CODEWITHSUNDEEP
javahibernatesessiondao
asdascascaedfa
asdascascaedfa

Reputation: 137

Proper use of session(hibernate)

Sorry for my english. I learn JavaEE and i dont know proper or not i use session in hibernate. How to use them? I use pattern DAO and hibernate. Tell my how property use session

this is HibernateUtil class

private static final SessionFactory sessionFactory;

    static {
        try{
            sessionFactory = new Configuration().configure("/app/web/landingpage/HibernateConnect/hibernate.cfg.xml").buildSessionFactory();
        }catch(Throwable ex) {
            System.out.println("Error " + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

     public static void close(Session session) {
            if (session != null) {
                try {
                    session.close();
                } catch (HibernateException ignored) {
                    System.out.print("Couldn't close Session" + ignored);
                }
            }
        }

And that class makes all operation db CategoryDaoImpl

    public class CategoryDaoImpl implements CategoryDao{
    private Session session = null;
    //get all category
    public Collection getAllCategory() {
            List categoris = new ArrayList<Category>();
            try{
                session = HibernateUtil.getSessionFactory().openSession();
                categoris = session.createCriteria(Category.class).list();
            }catch(Exception e) {
                System.out.println("getAllCategory "+ e);
            }finally{
                if(session != null && session.isOpen())
                    session.close();
            }


        return categoris;
            }
    //get category id
    public Category getCategory(int id) {

            Category cat = null;
            try {
                session = HibernateUtil.getSessionFactory().openSession();
                cat = (Category) session.load(Category.class, id);
            }catch(Exception e) {
                System.out.println("getAllCategory "+ e);
            }finally{
                if(session != null && session.isOpen())
                    session.close();
            }
            return cat;
        }

//and below few methods that use it the some way session
        }

and this servlet take results indexuser

Session session = HibernateUtil.getSessionFactory().getCurrentSession();
        session.beginTransaction();

try{
            Collection allcategory = Factory.getInstance().getCatDAO().getAllCategory();
request.setAttribute("allcategory", allcategory);
request.getRequestDispatcher("/index.jsp").forward(request, response); 
        } catch(Exception e) { 
            System.out.println(e);
        } finally{
            if(session!=null && session.isOpen())
                session.close();
        }

Upvotes: 0

Views: 307

Answers (1)

Pratik
Pratik

Reputation: 954

The main contract here is the creation of Session instances. Usually an application has a single SessionFactory instance and threads servicing client requests obtain Session instances from this factory.

The internal state of a SessionFactory is immutable. Once it is created this internal state is set. This internal state includes all of the metadata about Object/Relational Mapping.

Basically session is used to get physical connection with database. So while you performing any DB Operations it will first open Session using sessionFactory and then Session do physical connection with database and then perform your operation and after performing operation you can close it.

Session is light weight.

Upvotes: 3

Related Questions