-8"
}

#设置一个请求体
req = urllib.request.Request(url,headers=headers)
#发起请求
response = urllib.request.urlopen(req)
data = response.read().decode("utf-8")
print(data)
'''
agentList = [
	"Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_8; en-us) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50",
	"Mozilla/5.0 (Windows; U; Windows NT 6.1; en-us) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50",
	"Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0",
	"Mozilla/5.0 (Windows NT 6.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1",
	"Opera/9.80 (Windows NT 6.1; U; en) Presto/2.8.131 Version/11.11",
	"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; SE 2.X MetaSr 1.0; SE 2.X MetaSr 1.0; .NET CLR 2.0.50727; SE 2.X MetaSr 1.0)"
]
agentStr = random.choice(agentList)
req = urllib.request.Request(url)
#向请求体里添加User-Agent
req.add_header("User-Agent",agentStr)
response = urllib.request.urlopen(req)
print(response.read().decode("utf-8"))

三、动态ajax爬取

import urllib.request
import ssl
import json

def ajaxCrawler(url):
	headers = {
		"User-Agent":"Mozilla/5.0 (Windows; U; Windows NT 6.1; en-us) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50"
	}
	req = urllib.request.Request(url,headers=headers)

	#使用ssl创建未验证的上下文
	context = ssl._create_unverified_context()
	response = urllib.request.urlopen(req,context=context)

	jsonStr = response.read().decode("utf-8")
	jsonData = json.loads(jsonStr)


	return jsonData


# url = "https://movie.douban.com/j/chart/top_list?type=17&interval_id=100%3A90&action=&start=20&limit=20"
# info = ajaxCrawler(url)
# print(info)

for i in (1,11):
	url = "https://movie.douban.com/j/chart/top_list?type=17&interval_id=100%3A90&action=&start="+str(i*20)+"&limit=20"
	info = ajaxCrawler(url)
	print(len(info))

四、图片爬虫

import urllib.request
import re
import os

def imgCrawler(url,toPath):
	headers = {
		'User-agent':'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-us) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50'
	}

	req = urllib.request.Request(url,headers=headers)
	response = urllib.request.urlopen(req)
	HtmlStr = response.read().decode("utf-8")
	# with open(r"F:\学习存放\untitled\爬虫\img\img.html","wb") as f:
	# 	f.write(HtmlStr)

	pat = r'<img src="//(.*?)"/>'
	#pat = r'<img src="//(.*?)"/>'
	re_image = re.compile(pat, re.S)
	imgList = re_image.findall(HtmlStr)
	num = 1

	for imageUrl in imgList:
		path = os.path.join(toPath, str(num)+".jpg")
		num += 1
		#把图片下载到本地存储
		urllib.request.urlretrieve("http://"+imageUrl,filename=path)

url = 'https://search.yhd.com/c0-0/k%25E6%25AD%25BB%25E5%25BA%2593%25E6%25B0%25B4/'
toPath =r'F:\untitled\爬虫\img'
imgCrawler(url,toPath)