java - How to map a nested value to a property using Jackson annotations?

Question

Let's say I'm making a call to an API that responds with the following JSON for a product:

{
  "id": 123,
  "name": "The Best Product",
  "brand": {
     "id": 234,
     "name": "ACME Products"
  }
}

I'm able to map the product id and name just fine using Jackson annotations:

public class ProductTest {
    private int productId;
    private String productName, brandName;

    @JsonProperty("id")
    public int getProductId() {
        return productId;
    }

    public void setProductId(int productId) {
        this.productId = productId;
    }

    @JsonProperty("name")
    public String getProductName() {
        return productName;
    }

    public void setProductName(String productName) {
        this.productName = productName;
    }

    public String getBrandName() {
        return brandName;
    }

    public void setBrandName(String brandName) {
        this.brandName = brandName;
    }
}

And then using the fromJson method to create the product:

  JsonNode apiResponse = api.getResponse();
  Product product = Json.fromJson(apiResponse, Product.class);

But now I'm trying to figure out how to grab the brand name, which is a nested property. I was hoping that something like this would work:

    @JsonProperty("brand.name")
    public String getBrandName() {
        return brandName;
    }

But of course it didn't. Is there an easy way to accomplish what I want using annotations?

The actual JSON response I'm trying to parse is very complex, and I don't want to have to create an entire new class for every sub-node, even though I only need a single field.

Answer 1

You can achieve this like that:

String brandName;

@JsonProperty("brand")
private void unpackNameFromNestedObject(Map<String, String> brand) {
    brandName = brand.get("name");
}