Fazer upload recursivo de um diretório local em um bucket do Amazon Simple Storage Service (Amazon S3)

Use um S3 TransferManager para carregar um diretório local. Veja o arquivo completo e teste.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import software.amazon.awssdk.services.s3.model.ObjectIdentifier;
import software.amazon.awssdk.transfer.s3.S3TransferManager;
import software.amazon.awssdk.transfer.s3.model.CompletedDirectoryUpload;
import software.amazon.awssdk.transfer.s3.model.DirectoryUpload;
import software.amazon.awssdk.transfer.s3.model.UploadDirectoryRequest;

import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.Paths;
import java.util.UUID;

    public Integer uploadDirectory(S3TransferManager transferManager,
            URI sourceDirectory, String bucketName) {
        DirectoryUpload directoryUpload = transferManager.uploadDirectory(UploadDirectoryRequest.builder()
                .source(Paths.get(sourceDirectory))
                .bucket(bucketName)
                .build());

        CompletedDirectoryUpload completedDirectoryUpload = directoryUpload.completionFuture().join();
        completedDirectoryUpload.failedTransfers()
                .forEach(fail -> logger.warn("Object [{}] failed to transfer", fail.toString()));
        return completedDirectoryUpload.failedTransfers().size();
    }