Microservice architectures are all the rage in JavaLand. They allow teams to develop services independently and deploy autonomously. Why microservices? IF you are developing a large/complex application AND you need to deliver it rapidly, frequently, and reliably over a long period of time THEN the Microservice Architecture is often a good choice. Reactive architectures are becoming increasingly popular for organizations that need to do more, with less hardware. Reactive programming allows you to build systems that are resilient to high load. In this session, I'll show you how to use JHipster to create a reactive microservices architecture with Spring Boot, Spring Cloud, Keycloak, and run it all in Docker. You will leave with the know-how to create your own resilient apps! Related blog post: https://developer.okta.com/blog/2021/01/20/reactive-java-microservices YouTube demo: https://youtu.be/clkEUHWT9-M GitHub repo: https://github.com/oktadev/java-microservices-examples/tree/main/reactive-jhipster

1. Reactive Java Microservices
with Spring Boot and JHipster
May 26, 2022
Matt Raible | @mraible
Photo by Ken Cheung
https://unsplash.com/photos/VbLTNceBTFE

3. What is JHipster?

4. How to Use JHipster
Install JHipster using npm:
npm install -g generator-jhipster
Create a directory and cd into it:
take app
Run it!
jhipster

5. Monolith, Gateway, or Microservices?
Spring MVC or Spring WebFlux?
Authentication Type?
Database Type?
Build Tool?
Web Framework?
JHipster Options

6. https://start.jhipster.tech

7. Thriving OSS Project
Started by Julien Dubois on October 21, 2013
App Generator, Platform, Learning Tool …

8. @mraible
Hi, I’m Matt Raible
Father, Husband, Skier, Mountain
Biker, Whitewater Rafter
Bus Lover
Web Developer and Java Champion
Okta Developer Advocate
Blogger on raibledesigns.com and
developer.okta.com/blog
@mraible

12. developer.okta.com

13. Spring
History of Spring
October 2002 - Rod Johnson writes
J2EE Design & Development
2004 - Spring 1.0
2006 - Spring 2.0 with better XML
2009 - JavaConfig
2014 - Spring Boot 1.0
2015 - Spring Cloud 1.0
🍃

14. Microservices Visionaries

15. “Any organization that designs a system
(defined broadly) will produce a design
whose structure is a copy of the
organization's communication structure.”
Conway’s Law
Melvin Conway 1967

17. “Do one thing and do it well.”

20. Spring WebFlux!

21. Spring MVC Code
@PostMapping("/points")
public ResponseEntity<Points> createPoints(@Valid @RequestBody Points points) throws URISyntaxException {
log.debug("REST request to save Points : {}", points);
if (points.getId() != null) {
throw new BadRequestAlertException("A new points cannot already have an ID", ENTITY_NAME, "idexists");
}
Points result = pointsRepository.save(points);
pointsSearchRepository.save(result);
return ResponseEntity
.created(new URI("/api/points/" + result.getId()))
.headers(HeaderUtil.createEntityCreationAlert(
applicationName, true, ENTITY_NAME, result.getId().toString()))
.body(result);
}

22. Spring WebFlux Code
@PostMapping("/points")
public Mono<ResponseEntity<Points>> createPoints(@Valid @RequestBody Points points) throws URISyntaxException {
log.debug("REST request to save Points : {}", points);
if (points.getId() != null) {
throw new BadRequestAlertException("A new points cannot already have an ID", ENTITY_NAME, "idexists");
}
return pointsRepository
.save(points)
.flatMap(pointsSearchRepository::save)
.map(
result -> {
try {
return ResponseEntity
.created(new URI("/api/points/" + result.getId()))
.headers(HeaderUtil.createEntityCreationAlert(
applicationName, true, ENTITY_NAME, result.getId().toString()))
.body(result);
} catch (URISyntaxException e) {
throw new RuntimeException(e);
}
}
);
}

23. Spring Cloud Gateway

24. yelp.com/callback
Back to redirect URI
with authorization code
Exchange code for
access token and ID token
accounts.google.com
Email
**********
Go to authorization server
Redirect URI: yelp.com/cb
Scope: openid profile
Authorization Server
yelp.com
Connect with Google
Resource owner
Client
accounts.google.com
Allow Yelp to access your public
profile and contacts?
No Yes
Request consent
from resource owner
Hello Matt!
accounts.google
Get user info
with access token
/userinfo
OAuth 2.0 and OIDC

26. Demo
Create microservices with JDL
Run apps and e2e tests
Switch identity providers
Run everything with Docker
https://github.com/oktadev/java-
microservices-examples
🤓

27. Reactive Microservices with Spring Cloud Gateway
https://developer.okta.com/blog/2019/08/28/reactive-microservices-spring-cloud-gateway

28. What You Learned

29. https://developer.okta.com/blog/2021/01/20/reactive-java-microservices

30. https://developer.okta.com/blog/2021/06/01/kubernetes-spring-boot-jhipster

31. npm install -g generator-jhipster-kotlin

32. https://wiki.openjdk.java.net/display/loom/Main

33. What’s Next for JHipster?
Micro Frontends
Spring Native
GraphQL
* These are my personal interests.

34. JHipster is Knowledge

35. The JHipster Mini-Book
Written with Asciidoctor
Free download from InfoQ:
infoq.com/minibooks/jhipster-mini-book
Quick and to the point, 164 pages
Developed a real world app:
www.21-points.com
Buy for $20 or download for FREE

36. The Angular Mini-Book
Written with Asciidoctor
Free download from InfoQ:
infoq.com/minibooks/angular-mini-book
Angular 13 and Spring Boot 2.6
Angular Material, Bootstrap, Kotlin
Spring Security and best practices
Deploy separate apps and single artifact

37. Learn More
stackoverflow.com
Spring Boot
spring.io/guides
JHipster
www.jhipster.tech
Okta APIs
developer.okta.com

38. developer.okta.com/blog
@oktadev

39. Action: Try JHipster! 🚀
npm i -g generator-jhipster@7

40. git clone https://github.com/oktadeveloper/okta-spring-webflux-react-
example.git
https://github.com/oktadev/java-microservices-examples
Use the Source, Luke!

41. developer.okta.com

42. Thanks!
Keep in Touch
raibledesigns.com
@mraible
Presentations
speakerdeck.com/mraible
Code
github.com/oktadev
developer.okta.com