Spring Framework 5 & Spring Boot 2.0

Slides of the talk I gave at W-JAX 2017.

@springcentral

Transcript

1. Spring Framework 5
   & Spring Boot 2.0
   / olivergierke
   Oliver Gierke ƀ ogierke@pivotal.io
   Modern Enterprise Java in 2018
   

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2. https://github.com/olivergierke/spring-five-functional-reactive
   Sample Code
   2
   

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3. Spring Framework 5
   3
   

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4. Infrastructure
   4
   

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5. Infrastructure
   • JavaSE 8 baseline
   • JDK 9 compatibility through automatic modules and JDK 9 base CI builds
   • JavaEE 7 baseline
   • Servlet API 3.1
   • JPA 2.1 (OpenJPA support dropped)
   • JMS 2.0
   • Bean Validation 1.1
   • Support for selected JavaEE 8 APIs
   • Servlet 4
   • Bean Validation 2.0
   • JSON Binding API
   5
   

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6. JDK 9 Support
   • Many general JVM improvements
   • Compact Strings
   • G1 by default
   • TLS protocol stack
   • Jigsaw
   • Stable automatic module names
   • We currently recommend to still run in classpath mode
   6
   

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7. HTTP/2 Support
   • Mostly via Servlet 4.0
   • HTTP/2 support in Servlet containers
   • PushBuilder API
   7
   

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8. JUnit 5
   • Test context framework support
   • for both JUnit 4 and JUnit 5
   • Dependency injection capabilities inspired by Spring
   • Constructor injection
   • Parameter injection á la Spring MVC
   • Meta annotation support inspired by Spring
   8
   @RunWith(SpringJUnit4ClassRunner.class)
   @ContextConfiguration(…)
   public class MyTest { … }
   

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9. JUnit 5
   • Test context framework support
   • for both JUnit 4 and JUnit 5
   • Dependency injection capabilities inspired by Spring
   • Constructor injection
   • Parameter injection á la Spring MVC
   • Meta annotation support inspired by Spring
   8
   @SpringJUnitConfig(…)
   public class MyTest { … }
   

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10. Functional

    container extensions
    9
    

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11. Functional container extensions
    10
    GenericApplicationContext ctx = new GenericApplicationContext();

    

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12. Functional container extensions
    10
    GenericApplicationContext ctx = new GenericApplicationContext();

    // Default constructor via reflection

    ctx.registerBean(First.class);

    

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13. Functional container extensions
    10
    GenericApplicationContext ctx = new GenericApplicationContext();

    // Default constructor via reflection

    ctx.registerBean(First.class);

    // Explicit constructor via Supplier

    ctx.registerBean(Second.class,

    () -> new Second(ctx.getBean(First.class)));

    

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14. Functional container extensions
    10
    GenericApplicationContext ctx = new GenericApplicationContext();

    // Default constructor via reflection

    ctx.registerBean(First.class);

    // Explicit constructor via Supplier

    ctx.registerBean(Second.class,

    () -> new Second(ctx.getBean(First.class)));

    // Explicit constructor plus BeanDefinition customization

    ctx.registerBean(Third.class,

    () -> new Third(ctx.getBean(First.class)),

    bd -> bd.setLazyInit(true));
    

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15. A quick detour
    Reactive Programming
    11
    

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16. Reactive fundamentals
    12
    Publisher
    Subscriber
    Data
    Subscribe
    

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17. Reactive fundamentals
    12
    Publisher
    Subscriber
    Data
    Subscribe
    

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18. Reactive fundamentals
    12
    Publisher
    Subscriber
    Data
    Subscribe
    Business logic

    using operators
    ?
    

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19. Reactive programming 101
    13
    Mono.just("Hello")
    .map(word -> word.concat(" World!"))
    .subscribe(System.out::println);

    Flux.just("Hello", "World")
    .flatMap(word -> Flux.fromArray(word.split("")))
    .subscribe(System.out::println);
    

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20. Reactive programming 101
    14
    someMono
    .map(word -> word.concat("World"))
    .…
    someFlux
    .flatMap(word -> Flux.fromArray(word.split("")))
    .…
    

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21. Reactive programming 101
    15
    someMono // Created by the infrastructure
    .map(word -> word.concat("World"))
    .… // Handled by the infrastructure
    someFlux // Created by the infrastructure
    .flatMap(word -> Flux.fromArray(word.split("")))
    .… // Handled by the infrastructure
    

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22. Reactive programming 101
    16
    someMono // Created by the infrastructure
    .map(word -> word.concat("World"))
    .… // Handled by the infrastructure
    someFlux // Created by the infrastructure
    .flatMap(word -> Flux.fromArray(word.split("")))
    .… // Handled by the infrastructure
    

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23. Reactive programming
    • Subscription based
    • Push VS. pull model
    • Backpressure blurs the line
    • Two-phase execution
    • First: to build up the pipeline. Second: once the data starts flowing
    • Similar to programming model of the Java 8 Stream API
    • Lazy execution
    • Nothing happens until someone subscribes
    • Backpressure
    • Subscriber signals capability to handle the amount of data
    17
    

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24. Reactive programming
    • Optimized for resource usage, scalability and stability
    • Not necessarily faster
    • Optimized for „mean time to first result“
    • Challenge: debugging and tests
    • Needs non-blocking across the entire stack
    • Usage of blocking APIs (e.g. JDBC) severely complicates the picture and limits efficiency
    18
    

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25. Spring WebFlux
    19
    

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26. Runtime stacks
    20
    Servlet container Netty, Undertow, Servlet 3.1
    Servlet API Spring Web Reactive API
    Spring MVC Spring WebFlux(.fn)
    New!
    New!
    

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27. WebFlux Controller
    21
    @Controller
    class ReactiveUserController {
    private final UserRepository users;
    // Constructor for Dependency Injection
    @GetMapping("/users")

    Flux getUsers() {

    return this.repository.findAll();

    }

    }
    

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28. WebFlux Controller
    22
    @Controller
    class ReactiveUserController {
    private final UserRepository users;
    // Constructor for Dependency Injection
    @GetMapping("/users")

    Flux getUsers() {

    return this.repository.findAll();

    }

    }
    

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29. WebFlux Controller
    23
    @Controller
    class ReactiveUserController {
    // … continued
    @PostMapping("/users")
    Mono createUser(@RequestBody Mono user) {
    return user.flatMap(this.repository::save);
    }
    @GetMapping("/users/{id}/")
    Mono getUser(@PathVariable Long id) {
    return this.repository.findById(id);
    }
    }
    

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30. WebFlux Controller
    24
    @Controller
    class ReactiveUserController {
    // … continued
    @PostMapping("/users")
    Mono createUser(@RequestBody Mono user) {
    return user.flatMap(this.repository::save);
    }
    @GetMapping("/users/{id}/")
    Mono getUser(@PathVariable Long id) {
    return this.repository.findById(id);
    }
    }
    

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31. Spring WebFlux.fn
    25
    

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32. Functional controller
    26
    @Component
    class FunctionalUserController {
    private final UserRepository repository;
    // Constructor for Dependency Injection
    Mono getUser(ServerRequest request) {
    Mono user = Mono.just(request.pathVariable("id"))
    .flatMap(this.repository::findById);
    return ServerResponse.ok().body(user, User.class);
    }
    }
    

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33. Functional controller
    27
    @Component
    class FunctionalUserController {
    private final UserRepository repository;
    // Constructor for Dependency Injection
    Mono getUser(ServerRequest request) {
    Mono user = Mono.just(request.pathVariable("id"))
    .flatMap(this.repository::findById);
    return ServerResponse.ok().body(user, User.class);
    }
    }
    

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34. Functional controller
    28
    @Component
    class FunctionalUserController {
    // … continued
    Mono getUsers(ServerRequest request) {
    Flux users = this.repository.findAll();
    return ServerResponse.ok().body(users, User.class);
    }
    }
    

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35. Router Functions
    29
    @SpringBootApplication
    class ApplicationConfiguration {
    @Bean
    RouterFunction> routes(FunctionalUserController controller) {
    return RouterFunctions
    .route(GET("/users"), controller::getUsers)
    .andRoute(GET("/users/{id}"), controller::getUser);
    }
    }
    

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36. Kotlin Extensions
    30
    

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37. ApplicationContext extensions
    31
    // In GenericApplicationContextExtension.kt in spring-context

    

    inline fun GenericApplicationContext.registerBean(

    vararg customizers: BeanDefinitionCustomizer,

    crossinline function: (ApplicationContext) -> T) {

    

    registerBean(T::class.java, Supplier { function.invoke(this) }, *customizers)

    }
    

    // Allows …

    

    context.registerBean { Foo() }
    

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38. Functional routing with Kotlin
    32
    val router = router {

    val users = …

    accept(TEXT_HTML).nest {

    "/" { ok().render("index") }

    "/sse" { ok().render("sse") }

    "/users" {

    ok().render("users", mapOf("users" to users.map { it.toDto() }))

    }

    }
    ("/api/users" and accept(APPLICATION_JSON)) {

    ok().body(users)

    }

    }
    

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39. Bean definitions – Kotlin style
    33
    val databaseContext = beans {

    bean()

    bean()

    environment( { !activeProfiles.contains("cloud") } ) {

    bean {

    CommandLineRunner { initializeDatabase(ref()) }

    }

    }
    }

    

    fun initializeDatabase(userRepository: UserRepository) { // ... }
    

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40. Miscellaneous
    • Component indexing for faster startup
    • APT processor included in spring-context-indexer
    • Creates index in META-INF/spring.components
    • Nullability annotations in the entire codebase
    • @Nullable to indicate optionality at injection points
    • Data binding against immutable objects
    • Via constructor argument resolution and support for Kotlin / Lombok
    • WebClient as reactive alternative to RestTemplate
    34
    

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41. Spring Boot 2.0
    35
    

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42. Core themes
    • Upgrade to Java 8 and Spring Framework 5
    • Includes upgrades to all ecosystem projects based on those versions
    • Infrastructure upgrades
    • Jetty 9.4
    • Tomcat 8.5
    • Hibernate 5.2
    • Hikari connection pool (previously Tomcat)
    • Reactive web test support
    • OAuth 2.0 support moved to Spring Security
    • Tweaked defaults
    36
    

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43. Core themes
    • Actuator refactorings
    • Resources moved to /application/…
    • All secured by default
    • Micrometer support
    • Actuator customization API
    • To abstract over Spring MVC, Spring WebFlux, JAX-RS and JMX
    37
    

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44. Pruning
    • General deprecations present in 1.5
    • CRaSH project, Spring Loaded
    38
    

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45. Related talks
    10:45 - 11:45 — Going reactive with Spring Data
    Jens Schauder (Spring Data team member), Raum: Partenkirchen
    12:00 - 13:00 — The Beginner’s Guide to Spring Cloud
    Spencer Gibb (Spring Cloud co-lead), Raum: Partenkirchen
    39
    

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46. Thank you!
    Questions?
    / olivergierke
    Oliver Gierke ƀ ogierke@pivotal.io
    

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47. Resources
    41
    

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48. Resources
    Spring Framework 5 – Migration guide
    https://github.com/spring-projects/spring-framework/wiki/What's-New-in-Spring-Framework-5.x
    https://github.com/spring-projects/spring-framework/wiki/Upgrading-to-Spring-Framework-5.x
    Spring Framework 5 – FAQ
    https://github.com/spring-projects/spring-framework/wiki/Spring-Framework-5-FAQ
    42
    

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49. Resources
    Blog series on Reactive Programming
    https://spring.io/blog/2016/06/07/notes-on-reactive-programming-part-i-the-reactive-landscape
    Reactor – Project homepage
    https://projectreactor.io/
    43
    

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50. Resources
    Spring Boot 2.0 release notes
    https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-2.0-Release-Notes
    Spring Boot 1.5 -> 2.0 migration guide
    https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-2.0-Migration-Guide
    Micrometer documentation
    http://micrometer.io/docs
    Documentation of Spring Boot metrics
    https://docs.spring.io/spring-boot/docs/2.0.x/reference/htmlsingle/#production-ready-metrics
    Spring Boot 2.0 Actuators (blog post)
    https://spring.io/blog/2017/08/22/introducing-actuator-endpoints-in-spring-boot-2-0
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