How struts2 token prevents repeated submission

Principle: Before processing client requests, the server compares the token value contained in the request with the token value saved in the current session to check whether the request matches. After the request is processed and the information reaches the client, a new token is generated. The token value will replace the token value in the current session and be uploaded to the client. In this way, if you roll back to the submission page and submit again, the token passed by the client is inconsistent with the token value in the service, effectively preventing the submission

Conversion from: tonger http://blog.sina.com.cn/s/blog_3e0cc0540100nm7d.html