java - Spring Data Jpa项目使用ManyToMany关系时的生成查询

Question

我有以下实体映射:

@Entity
@Table(name = "books")
public class Book implements Serializable {
    @ManyToMany
    @JoinTable(name="books2categories",
    joinColumns=@JoinColumn(name="book_id"),
    inverseJoinColumns=@JoinColumn(name="category_id"))
    Collection<Category> categories;

...

@Entity
@Table(name = "categories")
public class Category implements Serializable {
    @ManyToMany(mappedBy="categories")
    private Collection<Book> books;

BookRepository接口(interface)看:

public interface BookRepository extends JpaRepository<Book, Long> {

    @Query("SELECT b FROM Book b INNER JOIN b.categories c WHERE c IN (:categories)")
    List<Book> findByCategories(Collection<Category> categories);

如果我的查询本身有误，请修复我。当我为 findByCategories 方法运行测试时，出现错误:

testFindByCategories(com.savdev.springmvcexample.repository.JpaBookRepositoryTest): org.hibernate.QueryParameterException: Position beyond number of declared ordinal parameters. Remember that ordinal parameters are 1-based! Position: 1; nested exception is java.lang.IllegalArgumentException: org.hibernate.QueryParameterException: Position beyond number of declared ordinal parameters. Remember that ordinal parameters are 1-based! Position: 1

我必须选择哪个选项来解决它？

第二，我可以调试将参数传递到查询中的 Spring Data Jpa 逻辑吗？我收到 Spring Data Jpa 返回的代理，无法理解在何处使用断点来调试此行为。

更新:我已经使用 (?1) 修复了它:

@Query("SELECT b FROM Book b INNER JOIN b.categories c WHERE c IN (?1)")

代替

@Query("SELECT b FROM Book b INNER JOIN b.categories c WHERE c IN (:categories)")

Answer 1

由于参数名称在字节码中丢失，您需要使用 @Param注释以指示映射为 JPQL 中的 :category 变量的参数。所以，你的代码看起来像:

@Query("SELECT b FROM Book b INNER JOIN b.categories c WHERE c IN (:categories)")
List<Book> findByCategories(@Param("categories") Collection<Category> categories);

?1 当然可以，但可能不那么可读。