import org.springframework.core.io.Resource
        public Resource downloadFile() {
             Resource resource;
             DataLakeFileClient fileClient = fileSystemClient.getFileClient("test.txt"); // fileSystemClient is the container location
        
             // code to fetch content present in file client object and assign it to resource;
        
             return resource;
        }

import com.azure.storage.blob.BlobClient;
import com.azure.storage.blob.BlobContainerClient;
import com.azure.storage.blob.BlobServiceClient;
import com.azure.storage.blob.BlobServiceClientBuilder;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
@RestController
public class DownloadFile {
    @GetMapping("/download-file")
    public ResponseEntity<Resource> downloadFile() {
        String sasToken = "<storage_account_SAS_Token>"; 
        String accountName = "<Account_name>";
        String containerName = "<Container_Name>"; 
        String fileName = "<Blob_Nmae>";
        BlobServiceClient blobServiceClient = new BlobServiceClientBuilder()
                .endpoint("https://" + accountName + ".dfs.core.windows.net")
                .sasToken(sasToken)
                .buildClient();
        BlobContainerClient containerClient = blobServiceClient.getBlobContainerClient(containerName);
        BlobClient blobClient = containerClient.getBlobClient(fileName);
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        blobClient.download(outputStream);
        final byte[] bytes = outputStream.toByteArray();
        Resource resource = new ByteArrayResource(bytes);
        HttpHeaders headers = new HttpHeaders();
        headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + fileName + "\"");
        System.out.println("Blob downloaded successfully: " + fileName);
        return ResponseEntity.ok()
                .contentType(MediaType.APPLICATION_OCTET_STREAM)
                .headers(headers)
                .body(resource);
    }
}

<dependencies>
       <dependency>
            <groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-web</artifactId>
	</dependency>
	<dependency>
	    <groupId>com.azure.spring</groupId>
	    <artifactId>spring-cloud-azure-starter-storage</artifactId>
	</dependency>
	<dependency>
            <groupId>com.azure</groupId>
            <artifactId>azure-storage-file-datalake</artifactId>
            <version>12.16.0</version>
        </dependency>
	<dependency>
	    <groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-test</artifactId>
	    <scope>test</scope>
	</dependency>
</dependencies>