JDBC无法在OpenShift上连接到mysql数据库

JDBC无法在OpenShift上连接到mysql数据库

This is incorrect:

jdbc:mysql://$OPENSHIFT_MYSQL_DB_HOST:$OPENSHIFT_MYSQL_DB_PORT/burgerjoint

That dollar sign suggests that you think a proper host and database name will
be substituted, but that’s not the case.

Code the host and database name to see that it works, then learn about
.properties files to externalize it.