DAO Example

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public interface AnniversaryDao {   Anniversary getByYear(int years); }

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public class AnniversaryJdbcDao implements AnniversaryDao{   private static final String GET_BY_YEAR =     "SELECT * from Anniversary WHERE years = ?";   //...   public Anniversary getByYear(int years) {     //…     PreparedStatement statement = connection.prepareStatement(GET_BY_YEAR);     statement.setInt(1,years);     ResultSet rs = statement.executeQuery();     if (rs.next()){       result = new Anniversary(       rs.getInt("years"),       rs.getString("material"),       rs.getString("flowers"));     }    //  ....   return result;   } }

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public class AnniversaryJpaSeDao implements AnniversaryDao{    EntityManagerFactory emf = Persistence     .createEntityManagerFactory("JPA-03PU");     private EntityManager getEntityManager() {     return emf.createEntityManager();   }   //...   public Anniversary getByYear(int years) {     return getEntityManager().createNamedQuery(findAnniversayByYear)       .setParameter("years", years)       .getSingleResult();   } }

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@ManagedBean @RequestScoped public class AnniversaryJpaEe6Dao implements AnniversaryDao{   @¨PersistenceContext private EntityManager em;     //...   public Anniversary getByYear(int years) {     return em.createNamedQuery(findAnniversayByYear)       .setParameter("years", years)       .getSingleResult();   } }