How to get the session ID returned by cookie with spring-session-data-redis

実現したいこと

Get session ID returned by cookie with spring-session-data-redis

発生している問題・分からないこと

When managing sessions using spring-session-data-redis, I think the session ID is returned in a cookie named SESSION.
（https://spring.pleiades.io/spring-session/reference/guides/boot-redis.html）
I would like to perform some processing using the session ID returned by a cookie, but I don't know how to obtain this session ID.
I referred to the following article, but it seems that the value in redis and the value returned by cookie are different values ​​due to base64 encoding, so I wonder if it is not enough to simply get the value in redis. I thought.
https://qiita.com/tttol/items/4a50ed1452488d5e6548
To be honest, this is my first time using spring-session, so I'm not sure if I understand the above.
Could you please tell me how to obtain the session ID?

該当のソースコード

特になし

試したこと・調べたこと

上記の詳細・結果

I searched on google but couldn't find it.

補足

spring boot,java