Amazon Web Services (AWS) S3 Java create a sub directory (object)

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.

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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/"); 

Answer 2

S3 doesn't see directories in the traditional way we do this on our operating systems. Here is how you can create a directory:

public static void createFolder(String bucketName, String folderName, AmazonS3 client) {     // create meta-data for your folder and set content-length to 0     ObjectMetadata metadata = new ObjectMetadata();     metadata.setContentLength(0);      // create empty content     InputStream emptyContent = new ByteArrayInputStream(new byte[0]);      // create a PutObjectRequest passing the folder name suffixed by /     PutObjectRequest putObjectRequest = new PutObjectRequest(bucketName,                 folderName + SUFFIX, emptyContent, metadata);      // send request to S3 to create folder     client.putObject(putObjectRequest); } 

As casablanca already said you can upload files to directories like this:

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

Read the whole tutorial here for details, and the most important thing is you will find info how to delete the directories.