lua脚本操作Redis

一次扣减一个商品库存

**  //扣减库存@Testvoid test2() throws IOException {valueOperations.set(key,15L);StringBuilder sb = new StringBuilder();sb.append(" local key = KEYS[1]  ");sb.append(" local qty = ARGV[1]  ");sb.append(" local redis_qty = redis.call('get',key)  ");sb.append(" if tonumber(redis_qty) >= tonumber(qty) then  ");sb.append("   redis.call('decrby',key,qty) ");sb.append("  return  -1  ");sb.append(" else  ");sb.append("  return tonumber(redis_qty) ");  //  0, 1,2,3 ....sb.append(" end  ");sb.append("   ");RedisScript<Long> script = RedisScript.of(sb.toString(),Long.class);ExecutorService executorService = Executors.newCachedThreadPool();for (int i = 1; i <= 10; i++) {int finalI = i;executorService.execute(()->{int needQty = RandomUtil.randomInt(1, 5);Long qty =  stringRedisTemplate.execute(script, CollUtil.newArrayList(key), needQty+"");if(qty.intValue() == -1 ){System.out.println("线程"+ finalI +"扣减成功,需求量是："+needQty);} else {System.out.println("线程"+ finalI +"扣减失败,当前库存变量是："+qty);}});}System.in.read();}

一次扣减多个商品的库存

void test4()  {StringBuilder sb = new StringBuilder();sb.append(" local table = {}  "); // 你要扣减的key ：product.1sb.append(" local values =  redis.call('mget',  unpack(KEYS) )"); // [product.1,product.2]   =>  product.1 product.2sb.append(" for i = 1, #KEYS   do  ");sb.append("   if  tonumber(ARGV[i]) > tonumber(values[i])   then ");sb.append("     table[#table + 1] =  KEYS[i] .. '=' .. values[i] "); // product.1=23sb.append("   end ");sb.append(" end ");sb.append(" if #table > 0 then ");sb.append("   return table  ");sb.append(" end ");sb.append(" for i = 1 , #KEYS do ");sb.append("   redis.call('decrby',KEYS[i],ARGV[i])  ");sb.append(" end ");sb.append(" return {} ");RedisScript<List> luaScript = RedisScript.of(sb.toString(), List.class);List<StockProduct> stockProducts =  new ArrayList<>();stockProducts.add(new StockProduct(5,1));stockProducts.add(new StockProduct(4,2));List<String> keys = stockProducts.stream().map(it -> "product." + it.getId()).collect(Collectors.toList());Object[] qtys = stockProducts.stream().map(it -> it.getQty() + "").toArray();List<String> list = stringRedisTemplate.execute(luaScript,keys,qtys);if(list.isEmpty()){System.out.println("库存冻结成功");} else {for (String key_qty : list) {String[] split = key_qty.split("=");System.out.println(split[0] + "库存不足，剩余库存量：" + split[1]);}}ThreadUtil.safeSleep(3000);}