gson 使用动态值的Json字符串到对象的Map

txu3uszq 于 2022-11-06 发布在其他

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我正在使用第三方jsonString，我正在尝试解析json，但有时JSON对象“RadarReports”是一个列表，有时它是一个对象。

{"RadarReports": {
    "executionTime": "135",
"RadarReport": {
        "abc": "1116591",
        "name": "abc",
        "id": "2019050311582056119",
        "ownerId": "xyz"
    },
"size" :"1"
}}

=================

{"RadarReports": {
        "executionTime": "113",
        "RadarReport": [
            {
                 "abc": "1116591",
            "name": "abc",
            "id": "2019050311582056119",
            "ownerId": "xyz"
            },
            {
            "abc": "1116591",
            "name": "abc",
            "id": "2019050311582056119",
            "ownerId": "xyz"
            },
        ]
    "size" : "2"
    }}

我尝试在下面解析，但当单个对象进入图片时失败，需要接受单个对象和对象列表。

@Data
public class Radarreports {
    private int size;
    private ArrayList<RadarreportSet> RadarReportSet;
    private ArrayList<RadarReport> RadarReport;
}

@Data
public
class ReportsResponse {
    Radarreports RadarReports;
}

URL url = new URL(queryUrl);
BufferedReader br = new BufferedReader(new InputStreamReader(url.openStream()));
Gson gson = new GsonBuilder().create();
ReportsResponse radarReports = gson.fromJson(br, ReportsResponse.class);

Gson

来源：https://stackoverflow.com/questions/74240430/json-string-to-object-mapping-with-dynamic-values

1条答案

按热度按时间

wtlkbnrh1#

您可以使用自定义的TypeAdapterFactory来解决这个问题，它会创建一个适配器，该适配器首先查看JSON数据的类型，然后在JSON对象未被 Package 在JSON数组中的位置添加特殊处理：

// Only intended for usage with @JsonAdapter
class SingleObjectOrListAdapterFactory implements TypeAdapterFactory {
    @Override
    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
        // Note: Cannot use getDelegateAdapter due to https://github.com/google/gson/issues/1028
        TypeAdapter<T> listAdapterDelegate = gson.getAdapter(type);
        TypeAdapter<JsonObject> jsonObjectAdapter = gson.getAdapter(JsonObject.class);

        return new TypeAdapter<T>() {
            @Override
            public void write(JsonWriter out, T value) throws IOException {
                listAdapterDelegate.write(out, value);
            }

            @Override
            public T read(JsonReader in) throws IOException {
                if (in.peek() == JsonToken.BEGIN_OBJECT) {
                    // Wrap JSON object in a new JSON array before parsing it
                    JsonObject jsonObject = jsonObjectAdapter.read(in);
                    JsonArray jsonArray = new JsonArray();
                    jsonArray.add(jsonObject);

                    return listAdapterDelegate.fromJsonTree(jsonArray);
                } else {
                    return listAdapterDelegate.read(in);
                }
            }
        };
    }
}

然后，可以使用@JsonAdapter为受影响的字段指定工厂：

@JsonAdapter(SingleObjectOrListAdapterFactory.class)
private ArrayList<RadarReport> RadarReport;

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gson 使用动态值的Json字符串到对象的Map

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