程序代码：

class S(SGMLParser):
    '''取链接的'''
  
def pachong(url):
    a=urllib2.urlopen(url)
    parser=S()
    parser.feed(a.read())
    b=parser.urls  #HTML里取得的链接列表
    if b:return b
def main():
    while True:
        url=q.get()
        c=pachong(url)
        if c:
            for url in c:
                print url
                q.put(url)
q=Queue()
q.put('http://www.')
for i in range(10):
    t=threading.Thread(target=main)
    t.start()