最简单的技巧是您可以在类中添加具有相同序列化名称但具有字符串数据类型的额外字段。像这样-
data class PersonDto(
@SerializedName("firstName") val first: String,
@SerializedName("lastName") val last: String,
@SerializedName("favorites") val favorites: FavoriteDto,
@SerializedName("favorites") val favoritesStr: String,
)
由于 Gson 中没有任何内容作为“必需”字段，因此如果 JSON 中缺少某些内容，您只会在反序列化对象中获得 null。因此，如果有一个空字符串，FavoriteDto 对象将为空，否则不为空。
编辑
我正在添加一些我之前编写的 Java 代码。这可能会有所帮助：
public class PersonDto {
private FavoriteDto favorites;
private String favoritesStr;
public FavoriteDto getResponseDataObject() {
return favorites;
}
public void setResponseDataObject(FavoriteDto favorites) {
this.favorites = favorites;
}
public String getResponseDataString() {
return favoritesStr;
}
public void setResponseDataString(String favoritesStr) {
this.favoritesStr = favoritesStr;
}
定义反序列化器：
public static class ArrayObjectDualityDeserializer implements JsonDeserializer<PersonDto> {
public PersonDto deserialize(JsonElement json, Type typeOfT,
JsonDeserializationContext context) throws JsonParseException {
PersonDto response = new PersonDto();
JsonObject object = json.getAsJsonObject();
if(object.get("favorites").isJsonArray()) {
} else if(object.get("favorites").isJsonObject()) {
try {
FavoriteDto dtoObject = gson.fromJson(object.get("favorites"), FavoriteDto.class);
response.setResponseDataObject(dtoObject);
} catch (JsonSyntaxException e) {
DebugLogger.e("Error " + e);
}
} else if (object.get("favorites").isJsonNull()) {
} else {
response.setResponseDataString(object.get("favorites").getAsString());
}
}
}
还有：
public static Gson gson = new GsonBuilder()
.registerTypeAdapter(PersonDto.class, new ArrayObjectDualityDeserializer())
.create();
最后：
private static Retrofit retrofit = null;
private static OkHttpClient.Builder httpClient = null;
private static OkHttpClient session_client = null;
httpClient = new OkHttpClient.Builder();
httpClient.addInterceptor(new SessionOkHttpInterceptor());
session_client = httpClient.build();
retrofit = new Retrofit.Builder()
.baseUrl(BASE_URL)
.client(session_client)
.addConverterFactory(GsonConverterFactory.create(gson))
.build();