文档 AWS SDK 示例 GitHub 存储库中还有更多 [S AWS DK 示例](https://github.com/awsdocs/aws-doc-sdk-examples)。

本文属于机器翻译版本。若本译文内容与英语原文存在差异，则一律以英文原文为准。

# `UpdateTimeToLive`与 AWS SDK 或 CLI 配合使用
<a name="dynamodb_example_dynamodb_UpdateTimeToLive_section"></a>

以下代码示例演示如何使用 `UpdateTimeToLive`。

操作示例是大型程序的代码摘录，必须在上下文中运行。在以下代码示例中，您可以查看此操作的上下文：
+  [使用直播和 Time-to-Live](dynamodb_example_dynamodb_Scenario_StreamsAndTTL_section.md) 

------
#### [ CLI ]

**AWS CLI**  
**更新表的生存时间设置**  
以下 `update-time-to-live` 示例在指定表上启用生存时间设置。  

```
aws dynamodb update-time-to-live \
    --table-name MusicCollection \
    --time-to-live-specification Enabled=true,AttributeName=ttl
```
输出：  

```
{
    "TimeToLiveSpecification": {
        "Enabled": true,
        "AttributeName": "ttl"
    }
}
```
有关更多信息，请参阅《Amazon DynamoDB 开发人员指南》**中的[生存时间](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/TTL.html)。  
+  有关 API 的详细信息，请参阅*AWS CLI 命令参考[UpdateTimeToLive](https://awscli.amazonaws.com/v2/documentation/api/latest/reference/dynamodb/update-time-to-live.html)*中的。

------
#### [ Java ]

**适用于 Java 的 SDK 2.x**  
使用 AWS SDK for Java 2.x在现有 DynamoDB 表上启用 TTL。  

```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.services.dynamodb.model.ResourceNotFoundException;
import software.amazon.awssdk.services.dynamodb.model.TimeToLiveSpecification;
import software.amazon.awssdk.services.dynamodb.model.UpdateTimeToLiveRequest;
import software.amazon.awssdk.services.dynamodb.model.UpdateTimeToLiveResponse;

import java.util.logging.Level;
import java.util.logging.Logger;

    public UpdateTimeToLiveResponse enableTTL(final String tableName, final String attributeName, final Region region) {
        final TimeToLiveSpecification ttlSpec = TimeToLiveSpecification.builder()
            .attributeName(attributeName)
            .enabled(true)
            .build();

        final UpdateTimeToLiveRequest request = UpdateTimeToLiveRequest.builder()
            .tableName(tableName)
            .timeToLiveSpecification(ttlSpec)
            .build();

        try (DynamoDbClient ddb = dynamoDbClient != null
            ? dynamoDbClient
            : DynamoDbClient.builder().region(region).build()) {
            return ddb.updateTimeToLive(request);
        } catch (ResourceNotFoundException e) {
            System.err.format(TABLE_NOT_FOUND_ERROR, tableName);
            throw e;
        } catch (DynamoDbException e) {
            System.err.println(e.getMessage());
            throw e;
        }
    }
```
使用 AWS SDK for Java 2.x在现有 DynamoDB 表上禁用 TTL。  

```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.services.dynamodb.model.ResourceNotFoundException;
import software.amazon.awssdk.services.dynamodb.model.TimeToLiveSpecification;
import software.amazon.awssdk.services.dynamodb.model.UpdateTimeToLiveRequest;
import software.amazon.awssdk.services.dynamodb.model.UpdateTimeToLiveResponse;

import java.util.logging.Level;
import java.util.logging.Logger;

    public UpdateTimeToLiveResponse disableTTL(
        final String tableName, final String attributeName, final Region region) {
        final TimeToLiveSpecification ttlSpec = TimeToLiveSpecification.builder()
            .attributeName(attributeName)
            .enabled(false)
            .build();

        final UpdateTimeToLiveRequest request = UpdateTimeToLiveRequest.builder()
            .tableName(tableName)
            .timeToLiveSpecification(ttlSpec)
            .build();

        try (DynamoDbClient ddb = dynamoDbClient != null
            ? dynamoDbClient
            : DynamoDbClient.builder().region(region).build()) {
            return ddb.updateTimeToLive(request);
        } catch (ResourceNotFoundException e) {
            System.err.format(TABLE_NOT_FOUND_ERROR, tableName);
            throw e;
        } catch (DynamoDbException e) {
            System.err.println(e.getMessage());
            throw e;
        }
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[UpdateTimeToLive](https://docs.aws.amazon.com/goto/SdkForJavaV2/dynamodb-2012-08-10/UpdateTimeToLive)*中的。

------
#### [ JavaScript ]

**适用于 JavaScript (v3) 的软件开发工具包**  
在现有 DynamoDB 表上启用 TTL。  

```
import { DynamoDBClient, UpdateTimeToLiveCommand } from "@aws-sdk/client-dynamodb";

export const enableTTL = async (tableName, ttlAttribute, region = 'us-east-1') => {

    const client = new DynamoDBClient({
        region: region,
        endpoint: `https://dynamodb.${region}.amazonaws.com`
    });

    const params = {
        TableName: tableName,
        TimeToLiveSpecification: {
            Enabled: true,
            AttributeName: ttlAttribute
        }
    };

    try {
        const response = await client.send(new UpdateTimeToLiveCommand(params));
        if (response.$metadata.httpStatusCode === 200) {
            console.log(`TTL enabled successfully for table ${tableName}, using attribute name ${ttlAttribute}.`);
        } else {
            console.log(`Failed to enable TTL for table ${tableName}, response object: ${response}`);
        }
        return response;
    } catch (e) {
        console.error(`Error enabling TTL: ${e}`);
        throw e;
    }
};

// Example usage (commented out for testing)
// enableTTL('ExampleTable', 'exampleTtlAttribute');
```
在现有 DynamoDB 表上禁用 TTL。  

```
import { DynamoDBClient, UpdateTimeToLiveCommand } from "@aws-sdk/client-dynamodb";

export const disableTTL = async (tableName, ttlAttribute, region = 'us-east-1') => {

    const client = new DynamoDBClient({
        region: region,
        endpoint: `https://dynamodb.${region}.amazonaws.com`
    });

    const params = {
        TableName: tableName,
        TimeToLiveSpecification: {
            Enabled: false,
            AttributeName: ttlAttribute
        }
    };

    try {
        const response = await client.send(new UpdateTimeToLiveCommand(params));
        if (response.$metadata.httpStatusCode === 200) {
            console.log(`TTL disabled successfully for table ${tableName}, using attribute name ${ttlAttribute}.`);
        } else {
            console.log(`Failed to disable TTL for table ${tableName}, response object: ${response}`);
        }
        return response;
    } catch (e) {
        console.error(`Error disabling TTL: ${e}`);
        throw e;
    }
};

// Example usage (commented out for testing)
// disableTTL('ExampleTable', 'exampleTtlAttribute');
```
+  有关 API 的详细信息，请参阅 *适用于 JavaScript 的 AWS SDK API 参考[UpdateTimeToLive](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/dynamodb/command/UpdateTimeToLiveCommand)*中的。

------
#### [ Python ]

**适用于 Python 的 SDK（Boto3）**  
在现有 DynamoDB 表上启用 TTL。  

```
import boto3


def enable_ttl(table_name, ttl_attribute_name):
    """
    Enables TTL on DynamoDB table for a given attribute name
        on success, returns a status code of 200
        on error, throws an exception

    :param table_name: Name of the DynamoDB table
    :param ttl_attribute_name: The name of the TTL attribute being provided to the table.
    """
    try:
        dynamodb = boto3.client("dynamodb")

        # Enable TTL on an existing DynamoDB table
        response = dynamodb.update_time_to_live(
            TableName=table_name,
            TimeToLiveSpecification={"Enabled": True, "AttributeName": ttl_attribute_name},
        )

        # In the returned response, check for a successful status code.
        if response["ResponseMetadata"]["HTTPStatusCode"] == 200:
            print("TTL has been enabled successfully.")
        else:
            print(
                f"Failed to enable TTL, status code {response['ResponseMetadata']['HTTPStatusCode']}"
            )
        return response
    except Exception as ex:
        print("Couldn't enable TTL in table %s. Here's why: %s" % (table_name, ex))
        raise


# your values
enable_ttl("your-table-name", "expireAt")
```
在现有 DynamoDB 表上禁用 TTL。  

```
import boto3


def disable_ttl(table_name, ttl_attribute_name):
    """
    Disables TTL on DynamoDB table for a given attribute name
        on success, returns a status code of 200
        on error, throws an exception

    :param table_name: Name of the DynamoDB table being modified
    :param ttl_attribute_name: The name of the TTL attribute being provided to the table.
    """
    try:
        dynamodb = boto3.client("dynamodb")

        # Enable TTL on an existing DynamoDB table
        response = dynamodb.update_time_to_live(
            TableName=table_name,
            TimeToLiveSpecification={"Enabled": False, "AttributeName": ttl_attribute_name},
        )

        # In the returned response, check for a successful status code.
        if response["ResponseMetadata"]["HTTPStatusCode"] == 200:
            print("TTL has been disabled successfully.")
        else:
            print(
                f"Failed to disable TTL, status code {response['ResponseMetadata']['HTTPStatusCode']}"
            )
    except Exception as ex:
        print("Couldn't disable TTL in table %s. Here's why: %s" % (table_name, ex))
        raise


# your values
disable_ttl("your-table-name", "expireAt")
```
+  有关 API 的详细信息，请参阅适用[UpdateTimeToLive](https://docs.aws.amazon.com/goto/boto3/dynamodb-2012-08-10/UpdateTimeToLive)于 *Python 的AWS SDK (Boto3) API 参考*。

------