I would like to develop a web application with angular4 as front end and spring boot as back end first ,and after that create the android version .

searching in google i found that there is a lot of methods , the first one is create a Spring boot project which includes an angular 4 folder (generated with angular CLI ) which means one project in total .

the second one : completly separate the 2 projects , one for spring , the other for angular4 , and the client will use the api Rest to communicate with spring tools.

which one is the best method ? 

thanks in advance.