下面代码将根目录/映射到MainHandler，将一个URL模式/story/([0-9]+)映射到StoryHandler.
class MainHandler(tornado.web.RequestHandler):
def get(self):
self.write("You request the main page")
class StoryHandler(tornado.web.RequestHandler):
def get(self,story_id):
self.write("You requested the story " + story_id)
application = tornado.web.Application([(r"/",MainHandler),(r"/story/([0-9]+)",StoryHandler),])
使用get_argument()方法获取发送过来的参数：
class MainHandler(tornado.web.RequestHandler):
def get(self):
self.write('<html><body><form action="/" method="post">'
'<input type="text" name="message">'
'<input type="submit" value="Submit">'
'</form></body></html>')
def post(self):
self.set_header("Content-Type","text/plain")
self.write("You wrote "+ self.get_argument("message"))