使用Spring Boot JPA反序列化JSON类Kotlin的问题

Question

出现的错误日志：

JSON分析错误：无法构造com.lp3bmobi.paintcar_workshop_api.model.vehicletype的实例（尽管至少存在一个创建者）：没有可从Number值（3）反序列化的int/Int-argument构造函数/工厂方法

车辆类型类别

@Entity
@Table(name="vehicle_types")
@EntityListeners(AuditingEntityListener::class)
@JsonDeserialize
data class VehicleType (
        @NotBlank
        @Column(name = "type_name")
        var typeName: String ?= null
        //@JsonProperty("typeName") var typeName: String ?= null
) {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    var id: Long ?= null
    //@JsonProperty("id") var id: Long = 0

    constructor(id: Long, typeName: String?): this(typeName) {
        this.id = id
    }

   //    @JsonCreator constructor(id: Long, typeName: String?): this(typeName) {
   //        this.id = id
   //    }

}

@Entity
@Table(name="vehicles")
@EntityListeners(AuditingEntityListener::class)
data class Vehicle (
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        @Column(name = "id")
        var id: Long ?= null,

        @NotBlank
        @Column(name = "model_name")
        var modelName: String ?= null,

        @NotBlank
        @Column(name = "year")
        var year: Int ?= null,

        @NotBlank
        @Column(name = "brand_id")
        var brand: Int ?= null,

        @NotBlank
        @Column(name = "description")
        var description: String ?= null,

        @NotBlank
        @Column(name = "approved")
        var approved: Boolean ?= null,

        @OneToOne(fetch = FetchType.LAZY) //cascade = arrayOf(CascadeType.ALL)
        @JoinColumn(name = "vehicle_type_id", referencedColumnName = "id")
        var vehicleType: VehicleType,
        //@JsonProperty("vehicleType") var vehicleType: VehicleType ?= null,
)

车辆控制器

@PostMapping("/vehicle/new")
fun createVehicle(@RequestBody vehicle: Vehicle): ResponseEntity<Vehicle?>? { //EntityModel<Vehicle>
        try {
          val _vehicle: Vehicle = vehicleRepository
                  //.save(Vehicle(vehicle.content))
                 //.save(Vehicle(0, vehicle.modelName, vehicle.year, vehicle.brand,
                //              vehicle.description, false, vehicle.vehicleType))
                .save(vehicle)
           return ResponseEntity<Vehicle?>(_vehicle, HttpStatus.CREATED)
       } catch (e: java.lang.Exception) {
           return ResponseEntity<Vehicle?>(null, HttpStatus.INTERNAL_SERVER_ERROR)
    }
}

Answer 1

错误消息似乎是说Spring找不到vehicletype使用单个Int参数的构造函数，所以显而易见的是给它一个！

您可以通过添加另一个辅助构造函数来实现：

constructor(id: Int): this(null) {
    this.id = id.toLong()
}

（免责声明：我自己还没试过…… ，如果有用请告诉我们！）