AWS S3（Amazon Simple Storage Service）是一种对象存储服务，可以存储和检索大量数据。要实现AWS S3的横向扩展连接，可以使用AWS SDK提供的API进行操作。下面是一个使用Java SDK的示例代码：

import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.*;

import java.util.List;

public class S3Example {
    public static void main(String[] args) {
        // 配置AWS凭证和区域
        S3Client s3Client = S3Client.builder()
                .region(Region.US_EAST_1)
                .credentialsProvider(DefaultCredentialsProvider.create())
                .build();

        // 列出所有存储桶
        ListBucketsResponse listBucketsResponse = s3Client.listBuckets();
        List buckets = listBucketsResponse.buckets();
        for (Bucket bucket : buckets) {
            System.out.println("Bucket: " + bucket.name());
        }

        // 创建存储桶
        String bucketName = "my-bucket";
        s3Client.createBucket(CreateBucketRequest.builder().bucket(bucketName).build());
        System.out.println("Bucket created: " + bucketName);

        // 上传对象
        String objectKey = "my-object";
        String objectData = "Hello, S3!";
        s3Client.putObject(PutObjectRequest.builder().bucket(bucketName).key(objectKey).build(),
                RequestBody.fromString(objectData));
        System.out.println("Object uploaded: " + objectKey);

        // 下载对象
        GetObjectResponse getObjectResponse = s3Client.getObject(GetObjectRequest.builder().bucket(bucketName).key(objectKey).build());
        String downloadedObjectData = getObjectResponse.readAllBytes().asUtf8String();
        System.out.println("Object downloaded: " + downloadedObjectData);

        // 删除对象
        s3Client.deleteObject(DeleteObjectRequest.builder().bucket(bucketName).key(objectKey).build());
        System.out.println("Object deleted: " + objectKey);

        // 删除存储桶
        s3Client.deleteBucket(DeleteBucketRequest.builder().bucket(bucketName).build());
        System.out.println("Bucket deleted: " + bucketName);
    }
}

上述代码展示了如何使用AWS SDK连接到AWS S3，并进行存储桶的创建、对象的上传、下载和删除等操作。请注意，您需要使用正确的AWS凭证和区域来初始化S3Client对象。