Changing Persistence Unit (JPA)

Question

I’m developing a Java SE application using JPA.
At runtime, the application needs to connect to different databases, each one with the same structure but different data (for example one database for each company).
I can’t define in advance different Persistence Units in the persistence.xml file, because the user decides when and how many db will create.
Is there some way to manipulate de persistence.xml file at runtime (for example change the PU name) without recompile the application?
Thanks for your help.

Answer 1

Yes, I found the solution.
I use the method to obtain a EntityManager with a HashMap parameter, where I can put the name of the database. Example:
String dbURL = "jdbc:mysql://localhost:3306/" + "myDataBaseName";
HashMap<String, String> propMap;
propMap = new HashMap<String, String>();
propMap.put("toplink.jdbc.url", dbURL);
EntityManager em = Persistence.createEntityManagerFactory("myPU", propMap).createEntityManager();
This overrides de property in the persistence.xml file.
Hope it help you.
Regards