There are many ways to use heroku, such as using Github and the command line, but it didn't work when I looked at it, so here for those who didn't work as well and my memorandum. I will write it. This is pretty easy to do.
A war file is a compressed file of the entire application.
This command enables the heroku deploy command.
heroku plugins:install heroku-cli-deploy
heroku deploy: war dist / app name.war
The dist part is the path. Please note that not found will be displayed if the path is incorrect.