使用@JsonCreator 在一个 JSON DTO 中创建相同 class 的两个实例

Question

I would like to deserialize JSON of this structure:

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

I have such POJO to create price setting from a HTTP request:

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;
  }

}

this is 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;

}

I would like to create these two instances of ObjectPricingSetting with @JsonCreator .

Q: How should I anotate @JsonProperty parameter in ObjectPricingSetting constructor to recognize what JSON value should use to create these two instances?

Answer 1

You can use @JsonUnwrapped with a prefix in your parent class:

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

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

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

}

Then you can use the normal @JsonCreator/@JsonProperty in your nested DTO, without the prefix:

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