This article shows how to set or change the access tier for a block blob using theAzure Storage client library for Java.

Prerequisites

• Azure subscription -create one for free
• Azure storage account -create a storage account
• Java Development Kit (JDK) version 8 or later (we recommend version 17 for the best experience)
• Apache Maven is used for project management in this example

Set up your environment

If you don't have an existing project, this section shows you how to set up a project to work with the Azure Blob Storage client library for Java. For more information, seeGet started with Azure Blob Storage and Java.

To work with the code examples in this article, follow these steps to set up your project.

Install packages

Open thepom.xml file in your text editor. Install the packages byincluding the BOM file, orincluding a direct dependency.

Add import statements

Add the followingimport statements:

import com.azure.core.util.polling.LongRunningOperationStatus;import com.azure.core.util.polling.PollResponse;import com.azure.core.util.polling.SyncPoller;import com.azure.storage.blob.*;import com.azure.storage.blob.models.*;import com.azure.storage.blob.options.BlobBeginCopyOptions;

Authorization

The authorization mechanism must have the necessary permissions to set a blob's access tier. For authorization with Microsoft Entra ID (recommended), you need Azure RBAC built-in roleStorage Blob Data Contributor or higher. To learn more, see the authorization guidance forSet Blob Tier.

Create a client object

To connect an app to Blob Storage, create an instance ofBlobServiceClient.

The following example usesBlobServiceClientBuilder to build aBlobServiceClient object usingDefaultAzureCredential, and shows how to create container and blob clients, if needed:

// Azure SDK client builders accept the credential as a parameter// TODO: Replace <storage-account-name> with your actual storage account nameBlobServiceClient blobServiceClient = new BlobServiceClientBuilder()        .endpoint("https://<storage-account-name>.blob.core.windows.net/")        .credential(new DefaultAzureCredentialBuilder().build())        .buildClient();// If needed, you can create a BlobContainerClient object from the BlobServiceClientBlobContainerClient containerClient = blobServiceClient        .getBlobContainerClient("<container-name>");// If needed, you can create a BlobClient object from the BlobContainerClientBlobClient blobClient = containerClient        .getBlobClient("<blob-name>");

To learn more about creating and managing client objects, seeCreate and manage client objects that interact with data resources.

About block blob access tiers

To manage costs for storage needs, it can be helpful to organize your data based on how frequently it's accessed and how long it needs to be retained. Azure storage offers different access tiers so that you can store your blob data in the most cost-effective manner based on how it's being used.

Access tiers for blob data

Azure Storage access tiers include:

• Hot tier - An online tier optimized for storing data that is accessed or modified frequently. The hot tier has the highest storage costs, but the lowest access costs.
• Cool tier - An online tier optimized for storing data that is infrequently accessed or modified. Data in the cool tier should be stored for a minimum of 30 days. The cool tier has lower storage costs and higher access costs compared to the hot tier.
• Cold tier - An online tier optimized for storing data that is infrequently accessed or modified. Data in the cold tier should be stored for a minimum of 90 days. The cold tier has lower storage costs and higher access costs compared to the cool tier.
• Archive tier - An offline tier optimized for storing data that is rarely accessed, and that has flexible latency requirements, on the order of hours. Data in the archive tier should be stored for a minimum of 180 days.

To learn more about access tiers, seeAccess tiers for blob data.

While a blob is in the Archive access tier, it's considered to be offline, and can't be read or modified. In order to read or modify data in an archived blob, you must first rehydrate the blob to an online tier. To learn more about rehydrating a blob from the Archive tier to an online tier, seeBlob rehydration from the Archive tier.

Restrictions

Setting the access tier is only allowed on block blobs. To learn more about restrictions on setting a block blob's access tier, seeSet Blob Tier (REST API).

Set a blob's access tier during upload

You can set a blob's access tier on upload by using theBlobUploadFromFileOptions class. The following code example shows how to set the access tier when uploading a blob:

public void uploadBlobWithAccessTier(BlobContainerClient blobContainerClient, Path filePath) {    String fileName = filePath.getFileName().toString();    BlobClient blobClient = blobContainerClient.getBlobClient(fileName);    BlobUploadFromFileOptions options = new BlobUploadFromFileOptions(filePath.toString())            .setTier(AccessTier.COOL);    try {        Response<BlockBlobItem> blockBlob = blobClient.uploadFromFileWithResponse(options, null, null);    } catch (UncheckedIOException ex) {        System.err.printf("Failed to upload from file: %s%n", ex.getMessage());    }}

To learn more about uploading a blob with Java, seeUpload a blob with Java.

Change the access tier for an existing block blob

You can change the access tier of an existing block blob by using one of the following methods:

• setAccessTier
• setAccessTierWithResponse

The following code example shows how to change the access tier to Cool for an existing blob:

public void changeBlobAccessTier(BlobClient blobClient) {    // Change the blob's access tier to cool    blobClient.setAccessTier(AccessTier.COOL);}

If you're rehydrating an archived blob, use thesetAccessTierWithResponse method. Set thetier parameter to a validAccessTier value ofHOT,COOL,COLD, orARCHIVE. You can optionally set thepriority parameter to a validRehydratePriority valueHIGH orSTANDARD.

The following code example shows how to rehydrate an archived blob by changing the access tier to Hot:

public void rehydrateBlobSetAccessTier(BlobClient blobClient) {    // Rehydrate the blob to hot tier using a standard rehydrate priority    blobClient.setAccessTierWithResponse(        AccessTier.HOT,        RehydratePriority.STANDARD,        null,         null,         null);}

ThesetAccessTierWithResponse method can also accept aBlobSetAccessTierOptions parameter to specify configuration options.

Copy a blob to a different access tier

You can change the access tier of an existing block blob by specifying an access tier as part of a copy operation. To change the access tier during a copy operation, use theBlobBeginCopyOptions class.

You can use thesetTier method to specify theAccessTier value asHOT,COOL,COLD, orARCHIVE. If you're rehydrating a blob from the archive tier using a copy operation, use thesetRehydratePriority method to specify theRehydratePriority value asHIGH orSTANDARD.

The following code example shows how to rehydrate an archived blob to the Hot tier using a copy operation:

public void rehydrateBlobUsingCopy(    BlobClient sourceArchiveBlob,    BlobClient destinationRehydratedBlob) {    // Note: the destination blob must have a different name than the archived source blob    // Start the copy operation and wait for it to complete    final SyncPoller<BlobCopyInfo, Void> poller = destinationRehydratedBlob.beginCopy(            new BlobBeginCopyOptions(sourceArchiveBlob.getBlobUrl())                    .setTier(AccessTier.HOT)                    .setRehydratePriority(RehydratePriority.STANDARD));                        PollResponse<BlobCopyInfo> response = poller            .waitUntil(LongRunningOperationStatus.SUCCESSFULLY_COMPLETED);}

To learn more about copying a blob with Java, seeCopy a blob with Java.

Resources

To learn more about setting access tiers using the Azure Blob Storage client library for Java, see the following resources.

Code samples

• View code samples from this article (GitHub)

REST API operations

The Azure SDK for Java contains libraries that build on top of the Azure REST API, allowing you to interact with REST API operations through familiar Java paradigms. The client library methods for setting access tiers use the following REST API operation:

• Set Blob Tier (REST API)

Client library resources

• Client library reference documentation
• Client library source code
• Package (Maven)

See also

• Access tiers best practices
• Blob rehydration from the archive tier

Related content

• This article is part of the Blob Storage developer guide for Java. To learn more, see the full list of developer guide articles atBuild your Java app.