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我想使用urllib和urllib2从特定的网站刮一些数据。urllib2.urlopen失败，而urllib.urlopen工作在相同的URL
现在urllib主要用于读取和处理数据，而urllib2的代码段主要用于读取和存储数据。
外部网站经历了一些变化，虽然urllib代码部分继续工作urllib2部分简单地龙骨翻转。
所以我做了一些检查，发现urllib2.urlopen（URL）总是返回一个空白字符串，而urllib.urlopen（URL）总是正常工作。
我进一步挖掘，双方的urllib和urllib的模块启用调试日志记录：
>>> response2 =urllib2.urlopen('http://www.xxxxxxxxltd.com/web/guest/attendancelist')
send: 'GET /web/guest/attendancelist HTTP/1.1\r\nAccept-Encoding: identity\r\nHost: www.xxxxxxxxltd.com\r\nConnection: close\r\nUser-Agent: Python-urllib/2.6\r\n\r\n'
reply: 'HTTP/1.1 302 Moved Temporarily\r\n'
header: Server: nginx/0.7.67
header: Date: Thu, 28 Nov 2013 19:12:28 GMT
header: Transfer-Encoding: chunked
header: Connection: close
header: Location: http://www.xxxxxxxxplc.com/web/guest/attendancelist
send: 'GET /web/guest/attendancelist HTTP/1.1\r\nAccept-Encoding: identity\r\nHost: www.xxxxxxxxplc.com\r\nConnection: close\r\nUser-Agent: Python-urllib/2.6\r\n\r\n'
reply: 'HTTP/1.1 301 Moved Permanently\r\n'
header: Server: Apache-Coyote/1.1
header: Location: /home/new/attendancelist.jsp
header: Content-Length: 0
header: Date: Thu, 28 Nov 2013 19:12:26 GMT
header: Connection: close
send: 'GET /home/new/attendancelist.jsp HTTP/1.1\r\nAccept-Encoding: identity\r\nHost: www.xxxxxxxxplc.com\r\nConnection: close\r\nUser-Agent: Python-urllib/2.6\r\n\r\n'
reply: 'HTTP/1.1 200 OK\r\n'
header: Server: Apache-Coyote/1.1
header: Set-Cookie: JSESSIONID=F02B1F76CCCF6F41BE48951F6E1A6205; Path=/home
header: Content-Type: text/html;charset=utf-8
header: Content-Length: 0
header: Date: Thu, 28 Nov 2013 19:12:26 GMT
header: Connection: close
而且....
>>> html3=urllib.urlopen('http://www.xxxxxxxxltd.com/web/guest/attendancelist')
send: 'GET /web/guest/attendancelist HTTP/1.0\r\nHost: www.xxxxxxxxltd.com\r\nUser-Agent: Python-urllib/1.17\r\n\r\n'
reply: 'HTTP/1.1 302 Moved Temporarily\r\n'
header: Server: nginx/0.7.67
header: Date: Thu, 28 Nov 2013 19:10:36 GMT
header: Connection: close
header: Location: http://www.xxxxxxxxplc.com/web/guest/attendancelist
send: 'GET /web/guest/attendancelist HTTP/1.0\r\nHost: www.xxxxxxxxplc.com\r\nUser-Agent: Python-urllib/1.17\r\n\r\n'
reply: 'HTTP/1.1 301 Moved Permanently\r\n'
header: Server: Apache-Coyote/1.1
header: Location: /home/new/attendancelist.jsp
header: Content-Length: 0
header: Date: Thu, 28 Nov 2013 19:10:34 GMT
header: Connection: close
send: 'GET /home/new/attendancelist.jsp HTTP/1.0\r\nHost: www.xxxxxxxxplc.com\r\nUser-Agent: Python-urllib/1.17\r\n\r\n'
reply: 'HTTP/1.1 200 OK\r\n'
header: Server: Apache-Coyote/1.1
header: Set-Cookie: JSESSIONID=8CFB903B80C42CA3DA37EDF90D84FF99; Path=/home
header: Content-Type: text/html;charset=utf-8
header: Date: Thu, 28 Nov 2013 19:10:35 GMT
header: Connection: close
如可辨，在urllib2的连接流有显著更多的连接标题（其中之一是Connection标题，其值为Close）。
任何人都可以帮助找到为什么urllib2无法检索数据，而urllib模块运作良好。
我确定它与Connection标题有关，但我想要某种确认和思考过程解释。
谢谢。
我在日志中看到的唯一区别是Accept-encoding头。哪些内容是由urllib返回的？ p.ex.它是纯html还是gziped？ – alko
真正的问题是，尽管urllib返回页面的实际内容（纯文本被正确地抓取和格式化），但urllib2响应不会返回任何数据（这通过将'Content-Length'值设置为0来确认urllib2头信息 –