public static <K, V> Map<K, V> getMap(
      JsonNode jsonNode, String fieldName, TypeReference<Map<K, V>> mapType) {
    Preconditions.checkNotNull(jsonNode, "JsonNode should not be null");

    JsonNode mapNode = jsonNode.get(fieldName);
    if (mapNode == null) {
      return new HashMap<>();
    }

    return OBJECT_MAPPER.convertValue(mapNode, mapType);
  }
Retrieve the given map from a JsonNode, and return empty map if the field doesn't exist.
amoro-common/src/main/java/org/apache/amoro/utils/JacksonUtil.java