how to write triggers within application when using JPA with hibernate

I am a beginner in spring and hibernate and I am developing a web application using spring and I have a table with composite keys and I understand that when we use @embedded @generation will not work but I still want to make one of the keys in the composite key of my table auto increment so I want to know whether we can write triggers within the application which uses JPA with hibernate 4 and spring MVC 4 and if yes I would like to have some sample code and if no please suggest me an alternative.