How to upload file to folder using BlockBlobClient

I am using azure-storage-blob Java SDK version 12.8.0 with SpringBoot 2.x, and I would like to do multipart-uploads from local storage to Azure blob container, it worked well when specifying the filename only in the code.

Here's the sample code

String folder = "20241024T180025";
String filename = "corey.jpg";
String folderandfilename = folder + "/" + filename;
 
BlobContainerClient containerClient = new BlobContainerClientBuilder()
                    .connectionString(connectionString)
                    .containerName(containerName)
                    .buildClient();

BlockBlobClient blobClient = containerClient.getBlobClient(filename).getBlockBlobClient();
List<String> blockIds = new ArrayList<>();
try (BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream(file))) {
    byte[] buffer = new byte[(int) chunkSize];
    int bytesRead;
    int blockNumber = 0;
            
    while ((bytesRead = inputStream.read(buffer)) != -1) {
        String blockId = Base64.getEncoder().encodeToString(String.format("block-%07d", blockNumber).getBytes(StandardCharsets.UTF_8));
        byte[] uploadBuffer;
        if (bytesRead < buffer.length) {
            uploadBuffer = Arrays.copyOf(buffer, bytesRead);
        } else {
            uploadBuffer = buffer;
        }
                        
        blockIds.add(blockId);
        blobClient.stageBlock(blockId, new ByteArrayInputStream(uploadBuffer), bytesRead);
        blockNumber++;
    }
    blobClient.commitBlockList(blockIds);
}

I also need to create a folder for storing the uploaded file so I assigned the String folderandfilename to it.

BlockBlobClient blobClient = containerClient.getBlobClient(folderandfilename).getBlockBlobClient();

But it failed with error message:

Status code 400, "InvalidBlobOrBlockThe specified blob or block content is invalid.\n

It seems like BlockBlobClient accepts the filename like "corey.jpg" but doesn't support something like "20241024T180025/corey.jpg", is there anything I can do to fix the issue and achieve my goal?

I would appreciate any ideas, thanks.

How to upload file to folder using BlockBlobClient?

In Azure Blob storage the folders are virtual directories. so,"20241024T180025/corey.jpg" should be treated as a single blob name, not an actual directory structure.

You can use the below code to upload file to folder using BlockBlobClient using Azure java SDK.

Code:

String connectionString = "xxxxx";
        String containerName = "venkat";
        String folder = "20241024T180025";
        String filename = "corey.jpg";
        String folderandfilename = folder + "/" + filename;
        
        long chunkSize = 4 * 1024 * 1024; // 4MB chunk size, adjust if needed
        File file = new File("C:\image stamp.jpg");

        BlobContainerClient containerClient = new BlobContainerClientBuilder()
                .connectionString(connectionString)
                .containerName(containerName)
                .buildClient();
        BlockBlobClient blobClient = containerClient.getBlobClient(folderandfilename).getBlockBlobClient();
       
        List<String> blockIds = new ArrayList<>();

        try (BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream(file))) {
            byte[] buffer = new byte[(int) chunkSize];
            int bytesRead;
            int blockNumber = 0;

            while ((bytesRead = inputStream.read(buffer)) != -1) {
                String blockId = Base64.getEncoder().encodeToString(String.format("block-%07d", blockNumber).getBytes(StandardCharsets.UTF_8));
            
                byte[] uploadBuffer;
                if (bytesRead < buffer.length) {
                    uploadBuffer = Arrays.copyOf(buffer, bytesRead);
                } else {
                    uploadBuffer = buffer;
                }

                blockIds.add(blockId);
                blobClient.stageBlock(blockId, new ByteArrayInputStream(uploadBuffer), bytesRead);
                blockNumber++;
            }
            blobClient.commitBlockList(blockIds);
            System.out.println("File uploaded successfully as " + folderandfilename);

        } catch (IOException e) {
            e.printStackTrace();
        }

Output:

File uploaded successfully as 20241024T180025/corey.jpg

Portal: