使用可变键定义POJO

Question

我正在尝试将 JSON 转换为 POJO，其中键是可变的。例如：以下示例中的柏林、巴黎：

{
  "Berlin": {
    "en-US": {
      "displayName": "US",
      "supportedLanguage": [
        "US"
      ],
      "FullExample": "Hello us"
    },
    "en-CA": {
      "displayName": "CA",
      "supportedLanguage": [
        "CA"
      ],
      "FullExample": "Hello CA"
    }
  },
  "Paris": {
    "en-US": {
      "displayName": "US",
      "supportedLanguage": [
        "US"
      ],
      "FullExample": "Hello US"
    },
    "en-CA": {
      "displayName": "CA",
      "supportedLanguage": [
        "CA"
      ],
      "FullExample": "Hello CA"
    }
  }
}

对于变量键（柏林、巴黎）内的所有内容，例如：

    "en-US": {
      "displayName": "US",
      "supportedLanguage": [
        "US"
      ],
      "FullExample": "Hello us"
    },
    "en-CA": {
      "displayName": "CA",
      "supportedLanguage": [
        "CA"
      ],
      "FullExample": "Hello CA"
    }

我将类定义如下：

class CityData {

Map <String, LanguageData> locale;
}

class LanguageData {
String displayName;
List<String> supportedLanguage;
String fullExample;
}

最后为了适应variableKeys，我定义了一个新对象，如下所示：

class City {

Map<String, CityData> city;

}

但是，我收到以下错误：

Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "Berlin" , not marked as ignorable (0 known properties: ])

如何将变量键存储在 POJO 中？这是必不可少的东西，所以我想通过 jackson objectmapper readValue 检索它。

Answer 1

您需要将数据解析为

Map<String, CityData>

，而不是包含 Map 属性的对象。您的根级别是地图。

Map<String, CityData> parsed = objectMapper.readValue(
  input,
  new TypeReference<Map<String, CityData>>() {});