使用与jpa相同的模式将NetBeans平台应用程序连接到不同的DBMS

I need to make an application where the user can configure some connection parameters like server and DBMS (specifically MySQL, MSSQL and Oracle). As long as the database schema is the same, but not the server in order to use the servers already working in the client's intranet, I'm trying to find a way to force jpa use the parameters set by the user and make the transaction. Any idea? I need to make an application where the user ca