从零搭建基于SpringBoot的秒杀系统(七)：高并发导致超卖问题分析处理

@RequestMapping(value = prefix+"/test/execute",method = RequestMethod.POST,consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
@ResponseBody
public BaseResponse testexecute(@RequestBody @Validated KillDto killDto, BindingResult result, HttpSession httpSession){
    if (result.hasErrors()||killDto.getKillid()<0){
        return new BaseResponse(StatusCode.InvalidParam);
    }
    try {
        Boolean res=killService.KillItem(killDto.getKillid(),killDto.getUserid());
        if (!res){
            return new BaseResponse(StatusCode.Fail.getCode(),"商品已经抢购完或您已抢购过该商品");
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    BaseResponse baseResponse=new BaseResponse(StatusCode.Success);
    baseResponse.setData("抢购成功");
    return baseResponse;
}

@Select("select \n" +
        "a.*,\n" +
        "b.name as itemName,\n" +
        "(\n" +
        "\tcase when(now() BETWEEN a.start_time and a.end_time and a.total>0)\n" +
        "\t\tthen 1\n" +
        "\telse 0\n" +
        "\tend\n" +
        ")as cankill\n" +
        "from item_kill as a left join item as b\n" +
        "on a.item_id = b.id\n" +
        "where a.is_active=1 and a.id=#{id} and a.total>0;")
ItemKill selectByidV2(Integer killId);
@Update("update item_kill set total=total-1 where id=#{killId} and total>0")
int updateKillItemV2(Integer killId);

//mysql优化
public Boolean KillItemV2(Integer killId, Integer userId) throws Exception {
    Boolean result=false;
    //判断当前用户是否抢购过该商品
    if (itemKillSuccessMapper.countByKillUserId(killId,userId)<=0){
        //获取商品详情
        ItemKill itemKill=itemKillMapper.selectByidV2(killId);
        if (itemKill!=null&&itemKill.getCanKill()==1 && itemKill.getTotal()>0){
            int res=itemKillMapper.updateKillItemV2(killId);
            if (res>0){
                commonRecordKillSuccessInfo(itemKill,userId);
                result=true;
            }
        }
    }else {
        System.out.println("您已经抢购过该商品");
    }
    return result;
}

public interface KillService {
    Boolean KillItem(Integer killId,Integer userId) throws Exception;
    Boolean KillItemV2(Integer killId,Integer userId) throws Exception;
}

//测试mysql优化的版本
@RequestMapping(value = prefix+"/test/execute2",method = RequestMethod.POST,consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
@ResponseBody
public BaseResponse testexecute2(@RequestBody @Validated KillDto killDto, BindingResult result, HttpSession httpSession){
    if (result.hasErrors()||killDto.getKillid()<0){
        return new BaseResponse(StatusCode.InvalidParam);
    }
    try {
        Boolean res=killService.KillItemV2(killDto.getKillid(),killDto.getUserid());
        if (!res){
            return new BaseResponse(StatusCode.Fail.getCode(),"商品已经抢购完或您已抢购过该商品");
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    BaseResponse baseResponse=new BaseResponse(StatusCode.Success);
    baseResponse.setData("抢购成功");
    return baseResponse;
}