要使用Alpakka从S3存储桶中进行对象流式传输，您需要在项目中添加以下依赖项：

    com.lightbend.akka
    akka-stream-alpakka-s3_2.13
    3.1.2

然后，您可以使用以下示例代码从S3存储桶中流式传输对象：

import akka.actor.ActorSystem;
import akka.stream.ActorMaterializer;
import akka.stream.alpakka.s3.S3Settings;
import akka.stream.alpakka.s3.javadsl.S3;
import akka.stream.javadsl.Source;
import akka.util.ByteString;
import software.amazon.awssdk.services.s3.S3AsyncClient;
import software.amazon.awssdk.services.s3.model.GetObjectRequest;
import software.amazon.awssdk.services.s3.model.S3Object;

import java.util.concurrent.CompletionStage;

public class S3ObjectStreamingExample {

    public static void main(String[] args) {
        // Create an Akka actor system and materializer
        ActorSystem system = ActorSystem.create();
        ActorMaterializer materializer = ActorMaterializer.create(system);
        
        // Create an S3AsyncClient
        S3AsyncClient s3Client = S3AsyncClient.create();

        // Define the S3 bucket and object key
        String bucket = "your-bucket-name";
        String key = "your-object-key";

        // Create S3 settings
        S3Settings s3Settings = S3Settings.create(system);

        // Create a source for streaming the S3 object
        Source> source = S3.download(bucket, key)
                .withAttributes(S3Attributes.settings(s3Settings))
                .map(S3Object::toBuilder)
                .map(builder -> builder.responseTransformer(response -> response.toBuilder()
                        .content(response.content().map(content -> content.toBuilder()
                                .subscriber(content.asSubscriber())
                                .build()))
                        .build()))
                .map(S3Object.Builder::build)
                .mapMaterializedValue(completionStage -> completionStage.thenApply(response -> response.object()));

        // Run the source and consume the streamed data
        source.runForeach(byteString -> {
            // Process each chunk of data here
            System.out.println("Received chunk of data: " + byteString.utf8String());
        }, materializer)
        .thenRun(system::terminate);
    }
}

请确保替换示例代码中的your-bucket-name和your-object-key为实际的存储桶名称和对象键。

此示例使用Akka Stream Alpakka提供的S3.download方法创建一个从S3存储桶中下载对象的Source。然后，您可以使用runForeach方法消耗流式传输的字节数据，并在其中处理每个数据块。

最后，使用system.terminate()方法终止Actor系统。

请注意，此示例假设您已经正确配置了AWS凭证以访问S3存储桶。