如何应对高并发下的购票压力

执行业务逻辑

com.damai.service.ProgramOrderService#create

在经过幂等、分布锁、业务验证后，开始执行真正的业务流程处理环节

public String create(ProgramOrderCreateDto programOrderCreateDto) {
    //从多级缓存中查找节目演出时间ProgramShowTime
    ProgramShowTime programShowTime =
            programShowTimeService.selectProgramShowTimeByProgramIdMultipleCache(programOrderCreateDto.getProgramId());
    //查询对应的票档类型
    List<TicketCategoryVo> getTicketCategoryList = 
            getTicketCategoryList(programOrderCreateDto,programShowTime.getShowTime());
    //传入的座位总价格
    BigDecimal parameterOrderPrice = new BigDecimal("0");
    //库中的座位总价格
    BigDecimal databaseOrderPrice = new BigDecimal("0");
    //要购买的座位
    List<SeatVo> purchaseSeatList = new ArrayList<>();
    //入参的座位
    List<SeatDto> seatDtoList = programOrderCreateDto.getSeatDtoList();
    //该节目下所有未售卖的座位
    List<SeatVo> seatVoList = new ArrayList<>();
    //该节目下的余票数量
    Map<String, Long> ticketCategoryRemainNumber = new HashMap<>(16);
    //遍历得到的票档
    for (TicketCategoryVo ticketCategory : getTicketCategoryList) {
        //从缓存中查询座位
        List<SeatVo> allSeatVoList = 
                seatService.selectSeatResolution(programOrderCreateDto.getProgramId(), ticketCategory.getId(), 
                        DateUtils.countBetweenSecond(DateUtils.now(), programShowTime.getShowTime()), TimeUnit.SECONDS);
        //将查询到未售卖的座位放入seatVoList
        seatVoList.addAll(allSeatVoList.stream().
                filter(seatVo -> seatVo.getSellStatus().equals(SellStatus.NO_SOLD.getCode())).toList());
        //将查询到的余票数量放入ticketCategoryRemainNumber   key:票档id  value:余票数量
        ticketCategoryRemainNumber.putAll(ticketCategoryService.getRedisRemainNumberResolution(
                programOrderCreateDto.getProgramId(),ticketCategory.getId()));
    }
    //入参座位存在
    if (CollectionUtil.isNotEmpty(seatDtoList)) {
        //余票数量检测 key：票档id  value：票档数量
        Map<Long, Long> seatTicketCategoryDtoCount = seatDtoList.stream()
                .collect(Collectors.groupingBy(SeatDto::getTicketCategoryId, Collectors.counting()));
        for (Entry<Long, Long> entry : seatTicketCategoryDtoCount.entrySet()) {
            Long ticketCategoryId = entry.getKey();
            Long purchaseCount = entry.getValue();
            //余票数量
            Long remainNumber = Optional.ofNullable(ticketCategoryRemainNumber.get(String.valueOf(ticketCategoryId)))
                    .orElseThrow(() -> new DaMaiFrameException(BaseCode.TICKET_CATEGORY_NOT_EXIST_V2));
            //如果购买数量大于余票数量，那么提示数量不足
            if (purchaseCount > remainNumber) {
                throw new DaMaiFrameException(BaseCode.TICKET_REMAIN_NUMBER_NOT_SUFFICIENT);
            }
        }
        //循环入参的座位对象
        for (SeatDto seatDto : seatDtoList) {
            //验证入参的对象在库中的状态，不存在、已锁、已售卖
            Map<String, SeatVo> seatVoMap = seatVoList.stream().collect(Collectors
                    .toMap(seat -> seat.getRowCode() + "-" + seat.getColCode(), seat -> seat, (v1, v2) -> v2));
            SeatVo seatVo = seatVoMap.get(seatDto.getRowCode() + "-" + seatDto.getColCode());
            //如果入参的座位在未售卖的座位中不存在，那么直接抛出异常提示
            if (Objects.isNull(seatVo)) {
                throw new DaMaiFrameException(BaseCode.SEAT_IS_NOT_NOT_SOLD);
            }
            purchaseSeatList.add(seatVo);
            //将入参的座位价格进行累加
            parameterOrderPrice = parameterOrderPrice.add(seatDto.getPrice());
            //将库中的座位价格进行类型
            databaseOrderPrice = databaseOrderPrice.add(seatVo.getPrice());
        }
        //传入的座位价格累加不能大于存放的相应座位累加价格
        if (parameterOrderPrice.compareTo(databaseOrderPrice) > 0) {
            throw new DaMaiFrameException(BaseCode.PRICE_ERROR);
        }
    }else {
        //入参座位不存在，利用算法自动根据人数和票档进行分配相邻座位
        Long ticketCategoryId = programOrderCreateDto.getTicketCategoryId();
        Integer ticketCount = programOrderCreateDto.getTicketCount();
        //余票检测
        Long remainNumber = Optional.ofNullable(ticketCategoryRemainNumber.get(String.valueOf(ticketCategoryId)))
                .orElseThrow(() -> new DaMaiFrameException(BaseCode.TICKET_CATEGORY_NOT_EXIST_V2));
        //如果购票的数量大于余票数量，则直接抛出异常提示
        if (ticketCount > remainNumber) {
            throw new DaMaiFrameException(BaseCode.TICKET_REMAIN_NUMBER_NOT_SUFFICIENT);
        }
        //用算法匹配座位
        purchaseSeatList = SeatMatch.findAdjacentSeatVos(seatVoList.stream().filter(seatVo ->
                Objects.equals(seatVo.getTicketCategoryId(), ticketCategoryId)).collect(Collectors.toList()), ticketCount);
        //如果匹配出来的座位数量小于要购买的数量，拒绝执行
        if (purchaseSeatList.size() < ticketCount) {
            throw new DaMaiFrameException(BaseCode.SEAT_OCCUPY);
        }
    }
    //进行操作缓存中的数据
    updateProgramCacheDataResolution(programOrderCreateDto.getProgramId(),purchaseSeatList,OrderStatus.NO_PAY);
    //将筛选出来的购买的座位信息传入，执行创建订单的操作
    return doCreate(programOrderCreateDto,purchaseSeatList);
}

获取节目演出时间

先从缓存中获取获取 节目演出时间ProgramShowTime，此数据在查询节目详情的时候放入了进去，所以这里一定会存在