Tomcat can't connect to mariadb when we deployed the java-web project in centos7

i can share my experience with you. i also face same type of problem. in my situation i use tomcat, Mysql, centOS.

after long time R&D i found three problem.

• One is i use MySql 8 server. it has different driver class "com.mysql.cj.jdbc.Driver"
• 2nd one is CentOS firewall dose not allowing access to the MySQL server on port 3306/tcp from host 127.0.0.1
• last one is Mysql 8 default security future. (user level privilege.)

you should check all of this issue in your case.....