1.URLError

import urllib2

if name == ' main' :

url = 'http://www.567.com'
req = urllib2.Request(url)

try:
    response = urllib2.urlopen(req)
    #print response
    html = response.read().decode('utf-8')
    print html

except urllib2.URLError as e :
    print e.reason

结果 ：
URLError

[Errno 11004] getaddrinfo failed

2.HTTPError

import urllib2

if name == 'main' :

url = 'http://money.163.com/stocks/'
req = urllib2.Request(url)

try:
    response = urllib2.urlopen(req)
    #html = response.read()
except urllib2.HTTPError as e:
    print e.code

         结果：404

        3，URLError和HTTPError混合使用

    如果想用HTTPError和URLError一起捕获异常，那么需要将HTTPError放在URLError的前面，因为HTTPError是URLError的一个子类。如果URLError放在前面，出现HTTP异常会先响应URLError，这样HTTPError就捕获不到错误信息了。

一种方法：
import urllib2

if name == 'main' :

url = 'http://news.baidu.net'
req = urllib2.Request(url)

try :
    response = urllib2.urlopen(req)
    html = response.read().decode('utf-8')
    print html

except urllib2.HTTPError as e:
    print 'HTTPError'
    print e.code
except urllib2.URLError as e:
    print 'URLError'
    print e.reason   

    二种方法使用函数hasattr()：
    if __name__ == '__main__' :

url = 'http://www.567.com'
req = urllib2.Request(url)

try:
    response = urllib2.urlopen(req)
    html = response.read().decode('utf-8')
    print html

except urllib2.URLError as e :

    if hasattr(e,'code') :
        print 'HTTPError'
        print e.code
    elif hasattr(e,'reason') :
        print 'URLError'
        print e.reason