A simple demo SpringBoot application deployment process to Heroku using Hibernate JPA Implementation.

It's here mostly for me to have it at hand, but I thought it might help somebody else as well.

Navigate to folder containing Spring Application. Tip: Create it with https://start.spring.io/. Set Java version to 11 and check if you have the same version of java with java -version in terminal, otherwise it won't work.

You must use following dependencies: Spring Web, Lombok, PostgreSQL Driver, Spring Data JPA. (Those can be added from https://start.spring.io/)

You should use Spring Boot DevTools dependency for LiveReload and Fast restart.

You need also to put manually this dependency after you open your project:

https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient/4.5.2

Create a system.properties file in root folder of the project with java.runtime.version=11 inside it. Java version must match java version in pom.xml

Add the following lines in src/main/resources/application.properties:

# You can get all the variables using the command that gets the full database url from the bottom of this page
# Or by going to your app on Heroku -> Resources -> Heroku Postgres -> Settings -> View Credentials
spring.jpa.hibernate.ddl-auto=create-drop     // create-drop used in development, consult documentation for proper value
spring.datasource.url=postgres://username:password@host:port/database 
spring.datasource.username=username
spring.datasource.password=password

In terminal:

> heroku login
> git init
> git add .
> git commit -m "Initial commit"
> heroku create

If you want to rename your app, you can use:

> heroku apps:rename <new-name> # (works only if in current app repo, else you must supply the app name -check Heroku documentation) 

Go to Heroku site, and add postgres addon to your app from resources tab of your app, or do it from the console. You can check if the addon is added with:

> heroku addons

Add Controller, Model, Repository and Service classes.

IMPORTANT! Check the ones provided in this project to see how Heroku interacts with them.

If you want to push your project on Github:

> git remote add origin <your-git-repo>  
> git add .
> git commit -m "Your commit message"
> git push origin <branch-name>

To deploy your app to Heroku:

> git add .
> git commit -m "Your commit message"
> git push heroku master 

If you're locally on another branch than master, use:

> git push heroku <local-branch-name>:master

You can check your database connection with https://www.postman.com/
When making an HTTP Request, use the Java variable name set in the Model class. (In my case is 'name') Ex.: for a POST Request:

https://<your-app-name>.herokuapp.com/api/<path-name> NOTE: /api/ is our path from the ControllerClass

{
  "name": "The new name"
}

Useful commands:

> heroku logs --tail # continually stream logs
> heroku logs --num=num # number of lines to display
> heroku addons # see enabled heroku addons, in our app we should have heroku postgres
> heroku pg:psql # connect to psql shell

To save your full database url locally in a file: (You can name it whatever you want, I named it HEROKU_POSTGRESQL)

#---Windows Powershell
> heroku config > HEROKU_POSTGRESQL 

#---Linux shell
> heroku config | grep HEROKU_POSTGRESQL