本程序以爬取 'http://httpbin.org/post' 为例

格式:

  导入urllib.request

  导入urllib.parse

  数据编码处理,再设为utf-8编码:  bytes(urllib.parse.urlencode({'word': 'hello'}), encoding = 'utf-8')

  打开爬取的网页: response = urllib.request.urlopen('网址', data = data)

  读取网页代码: html = response.read()

  打印:

      1.不decode 

      print(html) #爬取的网页代码会不分行,没有空格显示,很难看

      2.decode

      print(html.decode()) #爬取的网页代码会分行,像写规范的代码一样,看起来很舒服

  查询请求结果:

      a. response.status # 返回 200:请求成功  404:网页找不到,请求失败

      b. response.getcode() # 返回 200:请求成功  404:网页找不到,请求失败



1.不decode的程序如下:

import urllib.request
import urllib.parsse

data = bytes(urllib.parse.urlencode({'word': 'hello'}), encoding = 'utf-8')
response = urllib.request.urlopen(' data = data )
html = response.read()

print(html)
print("------------------------------------------------------------------")
print("------------------------------------------------------------------")
print(response.status)
print(response.getcode())


运行结果:

blob.png


2.带decode的程序如下:

import urllib.request
import urllib.parsse

data = bytes(urllib.parse.urlencode({'word': 'hello'}), encoding = 'utf-8')
response = urllib.request.urlopen(' data = data )
html = response.read()

print(html.decode())
print("------------------------------------------------------------------")
print("------------------------------------------------------------------")
print(response.status)
print(response.getcode())


运行结果:

{
  "args": {}, 
  "data": "", 
  "files": {}, 
  "form": {
    "word": "hello"
  }, 
  "headers": {
    "Accept-Encoding": "identity", 
    "Connection": "close", 
    "Content-Length": "10", 
    "Content-Type": "application/x-www-form-urlencoded", 
    "Host": "httpbin.org", 
    "User-Agent": "Python-urllib/3.4"
  }, 
  "json": null, 
  "origin": "106.14.17.222", 
  "url": "http://httpbin.org/post"
}

------------------------------------------------------------------
------------------------------------------------------------------
200
200


为什么要用bytes转换?

因为

data = urllib.parse.urlencode({'word': 'hello'}) ##没有用bytes
response = urllib.request.urlopen('http://httpbin.org/post', data = data )
html = response.read()

错误提示:

Traceback (most recent call last):
  File "/usercode/file.py", line 15, in <module>
    response = urllib.request.urlopen('http://httpbin.org/post', data = data )
  File "/usr/lib/python3.4/urllib/request.py", line 153, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib/python3.4/urllib/request.py", line 453, in open
    req = meth(req)
  File "/usr/lib/python3.4/urllib/request.py", line 1104, in do_request_
    raise TypeError(msg)
TypeError: POST data should be bytes or an iterable of bytes. It cannot be of type str.

由此可见,post方式需要将请求内容用二进制编码。

class bytes([source[, encoding[, errors]]])

    Return a new “bytes” object, which is an immutable sequence of integers in the range <= 256bytes is an immutable version of bytearray– it has the same non-mutating methods and the same indexing and slicing behavior.

Accordingly, constructor arguments are interpreted as for bytearray().