第 2 步：测试与分类账的连接

重要

终止支持通知：现有客户将能够使用亚马逊，QLDB直到 2025 年 7 月 31 日终止支持。有关更多详细信息，请参阅将亚马逊QLDB账本迁移到亚马逊 Aurora Postgr SQL e。

在此步骤中，您将验证是否可以使用交易数据API终端节点连接到 Amazon QLDB 中的vehicle-registration账本。

测试与分类账的连接

1. 使用以下程序（ConnectToLedger.ts），该程序创建了与vehicle-registration 分类账的数据会话连接。

   2.x

   /*
    * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
    * SPDX-License-Identifier: MIT-0
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy of this
    * software and associated documentation files (the "Software"), to deal in the Software
    * without restriction, including without limitation the rights to use, copy, modify,
    * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
    * permit persons to whom the Software is furnished to do so.
    *
    * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
    * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
    * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
    * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    */
   
   import { QldbDriver, RetryConfig  } from "amazon-qldb-driver-nodejs";
   import { ClientConfiguration } from "aws-sdk/clients/qldbsession";
   
   import { LEDGER_NAME } from "./qldb/Constants";
   import { error, log } from "./qldb/LogUtil";
   
   const qldbDriver: QldbDriver = createQldbDriver();
   
   /**
    * Create a driver for creating sessions.
    * @param ledgerName The name of the ledger to create the driver on.
    * @param serviceConfigurationOptions The configurations for the AWS SDK client that the driver uses.
    * @returns The driver for creating sessions.
    */
   export function createQldbDriver(
       ledgerName: string = LEDGER_NAME,
       serviceConfigurationOptions: ClientConfiguration = {}
   ): QldbDriver {
       const retryLimit = 4;
       const maxConcurrentTransactions = 10;
       //Use driver's default backoff function (and hence, no second parameter provided to RetryConfig)
       const retryConfig: RetryConfig = new RetryConfig(retryLimit);
       const qldbDriver: QldbDriver = new QldbDriver(ledgerName, serviceConfigurationOptions, maxConcurrentTransactions, retryConfig);
       return qldbDriver;
   }
   
   export function getQldbDriver(): QldbDriver {
       return qldbDriver;
   }
   
   /**
    * Connect to a session for a given ledger using default settings.
    * @returns Promise which fulfills with void.
    */
   const main = async function(): Promise<void> {
       try {
           log("Listing table names...");
           const tableNames: string[] = await qldbDriver.getTableNames();
           tableNames.forEach((tableName: string): void => {
               log(tableName);
           });
       } catch (e) {
           error(`Unable to create session: ${e}`);
       }
   }
   
   if (require.main === module) {
       main();
   }

   1.x

   /*
    * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
    * SPDX-License-Identifier: MIT-0
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy of this
    * software and associated documentation files (the "Software"), to deal in the Software
    * without restriction, including without limitation the rights to use, copy, modify,
    * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
    * permit persons to whom the Software is furnished to do so.
    *
    * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
    * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
    * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
    * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    */
   
   import { QldbDriver  } from "amazon-qldb-driver-nodejs";
   import { ClientConfiguration } from "aws-sdk/clients/qldbsession";
   
   import { LEDGER_NAME } from "./qldb/Constants";
   import { error, log } from "./qldb/LogUtil";
   
   const qldbDriver: QldbDriver = createQldbDriver();
   
   /**
    * Create a driver for creating sessions.
    * @param ledgerName The name of the ledger to create the driver on.
    * @param serviceConfigurationOptions The configurations for the AWS SDK client that the driver uses.
    * @returns The driver for creating sessions.
    */
   export function createQldbDriver(
       ledgerName: string = LEDGER_NAME,
       serviceConfigurationOptions: ClientConfiguration = {}
   ): QldbDriver {
       const qldbDriver: QldbDriver = new QldbDriver(ledgerName, serviceConfigurationOptions);
       return qldbDriver;
   }
   
   export function getQldbDriver(): QldbDriver {
       return qldbDriver;
   }
   
   /**
    * Connect to a session for a given ledger using default settings.
    * @returns Promise which fulfills with void.
    */
   var main = async function(): Promise<void> {
       try {
           log("Listing table names...");
           const tableNames: string[] = await qldbDriver.getTableNames();
           tableNames.forEach((tableName: string): void => {
               log(tableName);
           });
       } catch (e) {
           error(`Unable to create session: ${e}`);
       } 
   }
   
   if (require.main === module) {
       main();
   }

   注意

   要在账本上运行数据交易，您必须创建一个QLDB驱动程序对象以连接到指定的账本。这与您在 上一步 中创建分类账时使用的 qldbClient 客户端对象不同。之前的客户机仅用于运行中列出的管理API操作亚马逊QLDBAPI参考资料。

2. 要运行编译后的程序，请输入以下命令。

   node dist/ConnectToLedger.js

要在 vehicle-registration 分类账中创建表，请继续 步骤 3：创建表、索引与示例数据。