工作中redis锁的问题记录

受到公司刚大佬的影响，说了很多关于写总结的好处，于是我就试着写一写

。

上次上线的新车2,版本，有这么一个问题，我们服务端给app提供了一个上传图片的接口，图片是接受参数是一个数组，意思是等图片上传完之后，统一将图片id给我们就好了，但是因为上传接货单的上限是50张图片，所有如果一次就将图片全部上传并调用我们接口的话，app那边反应将会很慢，所以最后定的方案就是上传一张接货单就调用我们一次接口。

我们服务这边，是第一次上传借货单的时候就去创建一张接货单审核单，一个物流单对应一个物流单审核单，意味着一次上传的图片都挂在接货单审核单下面，因为app那边是上传接货单的时候是上传一次就掉一次接口，所以这里存在高并发的问题，第一次的代码是这个样的。

/**
* 批量上传接货单
*
* @param orderID
* @param detailBos
* @throws BusinessException
*/
@Override
public void mutilCreateReceiveOrder(Integer orderID, List<FreshCarReceivingGoodsPhotoDetailBo> detailBos) throws BusinessException {
if (orderID == null || detailBos == null){
throw new BusinessException("订单ID或者接货单不能为空");
}

//创建一张接货单审核单
FreshCarReceivGoodsBo freshCarReceivGoodsBo = new FreshCarReceivGoodsBo();
freshCarReceivGoodsBo.setOrderID(orderID);
Integer recID = this.create(freshCarReceivGoodsBo);

//填充到接货单集合中
List<FreshCarReceivingGoodsPhotoDetailBo> list = new ArrayList<>();
for (FreshCarReceivingGoodsPhotoDetailBo bo: detailBos){
if (bo == null){
continue;
}
bo.setReceivGoodsID(recID);
bo.setIsDelete(false);
bo.setCreateTime(new Date());
list.add(bo);
}

freshCarReceivingGoodsPhotoDetailDomain.create(list);
}

/**
* 创建收货审核单
*
* @param freshCarReceivGoodsBo
* @return
* @throws BusinessException
*/
@Override
public Integer create(FreshCarReceivGoodsBo freshCarReceivGoodsBo) throws BusinessException {
if (freshCarReceivGoodsBo == null){
throw new BusinessException("收货审核单不能为空");
}
FreshCarReceivGoods freshCarReceivGoods = BeanUtil.convert(freshCarReceivGoodsBo,FreshCarReceivGoods.class);

Integer orderID = freshCarReceivGoods.getOrderID();
if (orderID == null ){
throw new BusinessException("订单ID不能为空");
}
//查询该订单下是否存在收货审核单
RedisLock lock = null;

try {
lock = redisUtil.initLock(RedisKeyConstant.getKey(RedisKeyConstant.Business.COMMON, RedisKeyConstant.Project.COMMON,
orderID.toString())); //获取锁
if(lock.lock(1000)){
FreshCarReceivGoodsBo  bo = this.getByOrderID(orderID);
if (bo != null){
if (bo.getCheckStatus().equals(ReceiveStatusEnums.ReceiveCheckStatusEnum.WAITCHECK) ||
bo.getCheckStatus().equals(ReceiveStatusEnums.ReceiveCheckStatusEnum.SAVE)) {
return bo.getID();
}
if (bo.getCheckStatus().equals(ReceiveStatusEnums.ReceiveCheckStatusEnum.PASS)){
throw new BusinessException("该订单已存在审核通过的接货审核单，无法再创建");
}
}
//初始状态为保存
freshCarReceivGoods.setCheckStatus(ReceiveStatusEnums.ReceiveCheckStatusEnum.SAVE.getValue());
freshCarReceivGoods.setCreateTime(new Date());
freshCarReceivGoods.setIsDelete(false);

//保存
return freshCarReceivGoodsService.save(freshCarReceivGoods);

}else{
throw new BusinessException("get lock fail");
}
} finally {
if (null != lock) {
lock.unlock();
}
}

这样写的话，发现后面还是会一次上传还是会创建两张相同时间的接货单审核单。

问题分析：

这个代码的锁的范围只是在创建接货单审核单的地方，而且而且创建借货单审核单，和保存图片是在同一个domain里面，所以是在同一个事务下面，当两个线程同时进来的时候，一个线程被挡住，一个进程进去创建了审核单，但是这个时候事务并没有提交，等第二个线程进来的时候，根本在数据库里面查不到记录，所以又创建了一遍，所以后台才会出现有两个审核单的情况。

问题解决：

最后我们是这样解决的，我们将锁的范围扩大，将创建借货单审核单和保存接货单信息放在同一个锁里面，而且是在同一个事务下面，这个的缺点是相应时间会长，但是能避免创建两个接货单审核单的情况。

代码如下：

/**
* 批量上传接货单
*
* @param orderID
* @param detailBos
* @throws BusinessException
*/
@Override
public void mutilCreateReceiveOrder(Integer orderID, List<FreshCarReceivingGoodsPhotoDetailBo> detailBos) throws BusinessException {
if (orderID == null || detailBos == null){
throw new BusinessException("订单ID或者接货单不能为空");
}

RedisLock lock = null;

try {
lock = redisUtil.initLock(RedisKeyConstant.getKey(RedisKeyConstant.Business.COMMON, RedisKeyConstant.Project.COMMON,
"freshCar_order_"+orderID.toString()));
if(lock.lock(2000)){
//创建一张接货单审核单
FreshCarReceivGoodsBo freshCarReceivGoodsBo = new FreshCarReceivGoodsBo();
freshCarReceivGoodsBo.setOrderID(orderID);
Integer recID = this.create(freshCarReceivGoodsBo);

//填充到接货单集合中
List<FreshCarReceivingGoodsPhotoDetailBo> list = new ArrayList<>();
for (FreshCarReceivingGoodsPhotoDetailBo bo: detailBos){
if (bo == null){
continue;
}
bo.setReceivGoodsID(recID);
bo.setIsDelete(false);
bo.setCreateTime(new Date());
list.add(bo);
}

freshCarReceivingGoodsPhotoDetailDomain.create(list);
}else{
throw new BusinessException("get lock fail");
}
} finally {
if (null != lock) {
lock.unlock();
}
}
}