tornado接收ajax的post请求报错WARNING:tornado.access:405 OPTI

2xhr.js?ec6c:172 OPTIONS http://localhost:8888/add 405 (Method Not Allowed)/#/:1 Access to XMLHttpRequest at ‘http://localhost:8888/add‘ from origin ‘http://localhost:8080‘ has been blocked by CORS policy: Response to preflight request doesn‘t pass access control check: No ‘Access-Control-Allow-Origin‘ header is present on the requested resource.

import tornado.ioloop
import tornado.web
import json


class AddHandler(tornado.web.RequestHandler):

    def initialize(self):
        # self.request.method = ‘POST‘
        # print(self.request.method,type(self.request.method))
        self.set_default_header()

    def get(self):
        self.write("U get story id is ")

    def post(self):
        self.write(json.dumps({"sum": ‘rrrrrr‘}))

    def set_default_header(self):
        print("setting headers!!!")
        self.set_header(‘Access-Control-Allow-Origin‘,‘*‘)
        # self.set_header(‘Access-Control-Allow-Origin‘,‘http://localhost:8080‘)
        # self.set_header(‘Access-Control-Allow-Headers‘,‘X-Requested-With‘)
        self.set_header(‘Access-Control-Allow-Headers‘,‘*‘)
        self.set_header(‘Access-Control-Allow-Methods‘,‘GET,POST,PUT,DELETE,PATCH,OPTIONS‘)
        self.set_header(‘Content-Type‘,‘application/json; charset=UTF-8‘)
        self.set_header(‘Access-Control-Allow-Headers‘,‘Content-Type‘)

    def options(self):
        pass


application = tornado.web.Application([
    (r"/add",AddHandler),])

if __name__ == "__main__":
    application.listen(8888)
    tornado.ioloop.IOLoop.instance().start()