多线程实例：

 

# -*- coding: utf-8 -*-

import requests

import urllib

import os

import threading

import datetime

 

 

gImageList = []

gCondition = threading.Condition()

 

 

class Producer(threading.Thread):

    def run(self):

        global gImageList

        global gCondition

 

        print('%s started' % threading.current_thread())

        imgs = download_wallpaper_list()

 

        gCondition.acquire()

        for i in imgs:

            if 'downloadUrl' in i:

                gImageList.append(i['downloadUrl'])

        print('%s: produced finished. Left: %s' % (threading.current_thread(),  len(gImageList)))

        gCondition.notify_all()

        gCondition.release()

 

        

 

class Consumer(threading.Thread):

    def run(self):   

        print('%s started' % threading.current_thread())

        while True:

            global gImageList

            global gCondition

            

            gCondition.acquire()

            print('%s: trying to download image. Queue length is %d' % (threading.current_thread(), len(gImageList)))

            while len(gImageList) == 0:

                gCondition.wait()

                print('%s: waken up. Queue length is %d' % (threading.current_thread(), len(gImageList)))

            url = gImageList.pop()

            gCondition.release()

            _download_image(url)

 

 

def _download_image(url, folder='image'):

    if not os.path.isdir(folder):

        os.mkdir(folder)

    print('downloading %s' %  url)

    def _fname(s):

         return os.path.join(folder, os.path.split(url)[1])

 

    urllib.urlretrieve(url, _fname(url))

 

def download_wallpaper_list():

    url = 'http://image.baidu.com/data/imgs'

    params = {

        'pn': 1,

        'rn': 20,

        'col': '壁纸',

        'tag': '国家地理',

        'tag3': '',

        'width': 1600,

        'height': 900,

        'ic': 0,

        'ie': 'utf8',

        'oe': 'utf-8',

        'image_id': '',

        'fr': 'channel',

        'p': 'channel',

        'from': 1,

        'app': 'img.browse.channel.wallpaper',

        't': '0.016929891658946872'

    }

    r = requests.get(url, params=params)

    imgs = r.json()['imgs']

    print('%s: totally %d images' % (threading.current_thread(), len(imgs)))

    return imgs

 

 

if __name__ == '__main__':

    Producer().start()

 

    for i in range(1):                       ##改变这个1就能改变线程数

        Consumer().start()

 

来自为知笔记(Wiz)