Azure Storage Blob Java

MicrosoftOfficialCreated by Microsoft

Skill
Tool integration
Cloud and DevOps
MIT
No issues found

From the author

Build blob storage applications with Azure Storage Blob SDK for Java. Use when uploading, downloading, or managing files in Azure Blob Storage, working with containers, or implementing streaming data operations.

— the description by Microsoft

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured reference for developers to interact with Azure Blob Storage using the com.azure:azure-storage-blob Java SDK. It covers the full lifecycle of blob operations, including client initialization, container management, data streaming, metadata handling, and security via SAS tokens or Entra ID credentials. The documentation includes practical patterns for uploading and downloading data, managing blob properties, and handling storage-specific exceptions.

What it does

Initializes service, container, and blob clients with various authentication methods.
Facilitates file uploads and downloads using streams, files, or binary data.
Manages blob containers, including creation, listing, and deletion.
Configures blob metadata, HTTP headers, and lease management for concurrency.
Generates SAS tokens for secure, time-limited access to resources.
Implements error handling for common storage-related exceptions.

When to use it

When building Java applications that require cloud-based file storage.
When implementing streaming data pipelines to or from Azure storage.
When needing to manage blob access permissions via SAS tokens.
When integrating Azure storage into existing Java enterprise workflows.

Advantages

Provides standardized patterns for secure authentication using DefaultAzureCredential.
Supports flexible data transfer methods including streams and direct file uploads.
Includes robust error handling patterns for storage-specific status codes.
Offers granular control over blob properties, metadata, and concurrency via leases.

Usage examples

“How do I upload a local file to Azure Blob Storage using Java?”: The agent provides the code to initialize a BlobClient and use the uploadFromFile method, including optional overwrite parameters.
“Show me how to list blobs in a specific container with a prefix.”: The agent demonstrates using ListBlobsOptions with a prefix to filter results, returning a list of BlobItem objects.
“How can I authenticate my Java app to Azure Storage?”: The agent explains how to use DefaultAzureCredentialBuilder for secure production access or how to use connection strings for simpler setups.
“Generate a SAS token for a blob in Java.”: The agent provides the code to create a BlobSasPermission object and use the generateSas method on a BlobClient.

Install

Download the skill as a ZIP:
https://autogineer.com/agent-skills/microsoft/azure-storage-blob-java/download

Unzip it into the cross-client skills folder of your project:

mkdir -p .agents/skills && unzip azure-storage-blob-java.zip -d .agents/skills

Documentation by Microsoft

Azure Storage Blob SDK for Java

Build blob storage applications using the Azure Storage Blob SDK for Java.

Installation

<dependency>
    <groupId>com.azure</groupId>
    <artifactId>azure-storage-blob</artifactId>
    <version>12.33.0</version>
</dependency>

Client Creation

BlobServiceClient

import com.azure.storage.blob.BlobServiceClient;
import com.azure.storage.blob.BlobServiceClientBuilder;

// With SAS token
BlobServiceClient serviceClient = new BlobServiceClientBuilder()
    .endpoint("<storage-account-url>")
    .sasToken("<sas-token>")
    .buildClient();

// With connection string
BlobServiceClient serviceClient = new BlobServiceClientBuilder()
    .connectionString("<connection-string>")
    .buildClient();

With DefaultAzureCredential

import com.azure.core.credential.TokenCredential;
import com.azure.identity.AzureIdentityEnvVars;
import com.azure.identity.DefaultAzureCredentialBuilder;
import com.azure.identity.ManagedIdentityCredentialBuilder;

// Local dev: DefaultAzureCredential. Production: set AZURE_TOKEN_CREDENTIALS=prod or AZURE_TOKEN_CREDENTIALS=<specific_credential>
TokenCredential credential = new DefaultAzureCredentialBuilder()
    .requireEnvVars(AzureIdentityEnvVars.AZURE_TOKEN_CREDENTIALS)
    .build();
// Or use a specific credential directly in production:
// See https://learn.microsoft.com/java/api/overview/azure/identity-readme?view=azure-java-stable#credential-classes
// TokenCredential credential = new ManagedIdentityCredentialBuilder().build();

BlobServiceClient serviceClient = new BlobServiceClientBuilder()
    .endpoint("<storage-account-url>")
    .credential(credential)
    .buildClient();

BlobContainerClient

import com.azure.storage.blob.BlobContainerClient;

// From service client
BlobContainerClient containerClient = serviceClient.getBlobContainerClient("mycontainer");

// Direct construction
BlobContainerClient containerClient = new BlobContainerClientBuilder()
    .connectionString("<connection-string>")
    .containerName("mycontainer")
    .buildClient();

BlobClient

import com.azure.storage.blob.BlobClient;

// From container client
BlobClient blobClient = containerClient.getBlobClient("myblob.txt");

// With directory structure
BlobClient blobClient = containerClient.getBlobClient("folder/subfolder/myblob.txt");

// Direct construction
BlobClient blobClient = new BlobClientBuilder()
    .connectionString("<connection-string>")
    .containerName("mycontainer")
    .blobName("myblob.txt")
    .buildClient();

Core Patterns

Create Container

// Create container
serviceClient.createBlobContainer("mycontainer");

// Create if not exists
BlobContainerClient container = serviceClient.createBlobContainerIfNotExists("mycontainer");

// From container client
containerClient.create();
containerClient.createIfNotExists();

Upload Data

import com.azure.core.util.BinaryData;

// Upload string
String data = "Hello, Azure Blob Storage!";
blobClient.upload(BinaryData.fromString(data));

// Upload with overwrite
blobClient.upload(BinaryData.fromString(data), true);

Upload from File

blobClient.uploadFromFile("local-file.txt");

// With overwrite
blobClient.uploadFromFile("local-file.txt", true);

Upload from Stream

import com.azure.storage.blob.specialized.BlockBlobClient;

BlockBlobClient blockBlobClient = blobClient.getBlockBlobClient();

try (ByteArrayInputStream dataStream = new ByteArrayInputStream(data.getBytes())) {
    blockBlobClient.upload(dataStream, data.length());
}

Upload with Options

import com.azure.storage.blob.models.BlobHttpHeaders;
import com.azure.storage.blob.options.BlobParallelUploadOptions;

BlobHttpHeaders headers = new BlobHttpHeaders()
    .setContentType("text/plain")
    .setCacheControl("max-age=3600");

Map<String, String> metadata = Map.of("author", "john", "version", "1.0");

try (InputStream stream = new FileInputStream("large-file.bin")) {
    BlobParallelUploadOptions options = new BlobParallelUploadOptions(stream)
        .setHeaders(headers)
        .setMetadata(metadata);
    
    blobClient.uploadWithResponse(options, null, Context.NONE);
}

Upload if Not Exists

import com.azure.storage.blob.models.BlobRequestConditions;

BlobParallelUploadOptions options = new BlobParallelUploadOptions(inputStream, length)
    .setRequestConditions(new BlobRequestConditions().setIfNoneMatch("*"));

blobClient.uploadWithResponse(options, null, Context.NONE);

Download Data

// Download to BinaryData
BinaryData content = blobClient.downloadContent();
String text = content.toString();

// Download to file
blobClient.downloadToFile("downloaded-file.txt");

Download to Stream

try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {
    blobClient.downloadStream(outputStream);
    byte[] data = outputStream.toByteArray();
}

Download with InputStream

import com.azure.storage.blob.specialized.BlobInputStream;

try (BlobInputStream blobIS = blobClient.openInputStream()) {
    byte[] buffer = new byte[1024];
    int bytesRead;
    while ((bytesRead = blobIS.read(buffer)) != -1) {
        // Process buffer
    }
}

Upload via OutputStream

import com.azure.storage.blob.specialized.BlobOutputStream;

try (BlobOutputStream blobOS = blobClient.getBlockBlobClient().getBlobOutputStream()) {
    blobOS.write("Data to upload".getBytes());
}

List Blobs

import com.azure.storage.blob.models.BlobItem;

// List all blobs
for (BlobItem blobItem : containerClient.listBlobs()) {
    System.out.println("Blob: " + blobItem.getName());
}

// List with prefix (virtual directory)
import com.azure.storage.blob.models.ListBlobsOptions;

ListBlobsOptions options = new ListBlobsOptions().setPrefix("folder/");
for (BlobItem blobItem : containerClient.listBlobs(options, null)) {
    System.out.println("Blob: " + blobItem.getName());
}

List Blobs by Hierarchy

import com.azure.storage.blob.models.BlobListDetails;

String delimiter = "/";
ListBlobsOptions options = new ListBlobsOptions()
    .setPrefix("data/")
    .setDetails(new BlobListDetails().setRetrieveMetadata(true));

for (BlobItem item : containerClient.listBlobsByHierarchy(delimiter, options, null)) {
    if (item.isPrefix()) {
        System.out.println("Directory: " + item.getName());
    } else {
        System.out.println("Blob: " + item.getName());
    }
}

Delete Blob

blobClient.delete();

// Delete if exists
blobClient.deleteIfExists();

// Delete with snapshots
import com.azure.storage.blob.models.DeleteSnapshotsOptionType;
blobClient.deleteWithResponse(DeleteSnapshotsOptionType.INCLUDE, null, null, Context.NONE);

Copy Blob

import com.azure.storage.blob.models.BlobCopyInfo;
import com.azure.core.util.polling.SyncPoller;

// Async copy (for large blobs or cross-account)
SyncPoller<BlobCopyInfo, Void> poller = blobClient.beginCopy("<source-blob-url>", Duration.ofSeconds(1));
poller.waitForCompletion();

// Sync copy from URL (for same account)
blobClient.copyFromUrl("<source-blob-url>");

Generate SAS Token

import com.azure.storage.blob.sas.*;
import java.time.OffsetDateTime;

// Blob-level SAS
BlobSasPermission permissions = new BlobSasPermission().setReadPermission(true);
OffsetDateTime expiry = OffsetDateTime.now().plusDays(1);

BlobServiceSasSignatureValues sasValues = new BlobServiceSasSignatureValues(expiry, permissions);
String sasToken = blobClient.generateSas(sasValues);

// Container-level SAS
BlobContainerSasPermission containerPermissions = new BlobContainerSasPermission()
    .setReadPermission(true)
    .setListPermission(true);
    
BlobServiceSasSignatureValues containerSasValues = new BlobServiceSasSignatureValues(expiry, containerPermissions);
String containerSas = containerClient.generateSas(containerSasValues);

Blob Properties and Metadata

import com.azure.storage.blob.models.BlobProperties;

// Get properties
BlobProperties properties = blobClient.getProperties();
System.out.println("Size: " + properties.getBlobSize());
System.out.println("Content-Type: " + properties.getContentType());
System.out.println("Last Modified: " + properties.getLastModified());

// Set metadata
Map<String, String> metadata = Map.of("key1", "value1", "key2", "value2");
blobClient.setMetadata(metadata);

// Set HTTP headers
BlobHttpHeaders headers = new BlobHttpHeaders()
    .setContentType("application/json")
    .setCacheControl("max-age=86400");
blobClient.setHttpHeaders(headers);

Lease Blob

import com.azure.storage.blob.specialized.BlobLeaseClient;
import com.azure.storage.blob.specialized.BlobLeaseClientBuilder;

BlobLeaseClient leaseClient = new BlobLeaseClientBuilder()
    .blobClient(blobClient)
    .buildClient();

// Acquire lease (-1 for infinite)
String leaseId = leaseClient.acquireLease(60);

// Renew lease
leaseClient.renewLease();

// Release lease
leaseClient.releaseLease();

Error Handling

import com.azure.storage.blob.models.BlobStorageException;

try {
    blobClient.download(outputStream);
} catch (BlobStorageException e) {
    System.out.println("Status: " + e.getStatusCode());
    System.out.println("Error code: " + e.getErrorCode());
    // 404 = Blob not found
    // 409 = Conflict (lease, etc.)
}

Proxy Configuration

import com.azure.core.http.ProxyOptions;
import com.azure.core.http.netty.NettyAsyncHttpClientBuilder;
import java.net.InetSocketAddress;

ProxyOptions proxyOptions = new ProxyOptions(
    ProxyOptions.Type.HTTP,
    new InetSocketAddress("localhost", 8888));

BlobServiceClient client = new BlobServiceClientBuilder()
    .endpoint("<endpoint>")
    .sasToken("<sas-token>")
    .httpClient(new NettyAsyncHttpClientBuilder().proxy(proxyOptions).build())
    .buildClient();

Environment Variables

AZURE_STORAGE_CONNECTION_STRING=DefaultEndpointsProtocol=https;AccountName=...  # Alternative to Entra ID auth
AZURE_STORAGE_ACCOUNT_URL=https://<account>.blob.core.windows.net  # Required for all auth methods
AZURE_TOKEN_CREDENTIALS=prod  # Required only if DefaultAzureCredential is used in production

Trigger Phrases

"Azure Blob Storage Java"
"upload download blob"
"blob container SDK"
"storage streaming"
"SAS token generation"
"blob metadata properties"

Files

ATTRIBUTION.mdAdded by AutoGineer976 B
LICENSELicence file added by AutoGineer1.1 KiB
SKILL.md10.6 KiB
references/examples.md11.3 KiB

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Security

No issues found by our static scan· No issues found

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Created by

Microsoft

Publisher

Microsoft (Official)

Source

microsoft/skills · .github/plugins/azure-sdk-java/skills/azure-storage-blob-java · commit 0696600

Licence

MIT License (redistribution allowed)

LICENSE (added by AutoGineer from LICENSE)
ATTRIBUTION.md (written by AutoGineer)

Synced

2026-11-09

AutoGineer is not affiliated with or endorsed by Microsoft or Microsoft.

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The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download azure-storage-blob-java.zip