Query about flattening a nested json using Jackson

Question

I've a json

{
    "parentId": "123",
    "parentName": "abc",
    "child": {
        "childId": "456",
        "childName": "xyz",
    }  
}

My requirement is to flatten the json so that I can map it to a pojo

class MyJson{
     private String parentId;
     private String parentName;
     private String childId;

    @JsonCreator
    public MyJson(@JsonProperty("parentId"),@JsonProperty("parentName"),
                      @JsonProperty("childId")){
        this.parentId = parentId;
        this.parentName = parentName;
        this.childId = childId;
    }
}

I know I can always create another pojo for Child Object, but I was wondering is there a way to directly map the nested child attribute to the pojo?

Answer 1

child is a JSON Object and you need to declare it as a Map:

class MyJson {
    private String parentId;
    private String parentName;
    private String childId;

    @JsonCreator
    public MyJson(@JsonProperty("parentId") String parentId,
                  @JsonProperty("parentName") String parentName,
                  @JsonProperty("child") Map<String, String> child) {
        this.parentId = parentId;
        this.parentName = parentName;
        this.childId = child.get("childId");
    }
}