Redis学习笔记2——黑马点评Stream消息队列实现异步秒杀下单

lua：

local voucherId=ARGV[1]

local userId=ARGV[2]

local orderId=ARGV[3]  

local stockKey='seckill:stock:'..voucherId

local orderKey='seckill:order:'..voucherId

if(tonumber(redis.call('get',stockKey))<=0) then
    return 1
end

if(redis.call('sismember',orderKey,userId)==1) then
    return 2
end

redis.call('incrby',stockKey,-1)

redis.call('sadd',orderKey,userId)

redis.call('xadd','stream.orders','*','userId',userId,'voucherId',voucherId,'id',orderId) 

return 0

VoucherOrderServiceImpl：

public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    IVoucherOrderService proxy_plus;

    private static final DefaultRedisScript<Long> SECKILL_Script;
    static{
        SECKILL_Script=new DefaultRedisScript<>();
        SECKILL_Script.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_Script.setResultType(Long.class);
    }

    private static final ExecutorService SECKILL_ORDER_EXECUTOR=Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherHandler());
    }

    private class VoucherHandler implements Runnable{
        @Override
        public void run(){
            while(true){
                try {
                    //从stream队列里取出一个消息: xreadgroup group g1 c1 count 1 block 2000 streams stream.orders >
                    List<MapRecord<String, Object, Object>> readlist = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );

                    //判断消息是否为空
                    if(readlist==null || readlist.isEmpty()){
                        continue;
                    }

                    //不为空的话用此消息生成预备订单
                    MapRecord<String, Object, Object> record = readlist.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);

                    //处理预备订单
                    proxy_plus.createVoucherOrder_plus(voucherOrder);

                    //确认消息：sack stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge("stream.orders","g1",record.getId());

                } catch (Exception e) {
                    log.error("处理订单异常...");
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    //从pendinglist中里取出一个消息:xreadgroup group g1 c1 count 1 block 2000 streams stream.orders 0
                    List<MapRecord<String, Object, Object>> readlist = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create("stream.orders", ReadOffset.from("0"))
                    );

                    //判断消息是否为空，为空说明没有异常消息（即消息都读完确认了，已经移出了pendinglist）
                    if (readlist == null || readlist.isEmpty()) {
                        break;
                    }

                    //不为空的话用此消息生成预备订单
                    MapRecord<String, Object, Object> record = readlist.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);

                    //处理预备订单
                    proxy_plus.createVoucherOrder_plus(voucherOrder);

                    //确认消息：sack stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge("stream.orders", "g1", record.getId());

                } catch (Exception e) {
                    log.error("处理订单异常...");
                }
            }
        }
    }

    @Transactional
    public void createVoucherOrder_plus(VoucherOrder voucherOrder){
        seckillVoucherService.update()
                .setSql("stock=stock-1")
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0)
                .update();
        save(voucherOrder);
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        long orderId = redisIdWorker.nextId("order");

        //执行lua
        Long userId = UserHolder.getUser().getId();
        Long result = stringRedisTemplate.execute(
                SECKILL_Script,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );
        int r=result.intValue();

        //不能购买
        if(r==1){
            return Result.fail("库存不足！");
        }
        if(r==2){
            return Result.fail("不能重复购买！");
        }

        //能购买
        proxy_plus=(IVoucherOrderService) AopContext.currentProxy();

        return Result.ok(orderId);
    }
}