how to fetch the token using basic Auth in REST api

Question

I have a requirement to call the REST webservice to fetch the file and transfer to a folder (REST - SAP PO - SFTP).

Before calling the actual REST api to fetch file, I need to call a Login REST api using basic authorization which will return the Token and logon key which has to be passed in second REST api and content-type is “application/x-www-form-urlencoded".

Login Input format: Call the URL via POST method with JSON object serialized and set parameter.

obj={
  "login":"[email protected]",
  "pword":"my_password"
}

NOTE: To make the request calls, a JSON object will need to be created and passed as a POST form parameter obj={jsonObject}

How can we send object using REST adapter?