Alibaba cloud RDS exception during pool initialization

Alibaba cloud database RDS edition Communications link failure hole

This is a big hole .
Before 11 Every month is fine , I don't know why this is happening now ??
The project is normally in idea Run successfully in , Pack it up jar Packages or war The following errors will be reported when the package is released , Cause the project connection to fail .

log The key in the log log by ：
ERROR com.zaxxer.hikari.pool.HikariPool - HikariPool-1 - Exception during pool initialization.
com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

I found many ways in Baidu , Setting up useSSL=false
#serverTimezone: Asia/Shanghai
# useUnicode: true
# allowPublicKeyRetrieval: true
And set the parameters of cloud database wait_timeout and innactive_timeout The value of is larger ,
No success ！

The final solution ：

I Directly in Alibaba cloud RDS The management console logs into the database , then tomcat-ui Interface manager app Start this war package , actually start succeed （ You can't retry many times before ）（ direct restart tomcat Service is OK , I am here manager app It starts because I have opened this interface at this time ）
Running success chart ：
sign ： Started SpringsunApplication in 13.924 seconds (JVM running for 41505.291)

This is really a big hole now …
Maybe Alibaba cloud database rules have changed ？？？（ I have never touched this setting ,11 It was all right before the month , released war Packages can also run ）
The only operation I think of is that I shut down Alibaba cloud server at the weekend , Recently, my server has also been frequently detected for external attacks , Baidu for a while , I found that it was hacked into a timed script , Lead to CPU Often occupy too much , Thus, it is detected by Alibaba cloud as an external attack , The one in the scheduled task has been deleted and sealed IP.

But I don't think it involves Alibaba cloud database when I shut down Alibaba cloud server ？ These two are independent services （ The database instance is always running ）

And I may every start once tomcat, I need to log in to Alibaba cloud database panel ？？

Anyway, If someone sees or knows that there is a better solution , Please leave a message and tell me ~