使用 Java sdk 删除 aws s3 存储桶中的文件夹

Question

I have a question, how could I do to delete a folder/directory when calling a delete method?

for example I have those folders with files inside:

So, I have this method that removes everything inside the directory and leaves it empty...

public void deleteFilesFromS3Bucket(Object object) {
        try {
            String objectName = object.getClass().getSimpleName();
            Field privateObjectId = object.getClass().getDeclaredField("id");
            privateObjectId.setAccessible(true);
            Long objectId = (Long) privateObjectId.get(object);
            for(S3ObjectSummary file : s3.listObjects(bucketName, objectName + "-" + objectId).getObjectSummaries()) {
                s3.deleteObject(bucketName, file.getKey());
            }
        } catch (SdkClientException | NoSuchFieldException | IllegalAccessException e) {
            e.getMessage();
        }
    }

But I want to know if there is any way that deleting will remove the directory/folder...

Answer 1

Folders do not actually exist in Amazon S3.

For example, you could copy a file to: s3://bucket-name/News-9/foo.txt

This would cause the News-9 directory to magically appear. Then, if the object was deleted, the directory will magically disappear.

However, if a Folder is created using the Create Folder button in the S3 management console, a zero-length object is created with the name of the Folder . This forces the directory to appear even if there are no objects in the directory (because there is an object there).

Therefore, if a folder/directory appears in S3 with no objects inside it, there is actually a zero-length object with the name of that folder. It can be delete with a normal DeleteObject() call. This will cause the folder to disappear.