private void merge(BTreeNode leftNode,BTreeNode rightNode,int k){
        int t = leftNode.getT();
        int[] mergekeyList = new int[2 * t - 1];
        int[] leftKeys = leftNode.getKeyList();
        int[] rightKeys = rightNode.getKeyList();
        //key合并
        for (int i = 0; i < mergekeyList.length; i++)
        {
            if (i < t - 1)
            {
                mergekeyList[i] = leftKeys[i];
            }
            else if (i == t - 1)
            {
                mergekeyList[i] = k;
            }
            else
            {
                mergekeyList[i] = rightKeys[i - t + 2];
            }
            
        }
        
        //子树合并
        BTreeNode[] mergeBTreeNodes = new BTreeNode[2*t];
        BTreeNode[] leftSubNodes = leftNode.getSubTreeNodeList();
        BTreeNode[] rightSubNode = rightNode.getSubTreeNodeList();
        for (int i = 0; i < mergeBTreeNodes.length; i++)
        {
            if (i < t)
            {
                mergeBTreeNodes[i] = leftSubNodes[i];
            }else
            {
                mergeBTreeNodes[i] = rightSubNode[i - t];
            }
            
        }
        
        leftNode.setKeyList(mergekeyList);
        leftNode.setSubTreeNodeList(mergeBTreeNodes);
        
    }