python批量检查url的失效性

#!/usr/bin/python
# -*- coding:utf-8 -*-
 
import urllib2
from urllib2 import URLError
 
result_url=[]
count=0
not_200=0
f=open("img1.txt","r")
img_not_200=open("img_not_200.txt","w+")
 
for line in f:
    count+=1
    print "on scanning ",count
    try:
    	response=urllib2.urlopen(line)
    except URLError, e:
    	if hasattr(e,'reason'): #stands for URLError
    		print "can not reach a server,writing..."
    		result_url.append(line)
    		not_200+=1
    		img_not_200.write(line)
    		print "write url success!"
    	elif hasattr(e,'code'): #stands for HTTPError
    		print "find http error, writing..."
    		result_url.append(line)
    		not_200+=1
    		img_not_200.write(line)
    		print "write url success!"
    	else: #stands for unknown error
    		print "unknown error, writing..."
    		result_url.append(line)
    		not_200+=1
    		img_not_200.write(line)
    		print "write url success!"
    else:
    	#print "url is reachable!"
    	#else 中不用再判断 response.code 是否等于200,若没有抛出异常，肯定返回200,直接关闭即可
    	response.close()
    finally:
    	pass
 
print "scanning over,total",count,"; did not response 200:",not_200
f.close()
img_not_200.close()