sql - Spring JPA : No converter data from DB in to DTO

Question

我的存储库中有一个自定义查询。我创建了一个这样的 DTO 接口(interface):

public interface ImagePathAndID {
    String getImagePath();
    Integer getIdProduct();
}

我的查询是:

@Query(value = "select image.image_path, product.product_id from    image\r\n" + 
            "           inner join product  on product.product_id = image.product_id\r\n" + 
            "           inner join category as c on product.category_id = c.category_id \r\n" + 
            "           where c.category_id = :id ", nativeQuery = true)
    public List<ImagePathAndID > selectAllImagePathForCategory(@Param("id") int id);

当我返回数据时，我得到了 getImagePath 和 getIdProduct 的空值。

List<ImagePathAndID> imagePath = this.categoryRepository.selectAllImagePathForCategory(id);


        for (ImagePathAndID image:imagePath ) {
            System.out.println(image.getImagePath() + image.getIdProduct());
        }

我得到了 ImagePathAndID 的 3 对象，但此对象的值为 null。输出是:

null,null
null,null
null,null

Answer 1

这里的关键是定义的属性要与接口(interface)方法的命名约定完全匹配。引用documentation

您应该像下面这样修改您的查询和接口(interface)方法。

查询

@Query(value ="select image.image_path as imagePath, product.product_id as productId from    image\r\n" + 
        "           inner join product  on product.product_id = image.product_id\r\n" + 
        "           inner join category as c on product.category_id = c.category_id \r\n" + 
        "           where c.category_id = :id ", nativeQuery = true)
public List<ImagePathAndID > selectAllImagePathForCategory(@Param("id") int id);

界面

public interface ImagePathAndID {
   String getImagePath();
   Integer getProductId();