o EntityManager bound to this thread. Try to annotate your action method with @play.db.jpa.Transactional

[penkee]

Hi,
I create a new class City in package models.And I use "JPA.em()" in a method in class City.
But the exception is appear.
[RuntimeException: No EntityManager bound to this thread. Try to annotate your action method with @play.db.jpa.Transactional]
As the error say,i add @play.db.jpa.Transactional on the method.no use.How can i do?