TypedQuery<x> returns vector of Object[] instead of list of x-type object

问题

I have a method:

public List<Timetable> getTimetableTableForRegion(String id) {
        List<Timetable> timetables;
        TypedQuery<Timetable> query = em_read.createQuery("SELECT ..stuff.. where R.id = :id", Timetable.class).setParameter("id", Long.parseLong(id));
        timetables = query.getResultList();

        return timetables;
    }

which returns this:

so, what am I missing in order to return a list of Timetable's?

回答1:

ok, so, ..stuff.. part of my JPQL contained an inner join to other table. Even through in SELECT there were selected fields just from one table, which was used as type - Timetable, Eclipslink was unable to determine if this fields are part of that entity and instead of returning list of defined entity returned list of Object[].

So in conclusion: Use @OneToMany/@ManyToOne mappings (or flat table design) and query just for ONE table in your JPQL to be able to typize returned entities.

回答2:

Not sure it might be something is looking for, but I had similar problem and converted Vector to ArrayList like this:

    final ArrayList<YourClazz> results = new ArrayList<YourClazz>();;
    for ( YourClazzkey : (Vector<YourClazz>) query.getResultList() )
    {
        results.add(key);
    }

来源：https://stackoverflow.com/questions/23202730/typedqueryx-returns-vector-of-object-instead-of-list-of-x-type-object