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Spring 5 Themes & Trends
Stéphane Nicoll - @snicoll
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Last 4.x feature release: 4.3
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• 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
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A new framework generation for 2017+
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• 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
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@snicoll
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JDK 9
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@snicoll
5
HTTP/2
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@snicoll
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Reactive Spring
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∞
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Going Reactive:
More for scalability and stability than for speed
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Blocking + Thread pools
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HTTP request
HTTP response
⏳
⚙
⏳
✍
⏳
Thread
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Non-blocking and event-loop
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IO Selector Thread Worker Threads
⚙ ⚙ ✍
✍ ⚙
⚙
✍ ✍ ⚙
⚙ ✍
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From blocking to event-based
Neutral to latency
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Imperative style
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public interface PersonRepository {
Person findById(String id);
List findAll();
void save(Person person);
}
try {
Person p = personRepository.findById(id);
// ...
handle(p);
}
catch (IOException ex) {
// ...
}
Blocking
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Functional style
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personRepository.findById(id)
.map(this::handle)
.subscribe();
public interface PersonRepository {
Mono findById(String id);
Flux findAll();
Mono save(Person person);
}
Neutral to latency
(event based)
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Reactive Streams
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Publisher Subscriber
subscribe
request(n)
Backpressure
Error|Complete
onNext(data)
onNext(data)
onNext(data)
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Reactive Streams API
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public interface Publisher {
void subscribe(Subscriber super T> s);
}
public interface Subscriber {
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 extends Subscriber, Publisher {
}
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Functional style
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personRepository.findById(id)
.map(this::handle)
.subscribe();
public interface PersonRepository {
Mono findById(String id);
findAll();
Mono save(Person person);
}
Neutral to latency
(event based)
Flux
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is a Publisher for 0..n elements
Flux
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Mono is a Publisher for 0..1 element
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@snicoll
Demo
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Reactive Web Controller
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@GetMapping("/users/{id}")
Mono getById(@PathVariable String id) {
return this.userRepository.findOne(id);
}
@GetMapping("/users")
Flux all() {
return this.userRepository.findAll();
}
@PostMapping("/users")
Mono save(@RequestBody Mono user) {
return this.userRepository.save(user).then();
}
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New Web Client API
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WebClient client = WebClient.create();
Mono githubUser = client
.get()
.uri("https://api.github.com/users/{username}", username)
.retrieve()
.bodyToMono(GithubUser.class);
Mono 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));
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@Controller, @RequestMapping
Spring MVC
Servlet API
Servlet Container
Spring WebFlux.fn
Servlet 3.1, Netty, Undertow
Spring WebFlux
HTTP / Reactive Streams
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@snicoll
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Functional APIs
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Functional bean registration API (work in progress)
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• 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();
}
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Functional-style web routing
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RouterFunction> route =
route(GET("/users"),
)
.and(route(GET("/users/{id}"),
)
.and(route(POST("/users"),
)));
request -> {
Flux people = repository.findAll();
return ServerResponse.ok().body(people, User.class);
}
request -> {
String personId = request.pathVariable("id");
Mono person = repository.findById(personId);
return ServerResponse.ok().body(person, User.class);
}
request -> {
Mono user = request.bodyToMono(User.class);
return ServerResponse.ok().build(repository.saveAll(user).then());
}
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Functional-style web routing
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RouterFunction> route =
route(GET(“/users"), )
.and(route(GET(“/users/{id}”), )
.and(route(POST(“/users”), )));
this::findAll
this::findById
this::save
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@snicoll
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Kotlin Support
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Type inference
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@RestController
class UserController(val repo: UserRepository) {
@GetMapping("/user/{id}")
fun findOne(@PathVariable id: String): Mono {
}
@GetMapping("/user")
fun findAll() : Flux {
}
}
return repo.findOne(id)
return repo.findAll()
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Type inference
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@RestController
class UserController(val repo: UserRepository) {
@GetMapping("/user/{id}")
fun findOne(@PathVariable id: String) =
@GetMapping("/user")
fun findAll() : Flux =
}
repo.findOne(id)
repo.findAll()
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Extensions
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fun findAll(request: ServerRequest): Mono {
}
inline fun ServerResponse.BodyBuilder
.body(publisher: Publisher) = body(publisher, T::class.java)
ServerResponseExtensions provided by spring-webflux
return ok().body(repo.findAll(), User::class.java)
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Extensions
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fun findAll(request: ServerRequest) =
inline fun ServerResponse.BodyBuilder
.body(publisher: Publisher) = body(publisher, T::class.java)
ServerResponseExtensions provided by spring-webflux
ok().body(repo.findAll())
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Leverage Kotlin nullable information
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@GetMapping("/foo")
fun foo(@RequestParam( ) bar: String?) = …
http://localhost:8080/foo
required = false
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Leverage Kotlin nullable information
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@GetMapping("/foo")
fun foo(@RequestParam bar: String?) = …
http://localhost:8080/foo
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Custom DSL
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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)
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Custom DSL
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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)
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And many more…
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https://goo.gl/gMnhxN
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@snicoll
Demo
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Try it today: start.spring.io
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Thank You!
@snicoll