User.java

package models;

import java.util.List;

import play.db.jpa.JPA;
import play.db.jpa.Model;

import javax.persistence.Query;
import javax.persistence.Table;
import javax.persistence.Entity;

@Entity
@Table(name = "users")
public class User extends Model {

	public String username;
	public String email;
	public String password;

	public String toString() {
		return username;
	}

	public static User byUsername(String username) {
		Query query = JPA.em().createQuery("from User u where u.username = :username");
		query.setMaxResults(1);
		query.setParameter("username", username);

		List<User> results = query.getResultList();
		if (results.isEmpty()) { // 
		   return null;
		}
		
		return results.get(0);
	}
}