Develop for Azure Files with Java

Here’s a concise summary of the article "Develop for Azure Files with Java":

Overview

• Azure Files provides managed file shares in the cloud accessible via SMB, NFS, and a REST API (FileREST). Java apps can use standard file I/O (when shares are mounted), the File Shares client library (data-plane REST operations), or the Azure Storage management libraries (resource management via ARM).

• The article explains when to use each approach and includes examples for common tasks.

When to use each approach

• Java file I/O libraries (java.io, java.nio): Use when an Azure file share is mounted (SMB/NFS) and you want minimal code changes for existing apps that use local file APIs.

• File REST API / File Shares client library (com.azure.storage.file.share): Use for advanced features, high-scale data-plane operations, custom cloud integrations, or features not available via native SMB/NFS.

• Storage resource provider REST API / Azure Storage management libraries: Use for file service or file-share level management operations (create/delete shares, configure quotas, list snapshots) via Azure Resource Manager.

Prerequisites

• Azure subscription and storage account

• JDK 8+ and a build tool (example uses Maven)

• Appropriate Azure SDK dependencies (examples show using azure-sdk-bom or direct dependencies like azure-storage-file-share, azure-identity, azure-resourcemanager, etc.)

• Necessary import directives for both SDK and standard Java I/O

Setup and packaging

• Examples show how to add the BOM or direct Maven dependencies and include required import statements in code.

Working via Java file I/O (when share is mounted)

• Mount a share (links provided for mounting SMB/NFS on Windows/Linux).

• Examples:

  • Enumerate directories using java.io/File and print names.

  • Write and append text using java.nio.file.Files.

  • Lock a file using FileChannel/FileLock (note: SMB file system locks are OS-managed).

  • Enumerate ACLs using AclFileAttributeView.

• Note: SMB uses OS-level file locks while the FileREST API uses leases — see guidance on managing lock interactions.

Using the File Shares client library (data-plane REST)

• Use ShareClient/ShareDirectoryClient/ShareFileClient for programmatic file and directory operations.

• Authorization examples:

  • DefaultAzureCredential (recommended) for OAuth-based auth.

  • StorageSharedKeyCredential (account key) or connection strings (include account key).

  • Security guidance: prefer DefaultAzureCredential; handle account keys with caution.

• Example tasks:

  • Copy files between shares using beginCopy and a SyncPoller.

  • Lease a file (acquire/release) using ShareLeaseClient (leases provide exclusive write/delete access across clients).

  • Create and list share snapshots using a ShareServiceClient / ShareClient; note snapshot operations at share-level require account key (not OAuth tokens).

Using the Azure Storage management libraries (control-plane / ARM)

• Use AzureResourceManager and storage management clients to perform resource-level tasks (register Microsoft.Storage, create shares, set quotas, list shares and snapshots).

• Examples:

  • Create a file share with a specified quota using FileSharesClient.

  • List file shares and snapshots with FileSharesClient.

• Note: Registration operations require appropriate RBAC permissions (e.g., Microsoft.Storage/register/action).

Security and authorization highlights

• DefaultAzureCredential (Azure Identity) is recommended for secure, passwordless authentication.

• Account keys and connection strings allow full access but pose security risks; use only when necessary and consider secure storage (e.g., Key Vault).

Next steps / references

• Links to deeper resources: developer overview for Azure Files, naming rules, file lock guidance, directory and file REST operations, and SDK references.

The article includes full code examples for each approach and links to platform-specific mounting and authentication guidance.