我能够通过帮助LocalDateTime类型适配器自己解决这个问题：

@Bean
    public Gson gson() {
        return new GsonBuilder()
                .registerTypeAdapter(LocalDateTime.class, new JsonDeserializer<LocalDateTime>() {
                    @Override
                    public LocalDateTime deserialize(JsonElement json, Type type, JsonDeserializationContext jsonDeserializationContext) throws JsonParseException {
                        JsonObject jo = json.getAsJsonObject();
                        return LocalDateTime.of(jo.get("year").getAsInt(),
                                jo.get("monthValue").getAsInt(),
                                jo.get("dayOfMonth").getAsInt(),
                                jo.get("hour").getAsInt(),
                                jo.get("minute").getAsInt(),
                                jo.get("second").getAsInt(),
                                jo.get("nano").getAsInt());
                    }
                }).create();

如果您遇到了同样的问题，但您还需要字符串格式的日期（例如2019-11-18），您可以使用try catch块，如下所示：

private static final Gson gson = new GsonBuilder().registerTypeAdapter(LocalDate.class, new JsonDeserializer<LocalDate>() {
    @Override
    public LocalDate deserialize(JsonElement json, Type type, JsonDeserializationContext jsonDeserializationContext) throws JsonParseException {
        try {
            return LocalDate.parse(json.getAsJsonPrimitive().getAsString());
        } catch (IllegalStateException e) {
            JsonObject jo = json.getAsJsonObject();
            return LocalDate.of(jo.get("year").getAsInt(), jo.get("monthValue").getAsInt(), jo.get("dayOfMonth").getAsInt());
        }
    }
}).create();