redis 异步读写，2.0改版后操作代码

`
from tornado import ioloop, web
import json
import aioredis

settings = {
"debug" : True,
"redis":"redis://:@127.0.0.1:6379/0",
}

class Home(web.RequestHandler):
def prepare(self):
self.json_argument = {}
# if self.request.method.lower() in ("get", "post", "put", "delete", "patch"):
# if self.request.headers.get("Content-Type").lower() == "application/json":
# self.json_argument = json.loads(self.request.body)

async def get(self):
    # 2.0之后，aioredis 提供了 from_url 方法，直接从 url 中创建连接
    # redis = await aioredis.create_connection(self.application.settings["redis"])
    # redis = await aioredis.create_connection(self.application.settings["redis"])
    # await redis.execute("setex", "name", 60, "chen",)
    # data = await redis.get("name")
    # print(data.decode())
    # self.write(data.decode())

    redis = aioredis.from_url(self.application.settings["redis"])
    async with redis.client() as conn:
        await conn.setex("name", 60, "chen")
        data = await conn.get("name")
        print(data.decode())
        self.write(data.decode())

async def redis_pool():
# Redis client bound to pool of connections (auto-reconnecting).
redis = aioredis.from_url(
"redis://localhost", encoding="utf-8", decode_responses=True
)
await redis.set("my-key", "value")
val = await redis.get("my-key")
print(val)

def make_app():
return web.Application(handlers=[
(r"/", Home)],
**settings,
)

if name == 'main':
app = make_app()
app.listen(8888)
ioloop.IOLoop.current().start()

`