Question

I am familiar with AWS Java SDK, I also tried to browse the corresponding Javadoc, but I could not realize how do I create a sub directory, i.e., a directory object within a bucket, and how do I upload files to it.

Assume bucketName and dirName correspond to already existing bucket (with public permission) and a new (object) directory which needs to be created within the bucket (i.e. bucketName/dirName/)

I have tried the following:

AmazonS3Client s3 = new AmazonS3Client(
    new BasicAWSCredentials(ACCESS_KEY, SECRET_KEY));
s3.createBucket(bucketName + "/" + dirName); //throws exception

which throws an exception on the second line.

A short snippet which creates a sub-directory and uploads files to it will be deeply appreciated.

Answer 1

There are no “sub-directories” in S3. There are buckets and there are keys within buckets.

You can emulate traditional directories by using prefix searches. For example, you can store the following keys in a bucket:

foo/bar1
foo/bar2
foo/bar3
blah/baz1
blah/baz2

and then do a prefix search for foo/ and you will get back:

foo/bar1
foo/bar2
foo/bar3

See AmazonS3.listObjects for more details.

---

Update: Assuming you already have an existing bucket, the key under that bucket would contain the /:

s3.putObject("someBucket", "foo/bar1", file1);
s3.putObject("someBucket", "foo/bar2", file2);
...

Then you can list all keys starting with foo/:

ObjectListing listing = s3.listObjects("someBucket", "foo/");