JPQL and date comparison (constraint in the query)

My Application model object contains a date field (time stamp):

@Entity
@Table(name = "M开发者_开发百科YTABLE")
public class Application {

   private Date timeStamp;
   ...
}

I'm trying to construct a JPQL query that would select all applications that were changed today (i.e. their time stamp was changed anytime today). What is the best way to do this?

There is no perfect way with standard JPQL, JPQL doesn't provide Date arithmetic functions. But your provider might provide extensions (e.g. Hibernate and EclipseLink do). Or use a native SQL.