Python爬虫入门：urllib中的异常处理

简介

urllib库的error模块定义了由request模块产生的异常。如果有问题，request模块会抛出error模块中定义的异常。

URLError

URLError是error异常模块的基类，request产生的异常都可以捕获。

from urllib import request,error
try:
	response = request.urlopen('https://www.qq.com/index.html')
except error.URLError as e:
	print(e.reason)

HTTPError

HTTPError是URLError的子类，专门处理HTTP请求错误，比如认证失败等。

简单实例

from urllib import request,error
try:
	response = request.urlopen('https://www.qq.com/index.html')
except error.HTTPError as e:
	print(e.reason,e.code, e.headers, sep='\n')

优化写法

from urllib import request,error
try:
	response = request.urlopen('https://www.qq.com/index.html')
except error.HTTPError as e:
	print(e.reason,e.code, e.headers, sep='\n')
except error.URLError as e:
	print(e.reason)
else:
	print('Request Successfully')

reason可以不是字符串而是一个对象

超时的情况下，异常的reason就是一个socket.timeout对象。

import socket
from urllib import request,error

try:
	response = request.urlopen('https://www.baidu.com', timeout=0.01)
except error.URLError as e:
	if isinstance(e.reason, socket.timeout):
		print('TIME OUT')
else:
	print('Request Successfully')