to build:
mvn clean package
then place
demotest-1.war
in tomcat webapps
then open url:
localhost:8080/demotest-1
localhost:8080/demotest-1/hello
before mvn clean install in SpringConfig.java
for mysql: jdbc:mysql://localhost:3306/vebinar?useSll=false
for mariaDB: jdbc:mariadb://localhost:3306/vebinar?useSll=false