Spring Framework 5.0 Themes and Trends

Preparing for the challenges of 2017 and beyond, Spring Framework 5 focuses on several key themes:. In particular reactive web applications, comprehensive support for JDK 9, and a general focus on lambda-oriented programmatic setup This keynote introduces Spring Framework 5.0 towards the end of its milestone phase and presents selected feature highlights.

Transcript

1. Spring 5 Themes & Trends Stéphane Nicoll - @snicoll
2. Last 4.x feature release: 4.3 2 • Released on June 2016 • Extended support life until 2019 • on JDK 6, 7, 8 • on Tomcat 6, 7, 8.0, 8.5 • on WebSphere 7, 8.0, 8.5 and 9 • Programming model refinements brought forward to JDK 6+ • DI & MVC refinements • Composed annotations
3. A new framework generation for 2017+ 3 • 5.0 GA available • Spring Boot 2.0 M5 next week! • Major baseline upgrade • JDK 8+ and JavaEE 7 (Servlet 3.1+, Bean Validation 1.1, JMS 2.0+, JPA 2.1+) • Support of JUnit 5 (next to JUnit 4.12) • Comprehensive integration with JavaEE 8 API level • Servlet 4.0, Bean Validation 2.0, JPA 2.2, JSON Binding API 1.0 • e.g. Tomcat 9.0, Hibernate Validator 6.0, Apache Johnzon 1.1
4. @snicoll 4 JDK 9
5. @snicoll 5 HTTP/2
6. @snicoll 6 Reactive Spring
7. 7 ∞
8. 8 Going Reactive: More for scalability and stability than for speed
9. Blocking + Thread pools 9 HTTP request HTTP response ⏳ ⚙ ⏳ ✍ ⏳ Thread
10. Non-blocking and event-loop 10 IO Selector Thread Worker Threads ⚙ ⚙ ✍ ✍ ⚙ ⚙ ✍ ✍ ⚙ ⚙ ✍
11. 11 From blocking to event-based Neutral to latency
12. Imperative style 12 public interface PersonRepository {
 
 Person findById(String id);
 
 List<Person> findAll();
 
 void save(Person person);
 
 } try {
 Person p = personRepository.findById(id);
 // ...
 handle(p);
 }
 catch (IOException ex) {
 // ...
 } Blocking
13. Functional style 13 personRepository.findById(id)
 .map(this::handle)
 .subscribe(); public interface PersonRepository {
 
 Mono<Person> findById(String id);
 
 Flux<Person> findAll();
 
 Mono<Void> save(Person person);
 
 } Neutral to latency (event based)
14. Reactive Streams 14 Publisher Subscriber subscribe request(n) Backpressure Error|Complete onNext(data) onNext(data) onNext(data)
15. Reactive Streams API 15 public interface Publisher<T> { void subscribe(Subscriber<? super T> s); } public interface Subscriber<T> { void onSubscribe(Subscription s); void onNext(T t); void onError(Throwable t); void onComplete(); } public interface Subscription { void request(long n); void cancel(); } public interface Processor<T, R> extends Subscriber<T>, Publisher<R> { }
16. Functional style 16 personRepository.findById(id)
 .map(this::handle)
 .subscribe(); public interface PersonRepository {
 
 Mono<Person> findById(String id);
 
 <Person> findAll();
 
 Mono<Void> save(Person person);
 
 } Neutral to latency (event based) Flux
17. 17 <T> is a Publisher<T> for 0..n elements Flux
18. 18 Mono<T> is a Publisher<T> for 0..1 element
19. @snicoll Demo
21. Reactive Web Controller 21 @GetMapping("/users/{id}")
 Mono<User> getById(@PathVariable String id) {
 return this.userRepository.findOne(id);
 }
 
 @GetMapping("/users")
 Flux<User> all() {
 return this.userRepository.findAll();
 }
 
 @PostMapping("/users")
 Mono<Void> save(@RequestBody Mono<User> user) {
 return this.userRepository.save(user).then();
 }
22. New Web Client API 22 WebClient client = WebClient.create(); Mono<GithubUser> githubUser = client .get() .uri("https://api.github.com/users/{username}", username) .retrieve() .bodyToMono(GithubUser.class); Mono<TwitterUser> twitterUser = client .get() .uri("https://api.twitter.com/1.1/users/show.json?screen_name={username}", username) .retrieve() .bodyToMono(TwitterUser.class); return githubUser.and(twitterUser, (github, twitter)-> new AppUser(github, twitter));
23. 23 @Controller, @RequestMapping Spring MVC Servlet API Servlet Container Spring WebFlux.fn Servlet 3.1, Netty, Undertow Spring WebFlux HTTP / Reactive Streams
24. @snicoll 24 Functional APIs
25. Functional bean registration API (work in progress) 25 • Alternative mechanism to configure the ApplicationContext • Full control over beans registration public static void main(String[] args) { GenericApplicationContext ctx = new GenericApplicationContext(); ctx.registerBean(A.class); ctx.registerBean(B.class, () -> new B(ctx.getBean(A.class))); ctx.refresh(); }
26. Functional-style web routing 26 RouterFunction<?> route =
 route(GET("/users"), )
 .and(route(GET("/users/{id}"), )
 .and(route(POST("/users"), ))); request -> {
 Flux<User> people = repository.findAll();
 return ServerResponse.ok().body(people, User.class);
 } request -> {
 String personId = request.pathVariable("id");
 Mono<User> person = repository.findById(personId);
 return ServerResponse.ok().body(person, User.class);
 } request -> {
 Mono<User> user = request.bodyToMono(User.class);
 return ServerResponse.ok().build(repository.saveAll(user).then());
 }
27. Functional-style web routing 27 RouterFunction<?> route =
 route(GET(“/users"), )
 .and(route(GET(“/users/{id}”), )
 .and(route(POST(“/users”), ))); this::findAll this::findById this::save
28. @snicoll 28 Kotlin Support
29. Type inference 29 @RestController class UserController(val repo: UserRepository) { @GetMapping("/user/{id}") fun findOne(@PathVariable id: String): Mono<User> { } @GetMapping("/user") fun findAll() : Flux<User> { } } return repo.findOne(id) return repo.findAll()
30. Type inference 30 @RestController class UserController(val repo: UserRepository) { @GetMapping("/user/{id}") fun findOne(@PathVariable id: String) = @GetMapping("/user") fun findAll() : Flux<User> = } repo.findOne(id) repo.findAll()
31. Extensions 31 fun findAll(request: ServerRequest): Mono<ServerResponse> { } inline fun <reified T : Any> ServerResponse.BodyBuilder .body(publisher: Publisher<T>) = body(publisher, T::class.java) ServerResponseExtensions provided by spring-webflux return ok().body(repo.findAll(), User::class.java)
32. Extensions 32 fun findAll(request: ServerRequest) = inline fun <reified T : Any> ServerResponse.BodyBuilder .body(publisher: Publisher<T>) = body(publisher, T::class.java) ServerResponseExtensions provided by spring-webflux ok().body(repo.findAll())
33. Leverage Kotlin nullable information 33 @GetMapping("/foo") fun foo(@RequestParam( ) bar: String?) = … http://localhost:8080/foo required = false
34. Leverage Kotlin nullable information 34 @GetMapping("/foo") fun foo(@RequestParam bar: String?) = … http://localhost:8080/foo
35. Custom DSL 35 nest( ), route( . andRoute( ). andNest( ), . . ); path("/blog").and(accept(TEXT_HTML) GET("/"), blogHandler::findAllView) GET("/{slug}"), blogHandler::findOneView) path("/api/blog").and(accept(APPLICATION_JSON) route(GET("/"), blogHandler::findAll) andRoute(GET("/{id}"), blogHandler::findOne) andRoute(POST("/"), blogHandler::create)
36. Custom DSL 36 router { ( ).nest { } ( ).nest { } } "/blog" and accept(TEXT_HTML) GET("/", blogHandler::findAllView) GET("/{slug}", blogHandler::findOneView) "/api/blog" and accept(APPLICATION_JSON) GET("/", blogHandler::findAll) GET("/{id}", blogHandler::findOne) POST("/", blogHandler::create)
37. And many more… 37 https://goo.gl/gMnhxN
38. @snicoll Demo
39. Try it today: start.spring.io 39
40. 40 Thank You! @snicoll