[code]Tornado实现异步代码

# coding=utf-8


import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.web
import tornado.httpclient
import tornado.gen
from tornado.concurrent import run_on_executor
from concurrent.futures import ThreadPoolExecutor
import time


class SleepHandler(tornado.web.RequestHandler):
    executor = ThreadPoolExecutor(2)

    @tornado.web.asynchronous
    @tornado.gen.coroutine
    def get(self):
        """
        若是要实现异步并且该请求需要等待执行结果则加入yield
        否则可以将yield去掉，程序会继续往下执行
        """
        res = yield self.sleep()
        self.write("when i sleep %s s" % res)
        self.finish()

    @run_on_executor
    def sleep(self):
        time.sleep(5)
        return 5

class NormalHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("normal handler")


if __name__ == "__main__":
    app = tornado.web.Application(handlers=[
            (r"/sleep", SleepHandler), (r"/normal", NormalHandler)])
    http_server = tornado.httpserver.HTTPServer(app)
    http_server.listen(8888)
    tornado.ioloop.IOLoop.instance().start()