使用@JsonCreator 在一個 JSON DTO 中創建相同 class 的兩個實例

Question

我想反序列化這個結構的 JSON ：

{
"employee_pricing_type":"COMPUTE_BY_OWN_RATE",
"employee_rate":10,    
"customer_pricing_type":"COMPUTE_BY_OWN_RATE",
"customer_rate":200    
}

我有這樣的 POJO 從 HTTP 請求創建價格設置：

public class ObjectPricingSetting {

  @JsonProperty("pricing_type") // describes output 
  private final ObjectPricingType pricingType;

  @JsonProperty("own_rate") // describes output 
  private final BigDecimal ownRate;

  public ObjectPricingSetting(final ObjectPricingType pricingType, final BigDecimal ownRate) {

    AssertUtils.notNull(pricingType, "pricingType");
    this.pricingType = pricingType;

    if (ownRate != null) {
      AssertUtils.isGtZero(ownRate, "ownRate");
      this.ownRate = ownRate;
    } else {
      this.ownRate = null;
    }

  }

  public ObjectPricingType getPricingType() {
    return pricingType;
  }

  public BigDecimal getOwnRate() {
    return ownRate;
  }

}

這是 DTO：

@JsonInclude(JsonInclude.Include.NON_NULL)
public class ObjectPricingCommand extends BaseDto<ObjectId> {

  @JsonProperty(value = "employee_pricing_setting")
  private ObjectPricingSetting employeePricingSetting;

  @JsonProperty(value = "customer_pricing_setting")
  private ObjectPricingSetting customerPricingSetting;

}

我想用@JsonCreator創建這兩個ObjectPricingSetting實例。

問：我應該如何在ObjectPricingSetting構造函數中注釋@JsonProperty參數以識別應該使用什么 JSON 值來創建這兩個實例？

Answer 1

您可以在父 class 中使用帶有前綴的 @JsonUnwrapped：

@JsonInclude(JsonInclude.Include.NON_NULL)
public class ObjectPricingCommand extends BaseDto<ObjectId> {

  @JsonUnwrapped(prefix = "employee_")
  private ObjectPricingSetting employeePricingSetting;

  @JsonUnwrapped(prefix = "customer_")
  private ObjectPricingSetting customerPricingSetting;

}

然后你可以在你的嵌套 DTO 中使用普通的 @JsonCreator/@JsonProperty，沒有前綴：

public class ObjectPricingSetting {
  @JsonCreator
  public ObjectPricingSetting(
     @JsonProperty("pricing_type") final ObjectPricingType pricingType, 
     @JsonProperty("rate") final BigDecimal ownRate) {
  ...