Redis 实战------java版本代码优化

代码清单4-5 listItem()函数

原版代码：

    public boolean listItem(
            Jedis conn, String itemId, String sellerId, double price) {

        String inventory = "inventory:" + sellerId;
        String item = itemId + '.' + sellerId;
        long end = System.currentTimeMillis() + 5000;

        while (System.currentTimeMillis() < end) {
            conn.watch(inventory);
            if (!conn.sismember(inventory, itemId)){
                conn.unwatch();
                return false;
            }
            Transaction trans = conn.multi();
            trans.zadd("market:", price, item);
            trans.srem(inventory, itemId);
            List