JPA查询之Specification以及HQL、SQL查询
1、Specification
- //查询条件List
- List<Predicate> predicateList = new ArrayList<Predicate>();
-
- Specification specification = new Specification() {
- @Override
- public Predicate toPredicate(Root root, CriteriaQuery criteriaQuery, CriteriaBuilder criteriaBuilder) {
- //root即是Join<>内部第一个泛型的类型,意思就是用SkuProduct与Picture通过SkuProduct的pictures左联
- Join<SkuProduct,Picture> skuProductPictureJoin = root.join("pictures",JoinType.INNER);
- //添加第1个查询条件:SkuProduct的code等于skuProduct.getCode(),然后将这个criteriaBuilder的条件添加到predicateList
- predicateList.add(criteriaBuilder.equal(root.get("code"),skuProduct.getCode()));
- //添加第2个条件
- predicateList.add(criteriaBuilder.notEqual(skuProductPictureJoin.get("pictureType"),0));
- //返回
- return criteriaBuilder.and(predicateList.toArray(new Predicate[predicateList.size()]));
- }
- };
-
- //重要说明:Specification不支持右连接!
- //Specification specification = new Specification() {
- // @Override
- // public Predicate toPredicate(Root root, CriteriaQuery criteriaQuery, CriteriaBuilder criteriaBuilder) {
- // Join<Picture,SkuProduct> skuProductPictureJoin = root.join("pictures",JoinType.RIGHT);
- // predicateList.add(criteriaBuilder.notEqual(root.get("pictureType"),0));
- // predicateList.add(criteriaBuilder.equal(skuProductPictureJoin.get("code"),skuProduct.getCode()));
- // return criteriaBuilder.and(predicateList.toArray(new Predicate[predicateList.size()]));
- // }
- //};
-
- List<SkuProduct> results = skuProductRepository.findAll(specification);
- if(results!=null){
- results.stream().forEach(result->{
- System.out.println(result);
- });
- }
2、HQL
- @Query(value = "SELECT p FROM Picture p WHERE p.code= :code")
- List<Picture> findByPicture(@Param(value = "code") String code);
3、SQL
3.1--:占位符
- @Query(value = "SELECT p.* FROM picture p LEFT JOIN sku_product_pictures sp_p ON p.id=sp_p.pictures_id LEFT JOIN sku_product sp ON sp_p.sku_product_id=sp.id WHERE sp.code= :code AND p.picture_type=0",nativeQuery = true)
- List<Picture> findBySkuProductCodeAndPicture(@Param(value = "code") String code);
3.2--?占位符
- @Query(value = "SELECT p.* FROM picture p LEFT JOIN sku_product_pictures sp_p ON p.id=sp_p.pictures_id LEFT JOIN sku_product sp ON sp_p.sku_product_id=sp.id WHERE sp.code=?1 AND p.picture_type=?2",nativeQuery = true)
- List<Picture> findSkuProductCodeAndPicture(String code,int pictureType);
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