// 假设这是从前端获取的时间字符串 日期String 转date
String dateString = costSharingVo.getExpenseTime();
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd"); // 根据实际格式调整
LocalDate localDate = LocalDate.parse(dateString, formatter);
Date date = Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant());