Uploads & Downloads¶

JAWS provides upload and download support through the AWS S3 Transfer Manager, which handles multipart transfers and retries automatically.

Uploading Files¶

From S3.Dir¶

The S3.Dir interface includes an upload() method that uses the local file's name as the S3 key:

public interface Photos extends S3.Dir {
    // upload() is inherited from S3.Dir
}

Photos photos = bucket.as(Photos.class);
photos.upload(new File("/path/to/photo.jpg"));

With progress tracking¶

Pass a TransferListener to monitor upload progress:

photos.upload(new File("/path/to/large-video.mp4"), new TransferListener() {
    @Override
    public void transferInitiated(Context.TransferInitiated context) {
        System.out.println("Upload started");
    }

    @Override
    public void bytesTransferred(Context.BytesTransferred context) {
        System.out.println("Transferred: " + context.progressSnapshot().transferredBytes());
    }

    @Override
    public void transferComplete(Context.TransferComplete context) {
        System.out.println("Upload complete");
    }

    @Override
    public void transferFailed(Context.TransferFailed context) {
        System.err.println("Upload failed: " + context.exception().getMessage());
    }
});

From S3File¶

You can also upload directly to a specific S3File:

S3File target = bucket.root().file("path/to/destination.txt");
target.upload(new File("/path/to/source.txt"));

From S3Bucket¶

The bucket provides low-level upload methods:

// Upload a file
bucket.upload("path/to/key.txt", new File("/local/file.txt"));

// Upload from an input stream
bucket.upload("path/to/key.txt", inputStream, contentLength);

// Upload a string
bucket.putObject("path/to/key.txt", "file contents");

Downloading Files¶

From S3Bucket¶

FileDownload download = bucket.download("path/to/key.txt",
    new File("/local/destination.txt"));

// Wait for completion
download.completionFuture().join();

Writing Content¶

Through S3.File proxy¶

The S3.File interface provides methods for writing content directly:

public interface Config extends S3.File {}

Config config = root.config();
config.setValueAsString("{\"key\": \"value\"}");
config.setValueAsFile(new File("/path/to/config.json"));
config.setValueAsStream(inputStream);

Through S3File¶

S3File file = bucket.root().file("path/to/file.txt");
file.setValueAsString("content");
file.setValueAsFile(new File("/local/file.txt"));
file.setValueAsStream(inputStream);

Reading Content¶

Through S3.File proxy¶

Config config = root.config();
String content = config.getValueAsString();
InputStream stream = config.getValueAsStream();
long size = config.getSize();
String etag = config.getETag();
Instant modified = config.getLastModified();

Through S3File¶

S3File file = bucket.root().file("config.json");
String content = file.getValueAsString();
InputStream stream = file.getValueAsStream();