setFirstResult and setMaxResult doesn't work well with Order By

问题

What could cause the CriteriaQuery orderBy method stop working?

Here are the implementations:

    OpenJPAEntityManager kem = OpenJPAPersistence.cast(entityManager());
    kem.getFetchPlan().clearFetchGroups();
    kem.getFetchPlan().addFetchGroup("order_search");

    CriteriaBuilder builder = kem.getCriteriaBuilder();
    CriteriaQuery<Order> query = builder.createQuery(Order.class);
    Root<Order> order = query.from(Order.class);
    query.select(order);

    Predicate main_condition = buildWhereClause(builder, query, order, target_states, orderDate_from, orderDate_to, dueDate_from, dueDate_to, username);

    query.where(main_condition);

    query.orderBy(builder.desc(order.get("orderDate")));

    TypedQuery<Order> q = entityManager().createQuery(query);

    if (firstResult != 0)
        q.setFirstResult(firstResult);
    if (maxResults != 0)
        q.setMaxResults(maxResults);

With the pagniation, when there are 15 records and we want 5 records per page, it should be:

-page1- 1 2 3 4 5 -page2- 6 7 8 9 10 -page3- 11 12 13 14 15

But now what we get here is

-page1- 1 2 3 4 5 -page2- 6 7 8 9 10 -page3- 5 4 3 2 1

the last page is always the opposite order of the first page, how come?

回答1:

Nail it, not by myself, this post is quite helpful. I did the same and now it runs like a charm. Basically need to add the primary key in to the order by criteria otherwise the pagination just totally messed.

Spend 4 hours and the solution so simple and tricky. Works on OpenJPA 2.2.2 and Oracle 11g, I guess it is a constant trick since OpenJPA 1.2 from that post.

来源：https://stackoverflow.com/questions/16629384/setfirstresult-and-setmaxresult-doesnt-work-well-with-order-by

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Spring

hibernate

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openjpa