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今天在网上看到一个多线程文件下载类，觉得编码写的不错，但是是python2的，所以改造了一下，不废话，上代码,说明：我的代码都会自己测试通过，所以可以放心使用

我的博客：

length = int(headers.get(‘Content-Length’))#用这个方法马上就能抓出你要的东西，网上没什么资料，找了1个多小时后放弃，最后看了源码才找到这个方法

'''Created on 2011-11-10@author: PaulWangDescription:''''''It is a multi-thread downloading tool    It was developed follow axel.        Author: volans        E-mail: volansw [at] gmail.com'''import sysimport osimport timeimport urllib.requestfrom threading import Thread#===============================================================================# def download(url, output, blocks=6, proxies=local_proxies)# output:输出文件的全路径，不带路径帽默认在本文件夹中生成# blocks:分几块，开几个线程# proxies:代理地址#===============================================================================local_proxies = {'http': 'http://131.139.58.200:8080'}#代理地址class AxelPython(Thread, urllib.request.FancyURLopener):    '''Multi-thread downloading class.        run() is a vitural method of Thread.    '''    def __init__(self, threadname, url, filename, ranges=0, proxies={}):        Thread.__init__(self, name=threadname)        urllib.request.FancyURLopener.__init__(self, proxies)        self.name = threadname        self.url = url        self.filename = filename        self.ranges = ranges        self.downloaded = 0    def run(self):        '''vertual function in Thread'''        try:            self.downloaded = os.path.getsize( self.filename )        except OSError:            #print 'never downloaded'            self.downloaded = 0        # rebuild start poind        self.startpoint = self.ranges[0] + self.downloaded        # This part is completed        if self.startpoint >= self.ranges[1]:            print ('Part %s has been downloaded over.' % self.filename)            return        self.oneTimeSize = 16384 #16kByte/time        print ('task %s will download from %d to %d' % (self.name, self.startpoint, self.ranges[1]))        self.addheader("Range", "bytes=%d-%d" % (self.startpoint, self.ranges[1]))        self.urlhandle = self.open( self.url )        data = self.urlhandle.read( self.oneTimeSize )        while data:            filehandle = open( self.filename, 'ab+' )            filehandle.write( data )            filehandle.close()            self.downloaded += len( data )            #print "%s" % (self.name)            #progress = u'\r...'            data = self.urlhandle.read( self.oneTimeSize )def GetUrlFileSize(url, proxies={}):    urlHandler = urllib.request.urlopen( url )    headers = urlHandler.info()    length = int(headers.get('Content-Length'))    print('Content-Length is %d' % length)    return lengthdef SpliteBlocks(totalsize, blocknumber):    blocksize = totalsize/blocknumber    ranges = []    for i in range(0, blocknumber-1):        ranges.append((i*blocksize, i*blocksize +blocksize - 1))    ranges.append(( blocksize*(blocknumber-1), totalsize -1 ))    return rangesdef islive(tasks):    for task in tasks:        if task.isAlive():            return True    return Falsedef download(url, output, blocks=6, proxies=local_proxies):    ''' paxel    '''    size = GetUrlFileSize( url, proxies )    ranges = SpliteBlocks( size, blocks )    threadname = [ "thread_%d" % i for i in range(0, blocks) ]    filename = [ "tmpfile_%d" % i for i in range(0, blocks) ]    tasks = []    for i in range(0,blocks):        task = AxelPython( threadname[i], url, filename[i], ranges[i] )        task.setDaemon( True )        task.start()        tasks.append( task )    time.sleep( 2 )    while islive(tasks):        downloaded = sum( [task.downloaded for task in tasks] )        process = downloaded/float(size)*100        show = '\rFilesize:%d Downloaded:%d Completed:%.2f%%' % (size, downloaded, process)        sys.stdout.write(show)        sys.stdout.flush()        time.sleep( 0.5 )    filehandle = open( output, 'wb+' )    for i in filename:        f = open( i, 'rb' )        filehandle.write( f.read() )        f.close()        try:            os.remove(i)            pass        except:            pass    filehandle.close()if __name__ == '__main__':    url = "http://www.pygtk.org/dist/pygtk2-tut.pdf"    output = 'pygtk2.pdf'    download( url, output, blocks=1, proxies={} )1

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