spring - Spring数据存储库不会以多对多关系保存数据

Question

我正在创建一个数据模型，使我可以管理发票。我遇到的问题是当我尝试通过@POST使用服务时。一切都正确，即使我在数据库中进行验证并且没有外键invoice_id的记录
错误在这里:

@Entity
@Table(name = "invoice")
data class Invoice (

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        val id: Int? = 0,

        val createdAt: LocalDateTime? = LocalDateTime.now(),
        val updatedAt: LocalDateTime? = LocalDateTime.now(),

        val nombre: String? = "",
        val direccion: String? = "",
        val telefono: String? = "",

        var order_total : Int? = null,

        @OneToMany(mappedBy = "invoice", cascade = [CascadeType.ALL])
        @JsonManagedReference
        val invoiceItems: List<InvoiceItem>? = mutableListOf()

)

@Entity
@Table(name = "item")
data class Item(
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        val id: Long? = null,
        val name: String? = null,
        val description: String? = null,
        val price: Int? = null,
        val img_url: String? = null,
        val createdAt: LocalDateTime? = LocalDateTime.now(),
        val updatedAt: LocalDateTime? = LocalDateTime.now(),

        @OneToMany(mappedBy = "item", cascade = [CascadeType.ALL])
        @JsonBackReference
        val items: List<InvoiceItem>? = mutableListOf()

        )

@Entity
@Table(name = "invoice_item")
data class InvoiceItem(

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        val id: Int? = 0,

        val quantitiy: Int? = 0,

        @ManyToOne
        @JoinColumn (name = "invoice_id")
        @JsonIgnore
        val invoice: Invoice? = null,

        @ManyToOne
        @JoinColumn
        val item: Item? = null

)

HTTP/1.1 200 
Content-Type: application/json
Transfer-Encoding: chunked
Date: Sat, 08 Aug 2020 04:35:13 GMT
Keep-Alive: timeout=60
Connection: keep-alive

{
  "id": 5,
  "createdAt": "2020-08-07T23:35:13.2283331",
  "updatedAt": "2020-08-07T23:35:13.2283331",
  "nombre": "Z",
  "direccion": "Bosquera",
  "telefono": "12000",
  "order_total": 1000,
  "invoiceItems": [
    {
      "id": 7,
      "quantitiy": 10,
      "item": {
        "id": 1,
        "name": "Costilla de Cerdo Ahumadas Ranchera",
        "description": "Costilla Ahumada, 500 Gramo(s).",
        "price": 30700,
        "img_url": "https://images.rappi.com/products/443434-1594427331970.png",
        "createdAt": "2020-08-07T23:28:03",
        "updatedAt": "2020-08-07T23:28:03"
      }
    },
    {
      "id": 8,
      "quantitiy": 10,
      "item": {
        "id": 2,
        "name": "Hamburguesa Preasada Zenu X 400G",
        "description": "Hamburguesa Preasada Zenu X 400G. 25% Reducido En Sodio, Buena Fuente De Proteína PLU: 802599",
        "price": 12350,
        "img_url": "https://images.rappi.com/products/802599-1594427485528.png",
        "createdAt": "2020-08-07T23:28:03",
        "updatedAt": "2020-08-07T23:28:03"
      }
    }
  ]
}

非常感谢您的帮助，我敢于发表，因为我已经尝试了解问题所在，但我找不到它

Answer 1

对于双向关系，需要同步两端，这意味着必须设置每个InvoiceItem的发票字段，然后才能设置外键。

fun addOrder(invoice: Invoice): ResponseEntity<Invoice> {
   invoice.invoiceItems.forEach { it -> it.invoice= invoice}
   ResponseEntity.ok(parentRepository.save(invoice))
}