Oauth 2.0 client authentication flow with Spring with apiKey and apiSecret

I would like to use the spring framework for client authentication but I have an unusual message format to retrieve the bearer token. The closest is client_secret_post but not quite. Below is the curl call that the application needs to match.

curl -H "Accept: application/json" -H "Content-Type: application/x-www-form-urlencoded"  -d 'apiKey={key}&apiSecret={secret}' {url}