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# 使用软件开发工具包通过 Amazon S3 向亚马逊 SNS 发布一条大消息 AWS
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以下代码示例演示了如何使用 Amazon S3 向 Amazon SNS 发布大型消息来存储消息负载。

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#### [ Java ]

**适用于 Java 的 SDK 1.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/java/example_code/sns#code-examples)中查找完整示例，了解如何进行设置和运行。
要发布大型消息，请使用适用于 Java 的 Amazon SNS 扩展客户端库。您发送的消息将引用包含实际消息内容的 Amazon S3 对象。  

```
import com.amazon.sqs.javamessaging.AmazonSQSExtendedClient;
import com.amazon.sqs.javamessaging.ExtendedClientConfiguration;
import com.amazonaws.regions.Region;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.sns.AmazonSNS;
import com.amazonaws.services.sns.AmazonSNSClientBuilder;
import com.amazonaws.services.sns.model.CreateTopicRequest;
import com.amazonaws.services.sns.model.PublishRequest;
import com.amazonaws.services.sns.model.SetSubscriptionAttributesRequest;
import com.amazonaws.services.sns.util.Topics;
import com.amazonaws.services.sqs.AmazonSQS;
import com.amazonaws.services.sqs.AmazonSQSClientBuilder;
import com.amazonaws.services.sqs.model.CreateQueueRequest;
import com.amazonaws.services.sqs.model.ReceiveMessageResult;
import software.amazon.sns.AmazonSNSExtendedClient;
import software.amazon.sns.SNSExtendedClientConfiguration;

public class Example {

        public static void main(String[] args) {
                final String BUCKET_NAME = "extended-client-bucket";
                final String TOPIC_NAME = "extended-client-topic";
                final String QUEUE_NAME = "extended-client-queue";
                final Regions region = Regions.DEFAULT_REGION;

                // Message threshold controls the maximum message size that will be allowed to
                // be published
                // through SNS using the extended client. Payload of messages exceeding this
                // value will be stored in
                // S3. The default value of this parameter is 256 KB which is the maximum
                // message size in SNS (and SQS).
                final int EXTENDED_STORAGE_MESSAGE_SIZE_THRESHOLD = 32;

                // Initialize SNS, SQS and S3 clients
                final AmazonSNS snsClient = AmazonSNSClientBuilder.standard().withRegion(region).build();
                final AmazonSQS sqsClient = AmazonSQSClientBuilder.standard().withRegion(region).build();
                final AmazonS3 s3Client = AmazonS3ClientBuilder.standard().withRegion(region).build();

                // Create bucket, topic, queue and subscription
                s3Client.createBucket(BUCKET_NAME);
                final String topicArn = snsClient.createTopic(
                                new CreateTopicRequest().withName(TOPIC_NAME)).getTopicArn();
                final String queueUrl = sqsClient.createQueue(
                                new CreateQueueRequest().withQueueName(QUEUE_NAME)).getQueueUrl();
                final String subscriptionArn = Topics.subscribeQueue(
                                snsClient, sqsClient, topicArn, queueUrl);

                // To read message content stored in S3 transparently through SQS extended
                // client,
                // set the RawMessageDelivery subscription attribute to TRUE
                final SetSubscriptionAttributesRequest subscriptionAttributesRequest = new SetSubscriptionAttributesRequest();
                subscriptionAttributesRequest.setSubscriptionArn(subscriptionArn);
                subscriptionAttributesRequest.setAttributeName("RawMessageDelivery");
                subscriptionAttributesRequest.setAttributeValue("TRUE");
                snsClient.setSubscriptionAttributes(subscriptionAttributesRequest);

                // Initialize SNS extended client
                // PayloadSizeThreshold triggers message content storage in S3 when the
                // threshold is exceeded
                // To store all messages content in S3, use AlwaysThroughS3 flag
                final SNSExtendedClientConfiguration snsExtendedClientConfiguration = new SNSExtendedClientConfiguration()
                                .withPayloadSupportEnabled(s3Client, BUCKET_NAME)
                                .withPayloadSizeThreshold(EXTENDED_STORAGE_MESSAGE_SIZE_THRESHOLD);
                final AmazonSNSExtendedClient snsExtendedClient = new AmazonSNSExtendedClient(snsClient,
                                snsExtendedClientConfiguration);

                // Publish message via SNS with storage in S3
                final String message = "This message is stored in S3 as it exceeds the threshold of 32 bytes set above.";
                snsExtendedClient.publish(topicArn, message);

                // Initialize SQS extended client
                final ExtendedClientConfiguration sqsExtendedClientConfiguration = new ExtendedClientConfiguration()
                                .withPayloadSupportEnabled(s3Client, BUCKET_NAME);
                final AmazonSQSExtendedClient sqsExtendedClient = new AmazonSQSExtendedClient(sqsClient,
                                sqsExtendedClientConfiguration);

                // Read the message from the queue
                final ReceiveMessageResult result = sqsExtendedClient.receiveMessage(queueUrl);
                System.out.println("Received message is " + result.getMessages().get(0).getBody());
        }
}
```

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有关 S AWS DK 开发者指南和代码示例的完整列表，请参阅[将 Amazon SNS 与软件开发工具包配合使用 AWS](sdk-general-information-section.md)。本主题还包括有关入门的信息以及有关先前的 SDK 版本的详细信息。