[Python]网络爬虫（三）：使用cookiejar管理cookie 以及模拟登录知乎

待我称王封你为后i 2022-06-06 00:23 2486阅读 0赞

大家好哈，上一节我们研究了一下爬虫的异常处理问题，那么接下来我们一起来看一下Cookie的使用。

为什么要使用Cookie呢？

Cookie，指某些网站为了辨别用户身份、进行session跟踪而储存在用户本地终端上的数据（通常经过加密）

比如说有些网站需要登录后才能访问某个页面，在登录之前，你想抓取某个页面内容是不允许的。那么我们可以利用python3的cookiejar模块来保存cookie信息，然后模拟登录。

在此之前呢，我们必须先介绍一个opener的概念。

## 1.Opener ##

当你获取一个URL你使用一个opener。在前面，我们都是使用的默认的opener，也就是urlopen。它是一个特殊的opener，可以理解成opener的一个特殊实例，传入的参数仅仅是url，data，timeout。

如果我们需要用到Cookie，只用这个opener是不能达到目的的，所以我们需要创建更一般的opener来实现对Cookie的设置。

## 2.Cookiejar ##

cookiejar模块的主要作用是提供可存储cookie的对象，以便于与urllib模块配合使用来访问Internet资源。Cookiejar模块非常强大，我们可以利用本模块的CookieJar类的对象来捕获cookie并在后续连接请求时重新发送，比如可以实现模拟登录功能。该模块主要的对象有CookieJar、FileCookieJar、MozillaCookieJar、LWPCookieJar。

它们的关系：CookieJar —-派生—->FileCookieJar  —-派生—–>MozillaCookieJar和LWPCookieJar

### 1）获取Cookie保存到变量 ###

首先，我们先利用CookieJar对象实现获取cookie的功能，存储到变量中，先来感受一下

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       3 
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       5 
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       6 
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       9 
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       10 
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       11 
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       12 
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       13 
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    <div style="padding-right: 0px; padding-left: 0px; margin: 0px; white-space: pre; overflow: visible; tab-size: 4; background: none !important; border: none !important; padding-top: 5px !important; padding-bottom: 3px !important; line-height: 15px !important;"> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">from urllib import request</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">from urllib import parse</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">from http import cookiejar</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <br> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(184, 92, 0) !important;">#声明一个CookieJar对象实例来保存cookie</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">cookie</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> </span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;">=</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> </span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">cookiejar</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">.</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">CookieJar</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">(</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">)</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(184, 92, 0) !important;">#利用urllib库中的request的HTTPCookieProcessor对象来创建cookie处理器</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">handler</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;">=</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"><span style="color:#002d7a;">request</span></span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">.</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">HTTPCookieProcessor</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">(</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">cookie</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">)</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(184, 92, 0) !important;">#通过handler来构建opener</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">opener</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> </span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;">=</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> </span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;"><span style="color:#002d7a;">request</span></span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">.</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">build_opener</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">(</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">handler</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">)</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(184, 92, 0) !important;">#此处的open方法同urllib的urlopen方法，也可以传入request</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">response</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> </span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;">=</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> </span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">opener</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">.</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">open</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">(</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(221, 17, 68) !important;">'http://www.baidu.com'</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">)</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: bold !important;">for</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> </span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">item </span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: bold !important;">in</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> </span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">cookie</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;">:</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;">&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">print</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> (</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(221, 17, 68) !important;">'Name = '</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;">+</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">item</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">.</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">name)</span> 
     </div> 
     <div style="font-family: inherit; background: 0px center; border: 0px; padding: 0px 5px; margin: 0px; height: inherit; word-break: break-all; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; white-space: pre-wrap !important;"> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: teal !important;">&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important;">print</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;"> (</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(221, 17, 68) !important;">'Value = '</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 111, 224) !important;">+</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">item</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(51, 51, 51) !important;">.</span> 
      <span style="font-family: inherit; height: inherit; font-size: inherit !important; line-height: inherit !important; font-weight: inherit !important; color: rgb(0, 45, 122) !important;">value)</span> 
     </div> 
    </div></td> 
  </tr> 
 </tbody> 
</table>

我们使用以上方法将cookie保存到变量中，然后打印出了cookie中的值，运行结果如下

###     ###

### 2）保存Cookie到文件 ###

在上面的方法中，我们将cookie保存到了cookie这个变量中，如果我们想将cookie保存到文件中该怎么做呢？这时，我们就要用到

FileCookieJar这个对象了，**建立LWPCookieJar实例，可以存Set-Cookie3类型的文件。而MozillaCookieJar类是存为'.txt'格式的文件.**在这里我们使用它的子类MozillaCookieJar来实现Cookie的保存

关于最后save方法的两个参数在此说明一下：

官方解释如下：

> *ignore\_discard: save even cookies set to be discarded. *
> 
> *ignore\_expires: save even cookies that have expiredThe file is overwritten if it already exists*

由此可见，ignore\_discard的意思是即使cookies将被丢弃也将它保存下来，ignore\_expires的意思是如果在该文件中cookies已经存在，则覆盖原文件写入，在这里，我们将这两个全部设置为True。运行之后，cookies将被保存到cookie.txt文件中，我们查看一下内容，附图如下

[![QQ截图20150215215136][QQ_20150215215136]][QQ_20150215215136]

使用LWPCookieJar来保存cookie:

filename ='cookie'

cookie = cookiejar.LWPCookieJar(filename)

使用的时候直接load。

###  3）从文件中获取Cookie并访问 ###

那么我们已经做到把Cookie保存到文件中了，如果以后想使用，可以利用下面的方法来读取cookie并访问网站，感受一下

设想，如果我们的 cookie.txt 文件中保存的是某个人登录百度的cookie，那么我们提取出这个cookie文件内容，就可以用以上方法模拟这个人的账号登录百度。

###  4）利用cookie模拟网站登录 ###

下面我们以知乎为例，利用cookie实现模拟登录，来感受一下cookie大法吧！

#!/usr/bin/env/python
    #encoding: UTF-8
    
    import re
    import requests
    import http.cookiejar
    from PIL import Image
    import time
    import json
    
    headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 '
                             '(KHTML, like Gecko) Chrome/57.0.2987.98 Safari/537.36',
               "Host": "www.zhihu.com",
               "Referer": "https://www.zhihu.com/",
               }
    # 建立一个会话，可以把同一用户的不同请求联系起来；直到会话结束都会自动处理cookies
    session = requests.Session()
    # 建立LWPCookieJar实例，可以存Set-Cookie3类型的文件。
    # 而MozillaCookieJar类是存为'/.txt'格式的文件
    session.cookies = http.cookiejar.LWPCookieJar("cookie")
    # 若本地有cookie则不用再post数据了
    try:
        session.cookies.load(ignore_discard=True)
    except IOError:
        print('Cookie未加载！')
    
    
    def get_xsrf():
        """
        获取参数_xsrf
        """
        response = session.get('https://www.zhihu.com', headers=headers)
        html = response.text
        get_xsrf_pattern = re.compile(r'<input type="hidden" name="_xsrf" value="(.*?)"')
        _xsrf = re.findall(get_xsrf_pattern, html)[0]
        return _xsrf
    
    
    def get_captcha():
        """
        获取验证码本地显示
        返回你输入的验证码
        """
        t = str(int(time.time() * 1000))
        captcha_url = 'http://www.zhihu.com/captcha.gif?r=' + t + "&type=login"
        response = session.get(captcha_url, headers=headers)
        with open('cptcha.gif', 'wb') as f:
            f.write(response.content)
        # Pillow显示验证码
        im = Image.open('cptcha.gif')
        im.show()
        captcha = input('本次登录需要输入验证码： ')
        return captcha
    
    
    def login(username, password):
        """
        输入自己的账号密码，模拟登录知乎
        """
        # 检测到11位数字则是手机登录
        if re.match(r'\d{11}$', username):
            url = 'http://www.zhihu.com/login/phone_num'
            data = {'_xsrf': get_xsrf(),
                    'password': password,
                    'remember_me': 'true',
                    'phone_num': username
                    }
        else:
            url = 'https://www.zhihu.com/login/email'
            data = {'_xsrf': get_xsrf(),
                    'password': password,
                    'remember_me': 'true',
                    'email': username
                    }
        # 若不用验证码，直接登录
        result = session.post(url, data=data, headers=headers)
        # 打印返回的响应，r = 1代表响应失败，msg里是失败的原因
        # loads可以反序列化内置数据类型，而load可以从文件读取
        if (json.loads(result.text))["r"] == 1:
            # 要用验证码，post后登录
            data['captcha'] = get_captcha()
            result = session.post(url, data=data, headers=headers)
            print((json.loads(result.text))['msg'])
            # 保存cookie到本地
        session.cookies.save(ignore_discard=True, ignore_expires=True)
    
    
    def isLogin():
        # 通过查看用户个人信息来判断是否已经登录
        url = "https://www.zhihu.com/settings/profile"
        # 禁止重定向，否则登录失败重定向到首页也是响应200
        login_code = session.get(url, headers=headers, allow_redirects=False).status_code
        if login_code == 200:
            return True
        else:
            return False
    
    
    if __name__ == '__main__':
        if isLogin():
            print('您已经登录')
        else:
            account = input('输入账号：')
            secret = input('输入密码：')
            login(account, secret)

以上程序的原理如下

创建一个带有cookie的opener，在访问登录的URL时，将登录后的cookie保存下来，然后利用这个cookie来访问其他网址。

如登录之后才能查看的成绩查询呀，本学期课表呀等等网址，模拟登录就这么实现啦，是不是很酷炫？

好，小伙伴们要加油哦！我们现在可以顺利获取网站信息了，接下来就是把网站里面有效内容提取出来，下一节我们去会会正则表达式！

[QQ_20150215215136]: /images/20220606/e0774c9c658642f0a4c5f5354c9273f2.png