提交任务的两种方式。
同步调用：提交完任务后，就在原地等待任务执行完毕，拿到结果，再执行下一行代码，导致程序是串行执行
异步调用：提交完任务后，不等待任务执行完毕
from concurrent.futures import ThreadPoolExecutor import time,random def la(name): print(‘%s is laing‘%name) time.sleep(random.randint(3,5)) res = random.randint(7,13)*‘#‘ return {‘name‘:name,‘res‘:res} def weigh(shit): shit = shit.result() # 异步回掉时，处理接收到的对象 name = shit[‘name‘] size = len(shit[‘res‘]) print(‘%s 拉了 《%s》kg‘%(name,size)) if __name__ ==‘__main__‘: pool = ThreadPoolExecutor(13) # 同步调用 # shit1 = pool.submit(la,‘alex‘).result() # weigh(shit1) # shit2 = pool.submit(la, ‘huhao‘).result() # weigh(shit2) # shit3 = pool.submit(la, ‘zhanbin‘).result() # weigh(shit3) # 异步调用 pool.submit(la, ‘alex‘).add_done_callback(weigh) pool.submit(la, ‘huhao‘).add_done_callback(weigh) pool.submit(la, ‘zhanbin‘).add_done_callback(weigh)
简单网页爬虫示例：
import requests,time from concurrent.futures import ThreadPoolExecutor def get(url): print(‘get url‘,url) response = requests.get(url) time.sleep(3) return {‘url‘:url,‘content‘:response.text} def parse(res): res = res.result() print(‘%s parse res is %s‘%(res[‘url‘],len(res[‘content‘]))) if __name__ == ‘__main__‘: urls = [ ‘http://www.cnblogs.com/stin‘, ‘https://www.python.org‘, ‘https://www.openstack.org‘, ] pool = ThreadPoolExecutor(2) for url in urls: pool.submit(get,url).add_done_callback(parse)