Spring Data JPA Lazy加载注释为Eager的集合

Question

I have a project that is using Spring Data repositories to auto generate some of its methods. One such method is one that accepts a couple parameters and returns a list of books. In the repository, that method looks like this:

List<Book> findBySellerFlagTrueAndPublishedState(PublishedState state);

However, when I use that method, it seems like hibernate is lazy loading properties of the books which are annotated as FetchType.EAGER. Also, I have the same issue when I build the query myself using JPA's Criteriabuilder. When I use the default findOne(Long id) method, those properties are eagerly loaded.

I'm using JPA 2.0, and am using Hibernate as the implementation.

Here's my annotations on one of the relationships I'm having this issue with:

@ManyToMany(fetch = FetchType.EAGER)
@JoinTable(name="BOOK_THEME", 
joinColumns=@JoinColumn(name="BOOK_ID", referencedColumnName="BOOK_ID"),
inverseJoinColumns=@JoinColumn(name="THEME_ID", referencedColumnName="THEME_ID"))
@OrderColumn(name="THEME_SEQUENCE")
private List<Theme> themes;

The getters and setters are just standard, and it's a unidirectional relationship (there are no books in Theme ).

I think it must be an issue with how I have my annotations set up. Does anyone know what I have wrong?

Answer 1

I discovered that annotating the themes with @Fetch(FetchMode.SUBSELECT) accomplished my goals, but a better solution was to set hibernate.default_batch_fetch_size in the hibernate properties. That way I could set it to some number (I chose 100) and it would improve the performance of all lazy and eager fetching for many relationships at once.