尝试获取应用程序中存储的所有“折扣”对象时遇到问题。 “折扣”是由以下类表示的对象
@Entity
@NoArgsConstructor
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "store")
public class Discount {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
// some fields like a description or a percentage providing info about a discount
@ManyToOne
@JoinColumn(name = "id_store")
private Store store;
@ManyToOne
@JoinColumn(name = "id_brand")
@JsonManagedReference
private Brand brand;
// getters, setters, equals and hashcode overriden below
如您所见，Discount对象可以属于商店或品牌。我确保使用触发器在代码和数据库中都只设置一个字段。在我的应用程序中，折扣既可以由品牌提供（因此我不必为此品牌的每个商店都创建折扣），也可以由特定商店提供自己的折扣。我的班级商店看起来像这样
@Entity
@NoArgsConstructor
public class Store extends Entite {
@OneToMany(mappedBy = "store", cascade = CascadeType.ALL)
private Set<Discount> discounts;
@ManyToOne
@JoinColumn(name = "id_brand", nullable = false)
private Brand brand;
// getters, setters, equals and hashcode overriden below
如您所见，商店有一组折扣，并且属于一个品牌。它扩展了Entite类，因为在我的应用中我也有Sport Clubs，并且它们共享一些信息，但这与我的问题无关。 最后，这是品牌类
@Entity
@NoArgsConstructor
public class Brand {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@OneToMany(mappedBy = "brand", cascade = CascadeType.ALL)
private Set<Store> stores;
@OneToMany(mappedBy = "brand", cascade = CascadeType.ALL)
@JsonBackReference
private Set<Discount> discounts;
// getters, setters, equals and hashcode overriden below
“我的品牌”类别具有一组商店和一组折扣。
我的问题是我无法通过扩展interface DiscountRepository的{{1}}来通过简单的FindAll获取所有折扣，因为某些折扣是在关联中检索的。我从FindAll方法获得的答案如下
JpaRepository<Discount, Long>这里的问题是有一个Store的Discount Fetch，因此，该Discount不在方法返回的原始列表中，而是在与Discount相关的Store对象中。我试图将[
{
// discount fields such as percentage, ruling, etc
"store": {
"id": 75,
"name": "Nike Store",
"discounts": [
75
],
"brand": {
"name": "Nike",
"store": [
75
]
}
},
"brand": null
},
{
// discount fields such as percentage, ruling, etc
"store": null,
"brand": {
"name": "Uniqlo",
"stores": [
90
]
}
},
{
// discount fields such as percentage, ruling, etc
"store": null,
"brand": {
"name": "FNAC",
"stores": [
{
"id": 76,
// some store fields
// problem here because Discount are retrieved here and therefore not displayed in the list, only here
"discounts": [
{
// discount fields such as percentage, ruling, etc
// for an offer that isn't present in the original list returned
// by the find all method but only here, associated to this Store object
"store": 76,
"brand": null
}
],
"brand": {
"name": "FNAC",
"stores": [
76
]
}
}
]
}
},
76
]
添加到我的“商店和折扣”关联中，但这不能解决问题。因此，有没有办法获取“仅一个级别的关联”？我的意思是，我只想检索我的Discount对象，而只检索Brand和Store信息，而不检索Store或Brand及其所有关联（如Set of Discount）。我希望我很清楚，不要犹豫，问我任何问题。