Does the SDK Support Uploading, Downloading, or Copying Objects in a Batch?

No.

Currently, the SDK does not provide such APIs. You need to encapsulate the service codes for uploading, downloading, or copying objects in a batch by yourself. The procedure is as follows:

1. Invoke listObjects to list all objects to be uploaded, downloaded, or copied. For details about the code example, see Listing Objects.
2. Invokes the API for uploading, downloading, or copying a single object for the listed objects.

The example code for uploading objects in a batch is as follows:

// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables ACCESS_KEY_ID and SECRET_ACCESS_KEY_ID.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/eu/usermanual-ca/ca_01_0003.html.
String ak = System.getenv("ACCESS_KEY_ID");
String sk = System.getenv("SECRET_ACCESS_KEY_ID");
String endPoint = "https://your-endpoint";
// Define the prefix of objects in a bucket.
final String objectPre = "object/";
// Folder to be uploaded. An example of the folder path is /storage/emulated/0/Pictures. Ensure that the files to be uploaded in the folder meet expectations.
// Example of obtaining the path: final String localDirPath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/Picture";
final String localDirPath = Environment.getExternalStorageDirectory().getAbsolutePath() + "localDirPath";

final List<File> list = new ArrayList<>();

public void uploadFiles() {
// Traverse the folder to be uploaded and obtain all objects to be uploaded.
	File file = new File(localDirPath);
	listFiles(file);

// Create an ObsClient instance.
	final ObsClient obsClient = new ObsClient(ak, sk, endPoint);

// Initialize the thread pool.
	ExecutorService executorService = Executors.newFixedThreadPool(20);

// Concurrently upload parts.
	for (File f : list) {
		executorService.execute(() -> {
			if (f.isDirectory()) {
            // For empty folders, create empty folder objects in the bucket.
				String remoteObjectKey = objectPre + f.getPath().substring(localDirPath.length() + 1) + "/";
				obsClient.putObject(bucketName, remoteObjectKey, new ByteArrayInputStream(new byte[0]));
			} else {
				String remoteObjectKey = objectPre + f.getPath().substring(localDirPath.length() + 1);
				obsClient.putObject(bucketName, remoteObjectKey, new File(f.getPath()));
			}
		});
	}

// Wait until the upload is complete.
	executorService.shutdown();
	while (!executorService.isTerminated()) {
		try {
			executorService.awaitTermination(5, TimeUnit.SECONDS);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
// Close obsClient.
	try {
		obsClient.close();
	} catch (IOException e) {
		e.printStackTrace();
	}
}

// Scan all objects in the folder.
void listFiles(File file) {
	File[] fs = file.listFiles();
	assert fs != null;
	if (fs.length < 1) {
        // If uploading an empty folder is required, add it to the list.
		list.add(file);
	} else {
		for (File f : fs) {
			if (f.isDirectory()) {
				listFiles(f);
			}
			if (f.isFile()) {
                // Add objects to be uploaded to the list.
				list.add(f);
			}
		}
	}
}

You can use multiple threads to concurrently upload, download, and copy data to improve efficiency.