Azure blob container listBlobs to fetch files with a specific extension in java

Question

I've a java code where I list blobs and filter in for loop to fetch only files with a specific extension. Is there a way to query/request container to return just blobs with specific extension? I don't want to loop through all the blobs in the container to do this.

score 4 · Answer 1 · answered Apr 08 '19 at 17:05

Is there a way to query/request container to return just blobs with specific extension?

Unfortunately no. You can't query blob storage to return blobs with a particular extension.

I don't want to loop through all the blobs in the container to do this.

If you're using Storage REST API, that's the only way to do it. You will need to list blobs in the container and then loop through the blobs and do the filtering based on extension (or any other criteria) on the client side.

Possible Solution

One possible solution would be to use Azure Search Service and have your blob metadata indexed there. Then you should be able to search for a particular extension and get the list of blobs.

score 2 · Answer 2 · answered Jan 25 '21 at 22:48

2

You can use ListBlobsOptions() with setPrefix to filter based on prefix as shown below

ListBlobsOptions options=new ListBlobsOptions();
options.setPrefix("<<prefix>>");
Duration fromDays = Duration.of(10, ChronoUnit.MINUTES);
BlobContainerClient containerClient = blobServiceClient.getBlobContainerClient("containerName");
for (BlobItem blobItem : containerClient.listBlobs(options,fromDays)) {
            System.out.println("\t" + blobItem.getName());
}

answered Jan 25 '21 at 22:48

Nitin

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The last parameter to **listBlobs**l is timeout and not **lfromDays **l ``` public PagedIterable listBlobs(ListBlobsOptions options, Duration timeout) { return this.listBlobs(options, null, timeout); } ``` – craftsmannadeem Nov 08 '22 at 12:07

score -1 · Answer 3 · answered Mar 10 '20 at 19:50

This is all you need

BlobContainer.ListBlobs(prefix, useFlatBlobListing: true, blobListingDetails: BlobListingDetails.None)
.OfType<CloudBlockBlob>()
.Where(x=> x.Name.EndsWith(".json"));

The prefix is just a partial path where search. The result is an IEnumerable<CloudBlockBlob>.

Azure blob container listBlobs to fetch files with a specific extension in java

3 Answers3