python网络爬虫（1）静态网页抓取

获取响应内容：

import requests
r=requests.get('http://www.santostang.com/')
print(r.encoding)
print(r.status_code)
print(r.text)

获取编码，状态（200成功，4xx客户端错误，5xx服务器相应错误），文本，等。

定制Request请求

传递URL参数

key_dict = {'key1':'value1','key2':'value2'}
r=requests.get('http://httpbin.org/get',params=key_dict)
print(r.url)
print(r.text)

定制请求头

headers={'user-agent':'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 SE 2.X MetaSr 1.0','Host':'www.santostang.com'}
r=requests.get('http://www.santostang.com',headers=headers)
print(r.status_code)

发送POST请求

POST请求发送表单信息，密码不显示在URL中，数据字典发送时自动编码为表单形式。

key_dict = {'key1':'value1','key2':'value2'}
r=requests.post('http://httpbin.org/post',data=key_dict)
print(r.url)
print(r.text)

超时并抛出异常

r=requests.get('http://www.santostang.com/',timeout=0.11)

　　

获取top250电影数据

import requests
import myToolFunction
from bs4 import BeautifulSoup
 
def get_movies():
    headers={'user-agent':'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 SE 2.X MetaSr 1.0','Host':'movie.douban.com'}
    movie_list=[]
    for i in range(10):
        link='https://movie.douban.com/top250'
        key_dict = {'start':i*25,'filter':''}
        r=requests.get(link,params=key_dict)
        #print(r.text)
        print(r.status_code)
        print(r.url)
 
        soup=BeautifulSoup(r.text,'lxml')
        div_list=soup.find_all('div', class_='hd')
        for each in div_list:
            movie=each.a.span.text.strip()+'\n'
            movie_list.append(movie)
        pass
    return movie_list
 
def storFile(data,fileName,method='a'):
    with open(fileName,method,newline ='') as f:
        f.write(data)
        pass
    pass
 
movie_list=get_movies()
for str in movie_list:
    myToolFunction.storFile(str, 'movie top250.txt','a')
    pass