JSON Jackson将不同的密钥解析到同一个字段中 [英] JSON Jackson parse different keys into same field

问题描述

我有一个POJO，其中包含一个字段：

I have a POJO which has a field:

public class Media {
 private Asset asset;
}

将json响应解析为此资产POJO时，一切正常。但是这个资产带来的关键略有不同。它可以是：

Everything works perfectly when parsing a json response into this asset POJO. but however there is a slight difference with the key this asset comes with. It can either be:

  @JsonProperty("cover_asset")

或

  @JsonProperty("asset")

有没有办法注释POJO以识别这种情况并反序列化到同一个字段中。它们不可能出现在同一个响应中。

Is there a way to annotate the POJO to recognize this case and de-serialize into the same field. Its not possible for both of them to appear in the same response.

推荐答案

更简洁，我建议使用两个独立的@JsonSetter对此的注释。这是一个有效的例子。这意味着你的java类只有一个getter方法用于属性而不是两个。您也可以将不希望暴露给Media私人客户端的setter设置为以特殊方式处理其中一个json密钥。

More succinctly, I would suggest using two separate @JsonSetter annotations for this. Here's a working example. This means that your java class will only have one getter method to use for the property instead of two. You can also make the setter you don't want exposed to clients of Media private and treat one of the json keys in a special manner.

import com.fasterxml.jackson.annotation.JsonGetter;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSetter;
import com.fasterxml.jackson.databind.ObjectMapper;

@SuppressWarnings("unused")
public class Media {

    private Asset asset;

    @JsonGetter("asset")
    public Asset getAsset() {
        return asset;
    }

    @JsonSetter("asset")
    public void setAsset(Asset asset) {
        this.asset = asset;
    }

    @JsonSetter("cover_asset")
    private void setMediaAsset(Asset asset) {
        if (this.asset == null) {
            setAsset(asset);
        }
    }


    private static class Asset {
        @JsonProperty("foo")
        private String foo;
    }

    public static void main(String[] args) throws Exception {
        String withAsset = "{'asset': {'foo':'bar'}}";
        String withCoverAsset = "{'cover_asset': {'foo':'bar'}}";

        ObjectMapper mapper = new ObjectMapper();
        Media mediaFromAsset = mapper.readValue(withAsset.replace('\'','"'), Media.class);
        Media mediaFromCoverAsset = mapper.readValue(withCoverAsset.replace('\'','"'), Media.class);

        System.out.println(mediaFromAsset.asset.foo.equals(mediaFromCoverAsset.asset.foo));

    }
}

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