Python爬虫包BeautifulSoup异常处理(二)

时间:2022-11-21 09:59:42

面对网络不稳定,页面更新等问题,很可能出现程序异常的问题,所以我们要对程序进行一些异常处理。大家可能觉得处理异常是一个比较麻烦的活,但在面对复杂网页和任务的时候,无疑成为一个很好的代码习惯。

网页‘404'、‘500'等问题

?
1
2
3
4
try:
    html = urlopen('http://www.pmcaff.com/2221')
  except HTTPError as e:
    print(e)

返回的是空网页

?
1
2
if html is None:
    print('没有找到网页')

目标标签在网页中缺失

?
1
2
3
4
5
6
7
8
9
10
try:
    #不存在的标签
    content = bsObj.nonExistingTag.anotherTag
  except AttributeError as e:
    print('没有找到你想要的标签')
  else:
    if content == None:
      print('没有找到你想要的标签')
    else:
      print(content)

实例

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
if sys.version_info[0] == 2:
  from urllib2 import urlopen # Python 2
  from urllib2 import HTTPError
else:
  from urllib.request import urlopen # Python3
  from urllib.error import HTTPError
from bs4 import BeautifulSoup
import sys
 
 
def getTitle(url):
  try:
    html = urlopen(url)
  except HTTPError as e:
    print(e)
    return None
  try:
    bsObj = BeautifulSoup(html.read())
    title = bsObj.body.h1
  except AttributeError as e:
    return None
  return title
 
title = getTitle("http://www.pythonscraping.com/exercises/exercise1.html")
if title == None:
  print("Title could not be found")
else:
  print(title)

以上全部为本篇文章的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。

原文链接:https://blog.csdn.net/u013007900/article/details/53819711