Jackson Deserialize array or single object

Question

I'm using Jackson to deserialize a response from a restful call to the ups api for shipment tracking information.

In the response, if there's more than one package per shipment I get a response similar to the following snippet

    "Shipment": {
        "InquiryNumber": {
            "Code": "01",
            "Description": "ShipmentIdentificationNumber",
            "Value": "some-value-here"
        },
        "ShipperNumber": "1234",
        "Package": [{
                "TrackingNumber": "12345"
            },
            {
                "TrackingNumber": "67890"
            }
        ]
    }
  }

This is fine and I can un-marshall this using Jackson simply enough with the following:

@JsonDeserialize(builder = Shipment.Builder.class)
@Builder(builderClassName = "Builder")
@Getter
public class Shipment {

  @JsonProperty("ShipperNumber")
  private final String shipperNumber;

  @JsonProperty("Package")
  private final List<Package> packages;

  @JsonPOJOBuilder(withPrefix = "")
  public static class Builder {

  }

}

However, if there is only one package item in the api response, then rather than return it as a collection of packages with one entry, it returns it as a single object such as below:

    "Shipment": {
        "InquiryNumber": {
            "Code": "01",
            "Description": "ShipmentIdentificationNumber",
            "Value": "some-value-here"
        },
        "ShipperNumber": "1234",
        "Package": {
            "TrackingNumber": "12345"
        }
    }
  }

This throws the below error, because Jackson isn't able to deserialize the object into a list (obviously)

JSON parse error: Cannot deserialize instance of java.util.ArrayList<com.example.Package> out of START_OBJECT token;

Is there a way for Jackson to marshall the data depending on the datatype ie collection or single object?

You can use that annotation as showed in duplicate link https://stackoverflow.com/questions/56210238/how-to-parse-field-that-may-be-a-string-and-may-be-an-array-with-jackson/56210350#56210350 — Ryuzaki L, Dec 10 '19 at 17:55

Jackson Deserialize array or single object

0 Answers0