azureblobstoragedownload

Azure Blob Storage Download Java example

This folder contains a Java application example that handles Blob storage on Microsoft Azure.

Download a Blob from a Blob Storage container in an Azure storage account.

Requirements

• You must have a Microsoft Azure subscription.

• You must have the following installed:

  • Java Development Kit (JDK) 8
  • Apache Maven 3
  • Azure CLI

• The code was written for:

  • Java 8
  • Apache Maven 3
  • Azure SDK for Java: New Client Libraries (Azure Blob Storage library v12) (com.azure)

Using the code

• Sign in Azure (Interactively).

  The Azure CLI's default authentication method for logins uses a web browser and access token to sign in.

  1. Run the Azure CLI login command.

     az login

     If the CLI can open your default browser, it will do so and load an Azure sign-in page.

     Otherwise, open a browser page at https://aka.ms/devicelogin and enter the authorization code displayed in your terminal.

     If no web browser is available or the web browser fails to open, use device code flow with az login --use-device-code.

  2. Sign in with your account credentials in the browser.

  Make sure you select your subscription by:

  az account set --subscription <name or id>

• Create a storage account.

  An Azure storage account contains all of your Azure Storage data objects: blobs, file shares, queues, tables, and disks. The storage account provides a unique namespace for your Azure Storage data that's accessible from anywhere in the world over HTTP or HTTPS. Data in your storage account is durable and highly available, secure, and massively scalable.

  An storage account can content containers and every container can content blobs.

  Storage Account
              ├── Container_1/
              │   ├── Blob_1_1/
              │   └── Blob_1_2/
              │
              └── Container_2/
                  ├── Blob_2_1/
                  ├── Blob_2_2/
                  └── Blob_2_3/

  Create a storage account using the Azure portal:

  1. Select the Storage account option and choose Create.
  2. Select the Subscription in which you want to create the new storage account.
  3. Select the Resource Group for your storage account.
  4. Enter a name for your storage account.
  5. Select the Region for your storage account.
  6. Select the Performance to be used.
  7. Select the Redundancy to be used.
  8. Click Create to create the storage account.

• Configure your application.

  A connection string includes the authentication information required for your application to access data in an Azure Storage account at runtime.

  Your application needs to access the connection string at runtime to authorize requests made to Azure Storage.

  You can find your storage account's connection strings in the Azure portal:

  1. Navigate to Storage Account.
  2. Select your storage account.
  3. Select Access keys and you can see your Storage account name, connection strings and account keys.

  The connection string looks like this:

  DefaultEndpointsProtocol=https;AccountName=<ACCOUNT_NAME>;AccountKey=<ACCOUNT_KEY>;EndpointSuffix=core.windows.net

  The application configuration is stored in the app.properties properties file, located in the path src/main/resources. The file content is:

  StorageAccountConnectionString=<STORAGE_ACCOUNT_CONNECTION_STRING>

  You must edit the app.properties file and replace the values of:

  • <STORAGE_ACCOUNT_CONNECTION_STRING> by the connection string of your storage account.

  The application uses this information for accessing your Azure storage account.

• Run the code.

  You must provide 3 parameters, replace the values of:

  • <CONTAINER_NAME> by name of the container.
  • <BLOB_NAME> by blob name in the container.
  • <LOCAL_FILE_NAME> by local file name.

  Run application:

  java -jar azureblobstoragedownload.jar <CONTAINER_NAME> <BLOB_NAME> <LOCAL_FILE_NAME>

• Test the application.

  You should see the new file created in your local destiny from the Blob Storage container in an Azure storage account.