Jackson objectMapper 将不同的 json 属性映射到同一个 pojo

Question

I have a very simple json which I am trying to map to an object.

JSON :

[
    {
        "cust_lpid": "0119b9f7f99ad2161de7b0b",
        "cust_uid": "soumavtestflow"
    }
]

My Mapper Class:

@JsonIgnoreProperties(ignoreUnknown = true)
public class CustomerSegmentRequest {

    @JsonProperty("LPID")
    String cust_lpid;
    @JsonProperty("UserId")
    String cust_uid;

    public String getCust_lpid() {
        return cust_lpid;
    }
    public void setCust_lpid(String cust_lpid) {
        this.cust_lpid = cust_lpid;
    }
    public String getCust_uid() {
        return cust_uid;
    }
    public void setCust_uid(String cust_uid) {
        this.cust_uid = cust_uid;
    }
}

When I do a

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
LPIDCustIDMapper[] custSegResp = objectMapper.readValue(responseBody,CustomerSegmentRequest [].class);

I don't get any values populated in custSegResp.

However when i remove the @JsonProperty it works. I need the json property name to map an incoming request and hence don't wanna create a separate mapping class. Is there a way to achieve the same?

Answer 1

use @JsonAlias

@JsonIgnoreProperties(ignoreUnknown = true)
public class CustomerSegmentRequest {

   @JsonAlias({"cust_lpid", "LPID" })
   String cust_lpid;

   @JsonAlias({"cust_uid", "UserId" })
   String cust_uid;

   public String getCust_lpid() {
      return cust_lpid;
   }

   public void setCust_lpid(String cust_lpid) {
      this.cust_lpid = cust_lpid;
   }

    public String getCust_uid() {
      return cust_uid;
   }

    public void setCust_uid(String cust_uid) {
       this.cust_uid = cust_uid;
   }
}

Answer 2

@JsonProperty("keyName") is to specify what is the key is the JSON which maps to this field.

The reason it works without it is, without it Jackson tries to first match via getters/setters after removing the get / set prefix keys and normalizing the case ( getAbCd -> abCd ), which in your case gives the keys as in the JSON.

You need to modify your @JsonProperty("LPID") to @JsonProperty("cust_lpid") or if you need to map to multiple keys use @JsonAlias({"cust_lpid", "LPID" })