In any web portal, to access a file stored in an Azure Blob Storage account container, we need to connect to the Azure Blob Storage Account and construct the download link for the specified file using its name and Azure storage account details. Constructed Azure Blob URLs can also be used to upload a file and delete a file from the web portal using Java code. 

A shared access signature (SAS) enables you to grant limited access to containers and blobs in your storage account. When you create a SAS, you specify its constraints, including which Azure Storage resources a client is allowed to access, what permissions they have on those resources, and how long the SAS is valid.