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
   

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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
   

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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
   

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4. @snicoll
   4
   JDK 9
   
   

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5. @snicoll
   5
   HTTP/2
   
   

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6. @snicoll
   6
   Reactive Spring
   
   

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7. 7
   
   
   ∞
   

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8. 8
   Going Reactive:
   More for scalability and stability than for speed
   

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9. Blocking + Thread pools
   9
   HTTP request
   HTTP response
   
   ⏳
   ⚙
   ⏳
   ✍
   ⏳
   Thread
   

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10. Non-blocking and event-loop
    10
    IO Selector Thread Worker Threads
    
    
    ⚙ ⚙ ✍
    ✍ ⚙
    ⚙
    ✍ ✍ ⚙
    ⚙ ✍
    

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11. 11
    From blocking to event-based
    Neutral to latency
    

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12. Imperative style
    12
    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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13. Functional style
    13
    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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14. Reactive Streams
    14
    Publisher Subscriber
    subscribe
    request(n)
    Backpressure
    Error|Complete
    onNext(data)
    onNext(data)
    onNext(data)
    

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15. Reactive Streams API
    15
    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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16. Functional style
    16
    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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17. 17
    is a Publisher for 0..n elements
    Flux
    

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18. 18
    Mono is a Publisher for 0..1 element
    

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19. @snicoll
    Demo
    

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21. Reactive Web Controller
    21
    @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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22. New Web Client API
    22
    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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23. 23
    @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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24. @snicoll
    24
    Functional APIs
    
    

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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();
    }
    

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26. Functional-style web routing
    26
    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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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
    

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28. @snicoll
    28
    Kotlin Support
    
    

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29. Type inference
    29
    @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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30. Type inference
    30
    @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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31. Extensions
    31
    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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32. Extensions
    32
    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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33. Leverage Kotlin nullable information
    33
    @GetMapping("/foo")
    fun foo(@RequestParam( ) bar: String?) = …
    http://localhost:8080/foo
    required = false
    

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34. Leverage Kotlin nullable information
    34
    @GetMapping("/foo")
    fun foo(@RequestParam bar: String?) = …
    http://localhost:8080/foo
    

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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)
    

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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)
    

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37. And many more…
    37
    https://goo.gl/gMnhxN
    

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38. @snicoll
    Demo
    

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39. Try it today: start.spring.io
    39
    

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40. 40
    Thank You!
    @snicoll
    

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