future

import   tornado.ioloop
import   tornado.web
from  tornado.concurrent import Future
import  time
from  tornado import gen


#fututre模块进行异步的请求操作



class  MainHandler(tornado.web.RequestHandler):
    @gen.coroutine
    def  get(self, *args, **kwargs):
        import time
        global   future
        future=Future()
        future.add_done_callback(self.done)#加一个返回值回来，当执行完成的时候，就执行下面的函数部分
        yield   future


    def   done(self,*args,**kwargs):
        print('执行完成')
        self.write('完成')
        self.finish()


class  IndexHnadler(tornado.web.RequestHandler):
    def  get(self, *args, **kwargs):
        future.set_result(None)##设置返回值回来
        self.write('index')

def  run():
    application=tornado.web.Application([
        (r'/main',MainHandler),
        (r'/index', IndexHnadler),
    ])
    ##seting配置
    application.listen(8000)
    tornado.ioloop.IOLoop.instance().start()
run()