在前端使用 fetch 进行请求时后端的 LocalDateTime 序列化正常

前端请求代码

fetch(`${ctx}/direct/game/getCurrentGame`)
        .then(res => res.json())
        .then(json => console.log(json));

// 返回数据
{
    "code": 200,
    "message": null,
    "data": {
        "id": 1032486183939768321,
        "startTime": "2018-08-23T13:04:23",
        "endTime": "2018-08-23T13:40:54",
    }
}

后端 Java 测试代码

final ResultActions resultActions = restMockMvc.perform(get("/direct/game/getCurrentGame"));
final Game currentGame = action2Entity(resultActions, new TypeReference<JsonResult<Game>>() {
});
log.info("currentGame: {}", currentGame);

// action2Entity 方法大致上是这个样子
protected <T extends Serializable> T action2Entity(ResultActions resultActions, TypeReference<JsonResult<T>> type) throws IOException {
    final JsonResult<T> jsonResult = om.readValue(resultActions.andReturn().getResponse().getContentAsString(), type);
    return jsonResult.getData();
}

但会抛出异常

com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.time.LocalDateTime out of START_ARRAY token
 at [Source: {"code":200,"message":null,"data":{"id":1032486183939768321,"startTime":[2018,8,23,13,4,23],"endTime":[2018,8,23,13,40,54]}}; line: 1, column: 103] (through reference chain: com.rx.f3d.common.web.JsonResult["data"]->com.rx.f3d.module.entity.game.Game["startTime"])

所以为什么使用 SpringTest 测试与前端不一致？而且又应该怎样才能正确的序列化/反序列化 LocalDateTime 呢？