In User
class:
@ManyToMany
@JoinTable(
name="user_page",
joinColumns = @JoinColumn(name="id_user"),
inverseJoinColumns = @JoinColumn(name="id_page")
)
public Set<Page> pages;
You can get the id's by iterating over the returned set. By default collections are lazily (i.e. only ids) loaded.
EDIT: If you don't want to map Page
for some reason, you can use @ElementCollection
like this:
@ElementCollection
@CollectionTable(name="user_page", joinColumns=@JoinColumn(name="id_user"))
@Column(name="id_page")
public Set<Long> pageIds;