将orderBy排序添加到搜索规范中

Question

我想通过添加order by params来扩展这个规范。

public class ProductSearchParams {
    private String title;
    private String type;
    private LocalDateTime publishedAt;
    private String sort;
    private List<String> sortBy;
}

public Page<ProductFullDTO> findProducts(ProductSearchParams params, Pageable pageable) {
        Specification<Product> spec = (root, query, cb) -> {
            List<Predicate> predicates = new ArrayList<>();
            if (params.getTitle() != null) {
                predicates.add(cb.equal(root.get("title"), params.getTitle()));
            }
            if (params.getType() != null) {
                predicates.add(cb.equal(root.get("type"), params.getType()));
            }
            if (params.getPublishedAt() != null) {
                predicates.add(cb.greaterThan(root.get("publishedAt"), params.getPublishedAt()));
            }
            return cb.and(predicates.toArray(new Predicate[predicates.size()]));
        };
        return productService.findAll(spec, pageable).map(productMapper::toFullDTO);
    }

public Page<ProductFullDTO> findProducts(ProductSearchParams params, Pageable pageable) {
        Specification<Product> spec = (root, query, cb) -> {
            List<Predicate> predicates = new ArrayList<>();
            if (params.getTitle() != null) {
                predicates.add(cb.equal(root.get("title"), params.getTitle()));
            }
            if (params.getType() != null) {
                predicates.add(cb.equal(root.get("type"), params.getType()));
            }
            if (params.getPublishedAt() != null) {
                predicates.add(cb.greaterThan(root.get("publishedAt"), params.getPublishedAt()));
            }
            if (params.getPublishedAt() != null) {
                predicates.add(cb.greaterThan(root.get("publishedAt"), params.getPublishedAt()));
            }
            query.orderBy(builder.desc((root.join(Prodotto_.listaQuoteIng))
                    .get(QuotaIngrediente_.perc_ing)));

            return cb.and(predicates.toArray(new Predicate[predicates.size()]));
        };
        return productService.findAll(spec, pageable).map(productMapper::toFullDTO);
    }

我找不到解决办法如何实施这一点。你能给我一些建议吗？

Answer 1

您是否在询问如何使用sortby列表来指定排序顺序？以下措施应起作用：

query.orderBy(sortyBy.stream()
    .map(root::get)
    .map(cb::desc)
    .toList());

您还可以通过sort查询参数（例如sort=name,asc&sort=type,desc&sort=listaquoteing.perc_ing,desc)将排序顺序传递给pageable，并轻松地将其调整为Criteria API，请参见下面的答案。