如何使用Jackson注释将嵌套值映射到属性？

问题描述

假设我正在调用API，该API会响应产品的以下JSON：

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"
  }
}

我能够映射产品ID和名称使用杰克逊注释就好了：

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;
    }
}

然后使用fromJson方法创建产品：

And then using the fromJson method to create the product:

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

但现在我正在试图弄清楚如何获取品牌名称，这是一个嵌套的属性。我希望这样的东西能起作用：

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;
    }

但当然没有。有没有一种简单的方法可以使用注释来实现我想要的东西？

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

推荐答案

你可以实现这一点：

String brandName;

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

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