异步调用与回调机制

#!/usr/bin/python3
# -*- coding: utf-8 -*-
# @Time    : 2018/6/19 14:05
# @File    : 异步调用与回调机智.py

"""

同步调用和阻塞不一样：

同步调用不管是io型程序还是计算型程序，执行一个程序之后就是等待，

阻塞是io型特有的，因为io耗时而形成了阻塞现象

"""

# 1、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，在执行下一行代码，导致程序串行执行

# from concurrent.futures import ThreadPoolExecutor
# import time
# import 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):
#     name = shit['name']
#     size = len(shit['res'])
#     print('%s la l <%s> kg' % (name, size))
#
#
# if __name__ == '__main__':
#     pool = ThreadPoolExecutor(13)  # 限制池中数量
#     shit1 = pool.submit(la, 'alex').result()
#     weigh(shit1)
#
#     shit2 = pool.submit(la, 'wupeiqi').result()
#     weigh(shit2)
#
#     shit3 = pool.submit(la, 'yuanhao').result()
#     weigh(shit3)

# 2、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
import 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()  # 结果
    name = shit['name']
    size = len(shit['res'])
    print('%s la l <%s> kg' % (name, size))


if __name__ == '__main__':
    pool = ThreadPoolExecutor(13)  # 限制池中数量
    pool.submit(la, 'alex').add_done_callback(weigh)  # 前面任务执行完毕，自动触发weigh函数，把前面对象（pool.submit(la, 'alex')）传入
    pool.submit(la, 'wupeiqi').add_done_callback(weigh)
    pool.submit(la, 'yuanhao').add_done_callback(weigh)