python3中urlopen()和get()区别
爬虫里面，我们不可避免的要用urllib中的urlopen()和requests.get()方法去请求或获取一个网页的内容,这里面的区别在于urlopen打开URL网址，url参数可以是一个字符串url或者是一个Request对象，返回的是http.client.HTTPResponse对象.http.client.HTTPResponse对象大概包括read()、readinto()、getheader()、getheaders()、fileno()、msg、version、status、reason、debuglevel和closed函数，其实一般而言使用read()函数后还需要decode()函数，这里一个巨大的优势就是：返回的网页内容实际上是没有被解码或的，在read()得到内容后通过指定decode()函数参数，可以使用对应的解码方式。
而requests.get()方法请求了站点的网址，然后打印出了返回结果的类型，状态码，编码方式，Cookies等内容
from urllib.request import urlopen
import requests
data_get=requests.get("https://www.baidu.com").content.decode("utf-8")
html_url=urlopen("https://www.baidu.com")
data_url=html_url.read()
with open("data_get.html","w") as f:
f.write(data_get)
print(data_get)
print("------------------------\n")
print(data_url)
with open("data_url.html","wb") as f:
f.write(data_url)data_get.html如下：
<html>
<head>
<meta http-equiv=content-type content=text/html;charset=utf-8>
<meta http-equiv=X-UA-Compatible content=IE=Edge>
<meta content=always name=referrer>
<link rel=stylesheet type=text/css href=https://ss1.bdstatic.com/5eN1bjq8AAUYm2zgoY3K/r/www/cache/bdorz/baidu.min.css>
<title>百度一下，你就知道title>
head>
<body link=#0000cc>
<div id=wrapper>
<div id=head>
<div class=head_wrapper>
<div class=s_form>
<div class=s_form_wrapper>
<div id=lg>
<img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129>
div>
<form id=form name=f action=//www.baidu.com/s class=fm>
<input type=hidden name=bdorz_come value=1>
<input type=hidden name=ie value=utf-8>
<input type=hidden name=f value=8>
<input type=hidden name=rsv_bp value=1>
<input type=hidden name=rsv_idx value=1>
<input type=hidden name=tn value=baidu>
<span class="bg s_ipt_wr">
<input id=kw name=wd class=s_ipt value maxlength=255 autocomplete=off autofocus=autofocus>
span><span class="bg s_btn_wr">
<input type=submit id=su value=百度一下 class="bg s_btn" autofocus>
span>
form>
div>
div>
<div id=u1>
<a href=http://news.baidu.com name=tj_trnews class=mnav>新闻a>
<a href=https://www.hao123.com name=tj_trhao123 class=mnav>hao123a>
<a href=http://map.baidu.com name=tj_trmap class=mnav>地图a>
<a href=http://v.baidu.com name=tj_trvideo class=mnav>视频a>
<a href=http://tieba.baidu.com name=tj_trtieba class=mnav>贴吧a>
<noscript>
<a href=http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u=http%3A%2F%2Fwww.baidu.com%2f%3fbdorz_come%3d1 name=tj_login class=lb>登录a>
noscript>
<script>document.write('encodeURIComponent(window.location.href+ (window.location.search === "" ? "?" : "&")+ "bdorz_come=1")+ '" name="tj_login" class="lb">登录');
script>
<a href=//www.baidu.com/more/ name=tj_briicon class=bri style="display: block;">更多产品a>
div>
div>
div>
<div id=ftCon>
<div id=ftConw>
<p id=lh>
<a href=http://home.baidu.com>关于百度a>
<a href=http://ir.baidu.com>About Baidua> p>
<p id=cp>©2017 Baidu
<a href=http://www.baidu.com/duty/>使用百度前必读a>
<a href=http://jianyi.baidu.com/ class=cp-feedback>意见反馈a> 京ICP证030173号
<img src=//www.baidu.com/img/gs.gif>
p>
div>
div>
div>
body>
html>
data_url如下：
<html>
<head>
<script>
location.replace(location.href.replace("https://","http://"));
script>
head>
<body>
<noscript><meta http-equiv="refresh" content="0;url=http://www.baidu.com/">noscript>
body>
html>