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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.

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Azure Storage Blob Java SDK - Examples

Comprehensive code examples for the Azure Storage Blob SDK for Java.

Table of Contents

Maven Dependency

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

Or use the BOM:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.azure</groupId>
            <artifactId>azure-sdk-bom</artifactId>
            <version>{bom_version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

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

Client Creation

Using Shared Key Credential

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

StorageSharedKeyCredential credential = new StorageSharedKeyCredential(accountName, accountKey);

String endpoint = String.format("https://%s.blob.core.windows.net", accountName);
BlobServiceClient blobServiceClient = new BlobServiceClientBuilder()
    .endpoint(endpoint)
    .credential(credential)
    .buildClient();

Using SAS Token

// Separate endpoint and SAS token
BlobServiceClient blobServiceClient = new BlobServiceClientBuilder()
    .endpoint("<your-storage-account-url>")
    .sasToken("<your-sasToken>")
    .buildClient();

// Combined URL with SAS token
BlobServiceClient blobServiceClient = new BlobServiceClientBuilder()
    .endpoint("<your-storage-account-url>" + "?" + "<your-sasToken>")
    .buildClient();

Using DefaultAzureCredential (Recommended)

import com.azure.identity.DefaultAzureCredentialBuilder;

BlobServiceClient blobServiceClient = new BlobServiceClientBuilder()
    .endpoint("<your-storage-account-url>")
    .credential(new DefaultAzureCredentialBuilder().build())
    .buildClient();

Container Operations

Create BlobContainerClient

import com.azure.storage.blob.BlobContainerClient;
import com.azure.storage.blob.BlobContainerClientBuilder;

// From BlobServiceClient
BlobContainerClient containerClient = blobServiceClient.getBlobContainerClient("mycontainer");

// From builder with SAS token
BlobContainerClient containerClient = new BlobContainerClientBuilder()
    .endpoint("<your-storage-account-url>")
    .sasToken("<your-sasToken>")
    .containerName("mycontainer")
    .buildClient();

Create Container

import java.util.Collections;
import java.util.Map;

// Simple create
containerClient.create();

// Create with metadata
Map<String, String> metadata = Collections.singletonMap("mykey", "myvalue");
containerClient.createWithResponse(metadata, null, null, Context.NONE);

// Create from service client
blobServiceClient.createBlobContainer("mycontainer");

List and Delete Containers

// List all containers
blobServiceClient.listBlobContainers().forEach(containerItem -> {
    System.out.println("Container name: " + containerItem.getName());
});

// Delete container
containerClient.delete();

Upload Blobs

Upload BinaryData

import com.azure.core.util.BinaryData;
import com.azure.storage.blob.BlobClient;

BlobClient blobClient = containerClient.getBlobClient("myblob");
String dataSample = "samples";
blobClient.upload(BinaryData.fromString(dataSample));

Upload from InputStream

import com.azure.storage.blob.specialized.BlockBlobClient;
import java.io.ByteArrayInputStream;

BlockBlobClient blockBlobClient = containerClient.getBlobClient("myblockblob").getBlockBlobClient();
String dataSample = "samples";
try (ByteArrayInputStream dataStream = new ByteArrayInputStream(dataSample.getBytes())) {
    blockBlobClient.upload(dataStream, dataSample.length());
}

Upload from File

BlobClient blobClient = containerClient.getBlobClient("myblockblob");
blobClient.uploadFromFile("local-file.jpg");

Upload with Overwrite Control

// Upload without overwrite (fails if blob exists)
blobClient.upload(BinaryData.fromString("data"), false);

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

// Upload with access conditions (fail if blob exists)
import com.azure.storage.blob.models.BlobRequestConditions;
import com.azure.storage.blob.options.BlobParallelUploadOptions;

BlobParallelUploadOptions options = new BlobParallelUploadOptions(dataStream, dataSample.length());
options.setRequestConditions(new BlobRequestConditions().setIfNoneMatch("*"));
blobClient.uploadWithResponse(options, null, Context.NONE);

Upload with Metadata and Headers

import com.azure.storage.blob.models.BlobHttpHeaders;
import java.security.MessageDigest;
import java.nio.charset.StandardCharsets;

Map<String, String> metadata = Collections.singletonMap("myblobmetadata", "sample");
BlobHttpHeaders headers = new BlobHttpHeaders()
    .setContentDisposition("attachment")
    .setContentType("text/html; charset=utf-8");

String data = "Hello world!";
byte[] md5 = MessageDigest.getInstance("MD5").digest(data.getBytes(StandardCharsets.UTF_8));

try (InputStream dataStream = new ByteArrayInputStream(data.getBytes(StandardCharsets.UTF_8))) {
    blockBlobClient.uploadWithResponse(
        dataStream, 
        data.length(), 
        headers, 
        metadata, 
        null,  // tier
        md5,   // content MD5
        null,  // request conditions
        null,  // timeout
        null   // context
    );
}

Download Blobs

Download to BinaryData

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

Download to OutputStream

import java.io.ByteArrayOutputStream;

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

Download to File

blobClient.downloadToFile("downloaded-file.jpg");

Download via InputStream

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

try (BlobInputStream blobIS = blobClient.openInputStream()) {
    int data = blobIS.read();
    // Process data...
}

List Blobs

Simple Listing

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

for (BlobItem blobItem : containerClient.listBlobs()) {
    System.out.println("Blob name: " + blobItem.getName());
}

List and Create Clients

for (BlobItem blobItem : containerClient.listBlobs()) {
    BlobClient blobClient;
    if (blobItem.getSnapshot() != null) {
        blobClient = containerClient.getBlobClient(blobItem.getName(), blobItem.getSnapshot());
    } else {
        blobClient = containerClient.getBlobClient(blobItem.getName());
    }
    System.out.println("Blob URI: " + blobClient.getBlobUrl());
}

SAS Token Generation

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

// Generate Account SAS
OffsetDateTime expiryTime = OffsetDateTime.now().plusDays(1);
AccountSasPermission accountSasPermission = new AccountSasPermission().setReadPermission(true);
AccountSasService services = new AccountSasService().setBlobAccess(true);
AccountSasResourceType resourceTypes = new AccountSasResourceType().setObject(true);

AccountSasSignatureValues accountSasValues = new AccountSasSignatureValues(
    expiryTime, accountSasPermission, services, resourceTypes);
String sasToken = blobServiceClient.generateAccountSas(accountSasValues);

// Generate Container SAS
BlobContainerSasPermission containerSasPermission = new BlobContainerSasPermission().setCreatePermission(true);
BlobServiceSasSignatureValues serviceSasValues = new BlobServiceSasSignatureValues(expiryTime, containerSasPermission);
String containerSas = containerClient.generateSas(serviceSasValues);

// Generate Blob SAS
BlobSasPermission blobSasPermission = new BlobSasPermission().setReadPermission(true);
BlobServiceSasSignatureValues blobSasValues = new BlobServiceSasSignatureValues(expiryTime, blobSasPermission);
String blobSas = blobClient.generateSas(blobSasValues);

Error Handling

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

try {
    containerClient.create();
} catch (BlobStorageException e) {
    if (e.getErrorCode() == BlobErrorCode.CONTAINER_ALREADY_EXISTS) {
        System.out.println("Container already exists: " + containerClient.getBlobContainerUrl());
    } else if (e.getErrorCode() == BlobErrorCode.CONTAINER_BEING_DELETED) {
        System.out.println("Container is being deleted: " + e.getServiceMessage());
    } else if (e.getErrorCode() == BlobErrorCode.RESOURCE_NOT_FOUND) {
        System.out.println("Resource not found, status: " + e.getStatusCode());
    } else {
        throw e;
    }
}

Complete Working Example

import com.azure.storage.blob.*;
import com.azure.storage.blob.specialized.BlockBlobClient;
import com.azure.storage.common.StorageSharedKeyCredential;

import java.io.*;
import java.nio.charset.StandardCharsets;
import java.util.Locale;

public class BasicExample {

    public static void main(String[] args) throws IOException {
        String accountName = System.getenv("AZURE_STORAGE_ACCOUNT_NAME");
        String accountKey = System.getenv("AZURE_STORAGE_ACCOUNT_KEY");

        StorageSharedKeyCredential credential = new StorageSharedKeyCredential(accountName, accountKey);
        String endpoint = String.format(Locale.ROOT, "https://%s.blob.core.windows.net", accountName);

        BlobServiceClient storageClient = new BlobServiceClientBuilder()
            .endpoint(endpoint)
            .credential(credential)
            .buildClient();

        // Create container (names must be lowercase)
        BlobContainerClient containerClient = storageClient
            .getBlobContainerClient("myjavacontainer" + System.currentTimeMillis());
        containerClient.create();

        // Create blob client
        BlockBlobClient blobClient = containerClient
            .getBlobClient("HelloWorld.txt")
            .getBlockBlobClient();

        // Upload data
        String data = "Hello world!";
        try (InputStream dataStream = new ByteArrayInputStream(data.getBytes(StandardCharsets.UTF_8))) {
            blobClient.upload(dataStream, data.length());
        }

        // Download data
        int dataSize = (int) blobClient.getProperties().getBlobSize();
        try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream(dataSize)) {
            blobClient.downloadStream(outputStream);
            String downloaded = new String(outputStream.toByteArray(), StandardCharsets.UTF_8);
            System.out.println("Downloaded: " + downloaded);
        }

        // List blobs
        containerClient.listBlobs().forEach(blobItem -> 
            System.out.println("Blob: " + blobItem.getName()));

        // Cleanup
        blobClient.delete();
        containerClient.delete();
    }
}

Source: SKILL.md on GitHub

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    This skill provides a comprehensive guide for interacting with Azure Blob Storage using the official Java SDK. It follows standard security practices for cloud development, such as using environment variables for secret management and official Microsoft libraries.

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Last checked against GitHub 20 hours ago.

Activeupdated 5 months ago

Capability

Other metadata
metadata
{
  "author": "Microsoft",
  "version": "1.0.0",
  "package": "com.azure:azure-storage-blob"
}

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