Doing an "IN" query with Hibernate

I have a list of IDs in a String, and want to 开发者_如何学JAVAuse Hibernate to get the rows with these IDs. TrackedItem is a Hibernate/JPA entity (sorry if I'm getting the naming mixed up here).

My code is:

String idsText = "380, 382, 386";
ArrayList<Long> ids = new ArrayList<Long>();

for (String i : idsText.split(","))
{
    ids.add(Long.getLong(i));
}

List<TrackedItem> items = TrackedItem.find("id IN (?)", ids).fetch();

But that fails: JPAQueryException occured : Error while executing query from models.TrackedItem where id IN (?): java.util.ArrayList cannot be cast to java.lang.Long

How can I make the IN part work? Thanks.

The syntax of your JPQL query is incorrect. Either use (with a positional parameter):

List<Long> ids = Arrays.asList(380L, 382L, 386L);
Query query = em.createQuery("FROM TrackedItem item WHERE item.id IN (?1)");
query.setParameterList(1, ids)
List<TrackedItem> items = query.getResultList();

Or (with a named parameter):

List<Long> ids = Arrays.asList(380L, 382L, 386L);
Query query = em.createQuery("FROM TrackedItem item WHERE item.id IN :ids");
query.setParameterList("ids", ids)
List<TrackedItem> items = query.getResultList();

Below, the relevant sections of the JPA 1.0 specification about parameters:

4.6.4.1 Positional Parameters

The following rules apply to positional parameters.

• Input parameters are designated by the question mark (?) prefix followed by an integer. For example: ?1.
• Input parameters are numbered starting from 1.
  Note that the same parameter can be used more than once in the query string and that the ordering of the use of parameters within the query string need not conform to the order of the positional parameters.

4.6.4.2 Named Parameters

A named parameter is an identifier that is prefixed by the ":" symbol. It follows the rules for identifiers defined in Section 4.4.1. Named parameters are case sensitive.

Example:

SELECT c
FROM Customer c
WHERE c.status = :stat

Section 3.6.1 describes the API for the binding of named query parameters

If you're unlucky enough to be using older non-JPA hibernate, this should work for you:

Query query = session.createQuery("FROM TrackedItem item WHERE item.id IN (:items)");
query.setParameterList("items", Arrays.asList(380L, 382L, 386L));

@SuppressWarnings("unchecked")
List<TrackedItem> results = query.list();

Even when your query executes correctly, you may face an error if your query parameter contains too many values.

One possible solution to this problem, if you are using Hibernate 5.1 or newer, is to use Session.byMultipleIds().

session
    .byMultipleIds(TrackedItem.class)
    .multiLoad(1L, 2L, 3L);

For more information, see https://thoughts-on-java.org/fetch-multiple-entities-id-hibernate/