Spring cloud webUI Demo using Spring Gateway and Oauth2.

relay on microservice project : 
    spring-gateway
    spring-product-service
    ouath2
    
spring-gateway act as url transmit and authorize,webui and gateway expose to client,oauth2 and product-service hidden in private network
    benfits:
    1.webui login to gateway logpage.gateway return random access key to webui.so client cookie only contain access key.access token and fresh_token hold
        by gateway;
    2.web client do not access oauth2 directly,so can avoid lots of network attack.
    
    wait to improvement:
    1.spring gateway has no state,and i can not found any solution to do load balance or HA.
    2.i am not use oauth2 @EnableSSO anotation,so the client and gateway expire and refresh operation need to verfiy.