Question

在我的Spring Boot / Data / JPA 2.1应用程序中，我有一个以下实体：

@Entity
@NamedEntityGraph(name = "graph.CardCategoryLevel", attributeNodes = { @NamedAttributeNode("cardCategory"), @NamedAttributeNode("level") })
@Table(name = "card_categories_levels")
public class CardCategoryLevel extends BaseEntity implements Serializable {

    @Id
    @SequenceGenerator(name = "card_categories_levels_id_seq", sequenceName = "card_categories_levels_id_seq", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "card_categories_levels_id_seq")
    private Long id;

    @OneToOne
    @JoinColumn(name = "card_category_id")
    private CardCategory cardCategory;

    @OneToOne
    @JoinColumn(name = "level_id")
    private Level level;

    @Column(name = "card_drop_rate")
    private Float cardDropRate;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "cardCategoryLevel")
    private List<Card> cards = new ArrayList<Card>();
....
}

和Spring Data CardCategoryLevelRepository：

@Repository
public interface CardCategoryLevelRepository extends JpaRepository<CardCategoryLevel, Long> {

    @Override
    @EntityGraph(value = "graph.CardCategoryLevel", type = EntityGraphType.FETCH)
    Page<CardCategoryLevel> findAll(Pageable pageable);

}

基于CardCategoryLevelRepository.findAll(Pageable pageable)，我可以通过分页和排序检索所有CardCategoryLevel。

现在我不知道如何将过滤应用到这种方法中。例如，我需要有可能按CardCategoryLevel或/和CardCategory或/和Level过滤cardDropRate。如何将过滤功能注入CardCategoryLevelRepository.findAll(Pageable pageable)方法或者可能是一个新的类似方法？

Answer 1

使用QueryDSL和实体图实现。现在我可以使用QueryDSL谓词应用过滤（也请投票给这个BUG ：https://jira.spring.io/browse/DATAJPA-684）：

@Repository
public interface CardCategoryLevelRepository extends JpaRepository<CardCategoryLevel, Long>, QueryDslPredicateExecutor<CardCategoryLevel>, CardCategoryLevelRepositoryCustom {

    @Override
    @EntityGraph(value = "graph.CardCategoryLevel", type = EntityGraphType.LOAD)
    List<CardCategoryLevel> findAll(Predicate predicate);

....
}

public interface CardCategoryLevelRepositoryCustom {

    Page<CardCategoryLevel> findAll(Predicate predicate, Pageable pageable);

}

public class CardCategoryLevelRepositoryImpl extends SimpleJpaRepository<CardCategoryLevel, Long> implements CardCategoryLevelRepositoryCustom {

    private final EntityManager entityManager;
    private final EntityPath<CardCategoryLevel> path;
    private final PathBuilder<CardCategoryLevel> builder;
    private final Querydsl querydsl;

    /**
     * Workaround, must be removed once fixed
     * https://jira.spring.io/browse/DATAJPA-684
     * http://stackoverflow.com/questions/36043665/querydsl-query-specified-join-fetching-but-the-owner-of-the-fetched-associati
     * 
     * @param entityManager
     */
    @Autowired
    public CardCategoryLevelRepositoryImpl(EntityManager entityManager) {
        super(CardCategoryLevel.class, entityManager);

        this.entityManager = entityManager;
        this.path = SimpleEntityPathResolver.INSTANCE.createPath(CardCategoryLevel.class);
        this.builder = new PathBuilder<>(path.getType(), path.getMetadata());
        this.querydsl = new Querydsl(entityManager, builder);
    }

    /**
     * Workaround, must be removed once fixed
     * https://jira.spring.io/browse/DATAJPA-684
     * http://stackoverflow.com/questions/36043665/querydsl-query-specified-join-fetching-but-the-owner-of-the-fetched-associati
     */
    @Override
    public Page<CardCategoryLevel> findAll(Predicate predicate, Pageable pageable) {
        JPAQuery countQuery = createQuery(predicate);
        JPAQuery query = (JPAQuery) querydsl.applyPagination(pageable, createQuery(predicate));

        query.setHint(EntityGraph.EntityGraphType.LOAD.getKey(), entityManager.getEntityGraph("graph.CardCategoryLevel"));

        Long total = countQuery.count();
        List<CardCategoryLevel> content = total > pageable.getOffset() ? query.list(path) : Collections.<CardCategoryLevel> emptyList();

        return new PageImpl<>(content, pageable, total);
    }

    private JPAQuery createQuery(Predicate predicate) {
        return querydsl.createQuery(path).where(predicate);
    }

}

存储库方法中的Spring数据过滤

1 个答案: