try (TransportClient client = createClientSingle()) {
            //创建索引库 并执行
            //admin()即admin对象;
            //indices索引库管理;
            //prepareCreate准备创建索引库"indexTest"
            AcknowledgedResponse response = client.admin().indices().prepareDelete("indexTest").execute().actionGet();
            return response.toString();
        } catch (Exception e) {
            e.printStackTrace();
            return e.getMessage();
        }