python之回调函数

1.

备注 此示例第一部分可以执行 

后续爬虫存在问题未处理

回调函数 将一个函数的执行结果 发送给另一个函数

草稿内容:

#!/usr/bin/env python# -*- coding:utf-8 -*-#Author:xp#blog_url: http://blog.csdn.net/wuxingpu5/article/details/71209731from multiprocessing import Pool,Processimport timeimport randomimport os# def work(n):#     return n**2# if __name__ == '__main__':#     pool=Pool()#     res_l=[]#     for i in range(6):#         p=pool.apply_async(work,args=(i,))#         res_l.append(p)#     print(res_l)##     for res in res_l:#         print(res.get())  #拿到真正的执行结果'''实际示例'''# def get_page(url):#     print('正在爬取网页: %s' %url)#     time.sleep(random.randint(1,3))#     return 'xxxxxxxxxxxxx'## def parse_page(page_content):#     print('正在解析网页: %s' %page_content)#     time.sleep(1)#     page_content=os.getpid()#     return page_content## urls=[#     'baidu.com',#     'sina.com',#     'sinasdfa.com',#     'adsfsina.com',#     '123312sina.com',# ]## for url in urls:#     page_content=get_page(url)#     res=parse_page(page_content)#     print(res)# if __name__ == '__main__':#    pool=Pool()#    res_l=[]#    for url in urls:#        res=pool.apply_async(get_page,callback=parse_page)#        res_l.append(res)'''并发实际示例'''def get_page(url):    print('正在爬取网页: %s' %url)    time.sleep(random.randint(1,3))    return {'url':url}def parse_page(page_content):    time.sleep(1)    page_content['url']=os.getpid()    print('正在解析网页结果为: %s' % page_content)    return page_content# for url in urls:#     page_content=get_page(url)#     res=parse_page(page_content)#     print(res)if __name__ == '__main__':    urls = [        'baidu.com',        'sina.com',        'sinasdfa.com',        'adsfsina.com',        '123312sina.com',    ]    pool=Pool()    res_l=[]    for url in urls:        #pool.apply_async(get_page(url, ), callback=parse_page)        res=pool.apply_async(get_page(url,),callback=parse_page)        res_l.append(res)        for res in res_l:            res.get()