关于urllib2中的Keep-Alive

http://www.nabble.com/-CPyUG:41451--%E5%85%B3%E4%BA%8Eurllib2%E4%B8%AD%E7%9A%84Keep-Alive%E5%8F%8A%E8%AF%B7%E6%95%99%E5%A5%BD%E7%94%A8%E7%9A%84http%E5%AE%A2%E6%88%B7%E7%AB%AF%E5%8C%85-td15706978.html