Spring Data JPA find by embedded object property

问题:

I want to write a Spring Data JPA repository interface method signature that will let me find entities with a property of an embedded object in that entity. Does anyone know if this is possible, and if so how?

Here's my code:

@Entity
@Table(name = "BOOK_UPDATE_QUEUE", indexes = { uniqueConstraints = @UniqueConstraint(columnNames = {
        "bookId", "region" }, name = "UK01_BOOK_UPDATE_QUEUE"))
public class QueuedBook implements Serializable {

    @Embedded
    @NotNull
    private BookId bookId;

    ...

}

@Embeddable
public class BookId implements Serializable {

    @NotNull
    @Size(min=1, max=40)
    private String bookId;

    @NotNull
    @Enumerated(EnumType.STRING)
    private Region region;

    ...

}

public interface QueuedBookRepo extends JpaRepository<QueuedBook, Long> {

    //I'd like to write a method like this, but can't figure out how to search by region,
    //when region is actually a part of the embedded BookId
    Page<QueuedBook> findByRegion(Region region, Pageable pageable);

}

Can I write a query for this using Spring Data?

回答1:

This method name should do the trick:

Page<QueuedBook> findByBookIdRegion(Region region, Pageable pageable);

More info on that in the section about query derivation of the reference docs.

回答2:

The above - findByBookIdRegion() did not work for me. The following works with the latest release of String Data JPA:

Page<QueuedBook> findByBookId_Region(Region region, Pageable pageable);

回答3:

If you are using BookId as an combined primary key, then remember to change your interface from:

public interface QueuedBookRepo extends JpaRepository<QueuedBook, Long> {

to:

public interface QueuedBookRepo extends JpaRepository<QueuedBook, BookId> {

And change the annotation @Embedded to @EmbeddedId, in your QueuedBook class like this:

public class QueuedBook implements Serializable {

@EmbeddedId
@NotNull
private BookId bookId;

...