Waiter 从版本 1 到版本 2 的变化 - AWS SDK for Java 2.x
高级别更改API 更改配置更改

Waiter 从版本 1 到版本 2 的变化

本主题详细介绍了 Waiter 的功能从版本 1（v1）到版本 2（v2）的变化。

下表展示了 DynamoDB Waiter 的具体差异。其他服务的 Waiter 也遵循同样的模式。

高级别更改

Waiter 类与服务位于相同的 Maven 构件中。

更改 v1 v2

Maven 依赖项

 
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.amazonaws</groupId>
            <artifactId>aws-java-sdk-bom</artifactId>
            <version>1.12.6801</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>
<dependencies>
    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>dynamodb</artifactId>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>software.amazon.awssdk</groupId>
            <artifactId>bom</artifactId>
            <version>2.27.102</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>
<dependencies>
    <dependency>
        <groupId>software.amazon.awssdk</groupId>
        <artifactId>dynamodb</artifactId>
    </dependency>
</dependencies>
软件包名称 com.amazonaws.services.dynamodbv2.waiters software.amazon.awssdk.services.dynamodb.waiters
类名

AmazonDynamoDBWaiters

1 最新版本。2 最新版本。

API 更改

更改 v1 v2
创建 Waiter 
AmazonDynamoDB client = AmazonDynamoDBClientBuilder 
                            .standard().build();
AmazonDynamoDBWaiters waiter = client.waiters();
 同步：
DynamoDbClient client = DynamoDbClient.create();
DynamoDbWaiter waiter = client.waiter();

异步：

DynamoDbAsyncClient asyncClient = 
        DynamoDbAsyncClient.create();
DynamoDbAsyncWaiter waiter = asyncClient.waiter();
等待表完成创建 同步：
waiter.tableExists()
    .run(new WaiterParameters<>(
        new DescribeTableRequest(tableName)));

异步：

waiter.tableExists()
    .runAsync(new WaiterParameters()
      .withRequest(new DescribeTableRequest(tableName)),
          new WaiterHandler() {
              @Override
              public void onWaitSuccess(
                  AmazonWebServiceRequest amazonWebServiceRequest) {
                    System.out.println("Table creation succeeded");
              }

              @Override
              public void onWaitFailure(Exception e) {
                  e.printStackTrace();
              }
          }).get();

同步：

WaiterResponse<DescribeTableResponse> waiterResponse =
    waiter.waitUntilTableExists(
        r -> r.tableName("myTable"));
waiterResponse.matched().response()
       .ifPresent(System.out::println);

异步：

waiter.waitUntilTableExists(r -> r.tableName(tableName))
           .whenComplete((r, t) -> {
               if (t != null) {
                   t.printStackTrace();
               } else {
                   System.out.println(
                        "Table creation succeeded");
               }
           }).join();

配置更改

更改 v1 v2
轮询策略（最大尝试次数和固定延迟） 
MaxAttemptsRetryStrategy maxAttemptsRetryStrategy = 
        new MaxAttemptsRetryStrategy(10);

FixedDelayStrategy fixedDelayStrategy = 
        new FixedDelayStrategy(3);

PollingStrategy pollingStrategy = 
        new PollingStrategy(maxAttemptsRetryStrategy, 
                fixedDelayStrategy);

waiter.tableExists().run(
        new WaiterParameters<>(
            new DescribeTableRequest(tableName)), 
                pollingStrategy);
 

FixedDelayBackoffStrategy fixedDelayBackoffStrategy = 
        FixedDelayBackoffStrategy
            .create(Duration.ofSeconds(3));

waiter.waitUntilTableExists(r -> r.tableName(tableName),
        c -> c.maxAttempts(10)
                .backoffStrategy(fixedDelayBackoffStrategy));