使用lua+redis解决发多张券的并发问题

public boolean sendCoupons(Long userId, Long couponId) {
 // 一堆校验
 // ...
 // 查出券码
 List<CouponCode> couponCodes = couponCodeService.findByCouponId(couponId, num);
 // batchUpdateStatus是一个被@Transactional(propagation = Propagation.REQUIRES_NEW)修饰的方法
 // 批量更新为已被领取状态
 couponCodeService.batchUpdateStatus(couponCods);
 // 发券
 // 发权益
 // 新增用户券码领取记录
}

local result = {}
for i=1,ARGV[1],1 do
 result[i] = redis.call("lpop", KEYS[1])
end
return table.contact(result , "|")

@Slf4j
@Component
public class CouponCodeRedisQueueClient implements InitializingBean {

 /**
  * redis lua脚本文件路径
  */
 public static final String POP_COUPON_CODE_LUA_PATH = "lua/pop-coupon-code.lua";
 public static final String SEPARATOR = "|";

 private static final String COUPON_CODE_KEY_PATTERN = "PROMOTION:COUPON_CODE_{0}";
 private String LUA_COUPON_CODE_SCRIPT;

 private String LUA_COUPON_CODE_SCRIPT_SHA;

 @Autowired
 private JedisTemplate jedisTemplate;

 @Override
 public void afterPropertiesSet() throws Exception {

  LUA_COUPON_CODE_SCRIPT = Resources.toString(Resources.getResource(POP_COUPON_CODE_LUA_PATH), Charsets.UTF_8);
  if (StringUtils.isNotBlank(LUA_COUPON_CODE_SCRIPT)) {

   LUA_COUPON_CODE_SCRIPT_SHA = jedisTemplate.execute(jedis -> {
    return jedis.scriptLoad(LUA_COUPON_CODE_SCRIPT);
   });
   log.info("redis lock script sha:{}", LUA_COUPON_CODE_SCRIPT_SHA);
  }

 }

 /**
  * 获取Code
  *
  * @param activityId
  * @param num
  * @return
  */
 public List<String> popCouponCode(Long activityId, String num , int retryNum) {
  if(retryNum == 0){
   log.error("reload lua script error , try limit times ,activityId:{}", activityId);
   return Collections.emptyList();
  }
  List<String> keys = Lists.newArrayList();
  String key = buildKey(String.valueOf(activityId));
  keys.add(key);
  List<String> args = Lists.newArrayList();
  args.add(num);

  try {
   Object result = jedisTemplate.execute(jedis -> {
    if (StringUtils.isNotBlank(LUA_COUPON_CODE_SCRIPT_SHA)) {
     return jedis.evalsha(LUA_COUPON_CODE_SCRIPT_SHA, keys, args);
    } else {
     return jedis.eval(LUA_COUPON_CODE_SCRIPT, keys, args);
    }
   });
   log.info("pop coupon code by lua script.result:{}", result);
   if (Objects.isNull(result)) {
    return Collections.emptyList();
   }
   return Splitter.on(SEPARATOR).splitToList(result.toString());
  } catch (JedisNoScriptException jnse) {
   log.error("no lua lock script found.try to reload it", jnse);
   reloadLuaScript();
   //加载后重新执行
   popCouponCode(activityId, num, --retryNum);
  } catch (Exception e) {
   log.error("failed to get a redis lock.key:{}", key, e);
  }
  return Collections.emptyList();
 }

 /**
  * 重新加载LUA脚本
  *
  * @throws Exception
  */
 public void reloadLuaScript() {
  synchronized (CouponCodeRedisQueueClient.class) {
   try {
    afterPropertiesSet();
   } catch (Exception e) {
    log.error("failed to reload redis lock lua script.retry load it.");
    reloadLuaScript();
   }
  }
 }

 /**
  * 构建Key
  *
  * @param activityId
  * @return
  */
 public String buildKey(String activityId) {
  return MessageFormat.format(COUPON_CODE_KEY_PATTERN, activityId);
 }

}