使用 JpaSpecificationExecutor 时使用 QueryHint

本文介绍了使用 JpaSpecificationExecutor 时使用 QueryHint的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着跟版网的小编来一起学习吧！

问题描述

我使用 spring 数据和 JpaSpecificationExecutor::findAll 方法来获取我的模型.调用此方法时如何使用查询提示?
上面的源代码工作正常，但我无法为我的 JPA 提供程序(在我的情况下为 EclipseLink)设置 QueryHint.

@Repository公共接口 ProductRepository 扩展了 JpaRepository<Product, Integer>, JpaSpecificationExecutor<Product>{}@服务公共类产品服务{@自动连线私有产品存储库产品存储库；公开列表<产品>findByTitle(字符串语言环境，字符串 titleToSearch){return productRepository.findAll((Root root, CriteriaQuery {return builder.equal(builder.function("jsonb_extract_path_text", String.class, root.<String>get("title"), builder.literal(locale)), titleToSearch);});}}

我使用spring-data使用Query Hints的方式如上，

@Repository公共接口 ProductRepository 扩展了 JpaRepository<Product, Integer>, JpaSpecificationExecutor<Product>{@QueryHints(值 = {@QueryHint(name = org.eclipse.persistence.config.QueryHints.BATCH_TYPE, value = "JOIN"),@QueryHint(名称 = org.eclipse.persistence.config.QueryHints.BATCH，值 = p.productCategory")，@QueryHint(名称 = org.eclipse.persistence.config.QueryHints.BATCH，值 = p.productFileList")}, forCounting = false)@Query("从产品 p 中选择 p")公开列表<产品>寻找();}

我还发现 this 尚未解决.

解决方案

当我想使用 spring-data 创建查询时，我遵循上述算法.

<块引用>

1) CrudRepository、PagingAndSortingRepository、JpaRepository等spring-data现有接口是否已经提供查询代码> 等等?
示例:saveAndFlush 或 findAll 方法，更多内容请参见文档.

产品 product = new Product();//二传手..productRepository.saveAndFlush();

<块引用>

2) 我可以在方法名称中使用关键字创建方法吗?
示例:计数，更多内容请参见文档.

@Repository公共接口 ProductRepository 扩展了 JpaRepository<Product, Integer>{Long countByTitle(String title);列表<产品>findByTitleLikeAndVisible(字符串标题，布尔可见)；}

<块引用>

3) 我可以创建自定义查询方法编写 JPQL 吗?
示例:文档.
在这种情况下，spring data 不会尝试使用方法名称中的关键字来创建查询，因此方法名称可以是任何你想要的.

@Repository公共接口 ProductRepository 扩展了 JpaRepository<Product, Integer>{@Query("SELECT COUNT(p) FROM Product p WHERE p.title=?1")Long countByTitle(String title);@Query("SELECT p FROM Product p WHERE p.title LIKE :title AND visible=true")列表<产品>findByTitleLikeAndVisibleTrue(@Param("title") 字符串标题);}

<块引用>

4) 我想要变量列名还是变量where 条件?那么解决方案就是规范.
示例:docs，所以回答p>

@Repository公共接口 ProductRepository 扩展了 JpaRepository<Product, Integer>, JpaSpecificationExecutor<Product>{}@服务公共类产品服务{@自动连线私有产品存储库产品存储库；公开列表<产品>findByColumn(String columnName, Object value) {return productRepository.find((Root<Product> root, CriteriaQuery<?> 查询, CriteriaBuilder builder) -> {return builder.and(builder.equal(root.<String>get(columnName), value));});}}

<块引用>

5) 我想要更多吗? 解决方案是获取 EntityManager 并像我在没有 spring 数据库的情况下使用它一样使用它.(这是这个问题的答案)
示例:所以回答，更多在文档

//创建一个接口并添加您希望与 EntityManger 一起使用的方法.公共接口 ProductRepositoryExt {公开列表<产品>findByTitle(字符串标题);}//实现你创建的接口.请注意，类名必须与附加了Impl"的 spring-data @Repository 接口相同.公共类 ProductRepositoryImpl 实现 ProductRepositoryExt {@PersistenceContext私人 EntityManager em;@覆盖公开列表<产品>findByTitle(字符串标题){//em.getTransaction().begin();String sql = "SELECT p FROM Product p WHERE p.title=:title')";TypedQuery<ProductCategory>查询 = em.createQuery(sql, Product.class);query.setParameter("title", title);//添加你想要的查询提示..query.setHint(org.eclipse.persistence.config.QueryHints.BATCH_TYPE, "JOIN");query.setHint(org.eclipse.persistence.config.QueryHints.BATCH, "p.productCategory");返回查询.getResultList();//em.getTransaction().commit();}}//从你的 spring-data @Repository 接口扩展这个接口.@Repository公共接口 ProductRepository 扩展 JpaRepository, ProductCategoryRepositoryExt {}

I use spring data and the JpaSpecificationExecutor::findAll method to fetch my models. How I could use query hints when calling this method?
The above source code works fine but I can't set QueryHint for my JPA provider (in my case EclipseLink).

@Repository
public interface ProductRepository extends JpaRepository<Product, Integer>, JpaSpecificationExecutor<Product> {
}

@Service
public class ProductService {

    @Autowired
    private ProductRepository productRepository;

    public List<Product> findByTitle(String locale, String titleToSearch) {
        return productRepository.findAll((Root<ProductCategory> root, CriteriaQuery<?> query, CriteriaBuilder builder) -> {
            return builder.equal(builder.function("jsonb_extract_path_text", String.class, root.<String>get("title"), builder.literal(locale)), titleToSearch);
        });
    }
}

The way I use the Query Hints using spring-data is the above,

@Repository
public interface ProductRepository extends JpaRepository<Product, Integer>, JpaSpecificationExecutor<Product> {

    @QueryHints(value = {
        @QueryHint(name = org.eclipse.persistence.config.QueryHints.BATCH_TYPE, value = "JOIN"),
        @QueryHint(name = org.eclipse.persistence.config.QueryHints.BATCH, value = "p.productCategory"),
        @QueryHint(name = org.eclipse.persistence.config.QueryHints.BATCH, value = "p.productFileList")
    }, forCounting = false)
    @Query("SELECT p FROM Product p")
    public List<Product> find();
}

I 've also found this which is unresolved yet.

解决方案

When I want to create a query using spring-data I follow the above algorithm.

1) Is the query already provided by the existing interfaces of spring-data like CrudRepository, PagingAndSortingRepository, JpaRepository etc?
Examples: saveAndFlush or findAll methods, more in docs.

Product product = new Product();
// Setters..
productRepository.saveAndFlush();

2) Can I create a method using keywords inside method names?
Examples: count, more in docs.

@Repository
public interface ProductRepository extends JpaRepository<Product, Integer> {

    Long countByTitle(String title);

    List<Product> findByTitleLikeAndVisible(String title, boolean visible);
}

3) Can I create a custom query method writing JPQL?
Examples: docs.
In this case spring data does not try to create the query using keywords inside method names, so the method names can be whatever you wish.

@Repository
public interface ProductRepository extends JpaRepository<Product, Integer> {

    @Query("SELECT COUNT(p) FROM Product p WHERE p.title=?1")
    Long countByTitle(String title);

    @Query("SELECT p FROM Product p WHERE p.title LIKE :title AND visible=true")
    List<Product> findByTitleLikeAndVisibleTrue(@Param("title") String title);
}

4) Do I want variable column names or variable where conditions? Then the solution is the Specification.
Example: docs, so answer

@Repository
public interface ProductRepository extends JpaRepository<Product, Integer>, JpaSpecificationExecutor<Product> {
}


@Service
public class ProductService {

    @Autowired
    private ProductRepository productRepository;

    public List<Product> findByColumn(String columnName, Object value) {
        return productRepository.find((Root<Product> root, CriteriaQuery<?> query, CriteriaBuilder builder) -> {
            return builder.and(builder.equal(root.<String>get(columnName), value));
        });
    }
}

5) Do I want more? The solution is to get the EntityManager and use it like I used it without the spring data library. (This is the answer to this so question)
Example: so answer, more in docs

// Create an interface and add the methods you wish to use with EntityManger.
public interface ProductRepositoryExt {
    public List<Product> findByTitle(String title);
}

// Implement the interface you created. Be careful the class name must be identical to the spring-data @Repository interface with the "Impl" appended.
public class ProductRepositoryImpl implements ProductRepositoryExt {

    @PersistenceContext
    private EntityManager em;

    @Override
    public List<Product> findByTitle(String title) {
//        em.getTransaction().begin();
        String sql = "SELECT p FROM Product p WHERE p.title=:title')";
        TypedQuery<ProductCategory> query = em.createQuery(sql, Product.class);
        query.setParameter("title", title);
        //  Add the query hints you wish..
        query.setHint(org.eclipse.persistence.config.QueryHints.BATCH_TYPE, "JOIN");
        query.setHint(org.eclipse.persistence.config.QueryHints.BATCH, "p.productCategory");

        return query.getResultList();
//        em.getTransaction().commit();
    }
}

// Extend this interface from your spring-data @Repository interface.
@Repository
public interface ProductRepository extends JpaRepository<Product, Integer>, ProductCategoryRepositoryExt {
}

这篇关于使用 JpaSpecificationExecutor 时使用 QueryHint的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！

本站部分内容来源互联网,如果有图片或者内容侵犯了您的权益，请联系我们，我们会在确认后第一时间进行删除！

使用 JpaSpecificationExecutor 时使用 QueryHint

问题描述

相关文档推荐