Redis実戦------javaバージョンコード最適化

4324 ワード
redis
コードリスト4-5 listItem()関数
原版コード:
    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 results = trans.exec();
            // null response indicates that the transaction was aborted due to
            // the watched key changing.
            if (results == null){
                continue;
            }
            return true;
        }
        return false;
    }

実際のプロジェクトで実行される改善コード
public boolean listItem(Jedis conn, String itemId, String sellerId, double price) {
        //1.       ：       key 
        String  inventory=new StringBuffer().append("inventory:").append(sellerId).toString();
        String  item=new StringBuffer().append(itemId).append(".").append(sellerId).toString();   
        long end = System.currentTimeMillis() + 5000;
        while (System.currentTimeMillis() < end) {
            //2.         
            conn.watch(inventory);
            //3.                       
            if (!conn.sismember(inventory, itemId)){
                conn.unwatch();
                return false;
            }
            //            ，    
            Transaction trans = conn.multi();
            //           
            trans.zadd("market:", price, item);
            //          
            trans.srem(inventory, itemId);
            //    
            List results = trans.exec();
            // null response indicates that the transaction was aborted due to
            // the watched key changing.
            //          
            if (results == null){
                //      ，      
                continue;
            }
            //      ，  
            return true;
        }
        conn.close();
        //  
        return false;
    }
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