redis编写lua脚本实现商品秒杀

编写lua脚本

--是否秒杀
local hasBuy = redis.call('sismember',KEYS[1],ARGV[1])
    if hasBuy~=0 then
    return 0;
end

--校验库存
for goodsIndex=2,#KEYS do
    local goodStock = redis.call('get',KEYS[goodsIndex])
    if tonumber(goodStock) < tonumber(ARGV[goodsIndex]) then
    return 2;
    end
end

--扣库存
for goodsIndex=2,#KEYS do
    redis.call('decrby',KEYS[goodsIndex],ARGV[goodsIndex])
end

--抢单成功
redis.call('sadd',KEYS[1],ARGV[1])
return 1

 

测试用例

Jedis jedis = jedisPool.getResource();
        jedis.select(2);

        String luaStr = "local hasBuy = redis.call('sismember',KEYS[1],ARGV[1])\n" +
                "if hasBuy~=0 then\n" +
                "return 0;\n" +
                "end \n"+
                "for goodsIndex=2,#KEYS do\n" +
                "    local goodStock = redis.call('get',KEYS[goodsIndex])\n" +
                "    local redisStock=ARGV[goodsIndex]\n"+
                "    if tonumber(goodStock) < tonumber(redisStock) then\n" +
                "    return 2;\n" +
                "    end\n" +
                "end\n"+
                "for goodsIndex=2,#KEYS do\n" +
                "redis.call('decrby',KEYS[goodsIndex],ARGV[goodsIndex])\n" +
                "end\n"+
                "redis.call('sadd',KEYS[1],ARGV[1])\n" +
                "return 1";


        List<String> keys = new ArrayList<>();
        keys.add("user_id");
        //商品ID
        keys.add("1001");
        keys.add("1002");
        keys.add("1003");


        List<String> values = new ArrayList<>();
        values.add(userId);
        //商品购买量
        values.add(goodsNums.get(0));
        values.add(goodsNums.get(1));
        values.add(goodsNums.get(2));

        Object result = jedis.eval(luaStr, keys,values);

        System.out.println("redis返回  result: " + result);

        if (jedis != null) {
            jedis.close();
        }

 

测试数据的话，本身手动加几条

redis.set(1001,100)
redis.set(1002,100)
redis.set(1003,100)

 

已经秒杀的用户返回 0 

秒杀成功返回 1

库存不足返回 2

参考：

https://blog.csdn.net/u010800970/article/details/81834965

https://blog.csdn.net/zhurhyme/article/details/79046470