Migrating to Spring Boot 2 and Webflux Gotchas migrating to Spring Boot 2 and Demo Migration from MVC to Webflux by @trevorgowing hosted by @travelstart 

Introduction 

Features of Spring and Boot ● Core Tech [IOC, events, resources, i18n, validation, data binding, type conversion, SpEL, AOP] ● Testing [Mocks, TestContext, MockMVC, WebTestClient] ● Data Access [TX, DAO, JDBC, ORM, XML] ● Integration [remoting, JMS, JCA, JMX, email, tasks, scheduling, cache] ● Web [MVC, WebFlux] ● Languages [Kotlin, Groovy] ● Stand-alone application ● Embed Tomcat, Jetty or Undertow ● Opinionated 'starter' dependencies ● Automatic configuration ● Production-ready features [metrics, health checks, externalized configuration] ● No code gen or XML 

A little about me 

What I have been doing recently? ● Developed 2 - 1.x ● Migrated 3 - 1.x -> 2.0 ○ 1 - Maven -> Gradle ● Migrated 1 - Traditional deployment (web.xml & application.xml) -> 2.0 (Java Config) ● Developed 0 - Webflux ● spring-boot-starter-web ● spring-boot-starter-json ● spring-boot-starter-amqp ● spring-boot-starter-security ● spring-boot-starter-data-jpa ● spring-boot-starter-actuator ● spring-boot-starter-data-redis ● spring-boot-starter-web-services 

History Time 

Spring Framework & Boot Release History ● 1.0 - March 2004 ● 2.0 - November 2006 ● 3.0 - June 2010 ● 4.0 - December 2013 ● 5.0 - September 2017 ● 5.0.7 - June 2018 - Latest ● 1.0 - April 2014 ● 1.1 - June 2014 ● 1.2 - December 2014 ● 1.3 - November 2015 ● 1.4 - July 2016 ● 1.5.1 - January 2017 ● 2.0 - March 2018 ● 2.0.3 - June 2018 - Latest 

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Dependency upgrades 1.2.x - > 1.3.x ● Spring Framework 4.1.9 -> 4.2.8 ● Spring Security 3.2.9 -> 4.0.4 

Spring Security 3.x -> 4.0 Gotchas ● Default filter paths renamed e.g. `/j_spring_security_logout` -> `/logout` ● Overriding default response headers no longer disables all unless explicitly specified ● Roles are automatically prefixed with “ROLE_” 

Dependency upgrades 1.3.x -> 1.4.x ● Elasticsearch 1.5.2 -> 2.4.5 ● Hibernate 4.3.11 -> 5.0.12 ● MongoDB 2.13.3 -> 3.2.2 ● Solr 4.10 -> 5.5 ● Spring Data Gosling SR5 -> Hopper SR11 ● Spring Framework 4.2.8 -> 4.3.9 (Requires Jackson 2.6+) ● Spring Security 4.0.4 -> 4.1.4 ● Tomcat 8.0.37 -> 8.5.15 (BIO Connector, Comet, JSR-77, InstanceListener removed) 

Hibernate 4.x -> 5.0 Gotchas ● ‘hibernate.id.new_generator_mappings’ property default changed to true. ○ `spring.jpa.hibernate.use-new-id-generator-mapping` defaults to false ● NamingStrategy split in two: ○ ImplicitNamingStrategy - used whenever a table or column is not explicitly named ○ PhysicalNamingStrategy - used to convert a "logical name" into a physical name ● I experienced this silently creating new tables, that were not previously explicitly named in combination with ddl-auto = update. 

Hibernate Id Generation Strategy for MySQL ● Default Id generation strategy changed from Identity to Table when using Auto generation strategy with MySQL. Table strategy not recommend. Hibernate 4.x Hibernate 5.x 

Dependency upgrades 1.4.x -> 1.5.x ● Gradle 1.2 -> 2.9 (Groovy 1.8 -> 2.3.2) ● Spring Data Hopper SR11 -> Ingalls SR13 ● Spring Security 4.14 -> 4.2.7 

Actuator 1.4.x -> 1.5.x Gotchas ● Sensitive endpoints are now secured by default (even without spring-security) ○ Override with: `management.security.enabled=false` ● Default role changed from ‘ADMIN’ to ‘ACTUATOR’ ○ override with: `management.security.roles={ROLE}` 

2 . 0 

Dependency upgrades 1.5 -> 2.0 ● Flyway 3.2.1 -> 5.0.7 (Java 8, Maven 3 & Gradle 3 Baselines, Java 9 & Cockroach Support) ● Gradle 2.9 -> 4.x ● Java 8 baseline & Java 9 support ● Hibernate 5.0.12 -> 5.2.17 ● Mockito 1.10.19 -> 2.15.0 (argThat moved to org.mockito.hamcrest.MockitoHamcrest) ● Spring Data Ingalls SR13 -> Kay SR8 ○ (Java 8, Framework 5, Reactive [Mongo, Redis, Couch, Cassandra], Java 9 Support) ● Spring Framework and Security 4.x.x -> 5.0.x ● Thymeleaf 2.1.6 -> 3.0.9 (https://www.thymeleaf.org/doc/articles/thymeleaf3migration.html) 

Changes and Gotchas ● Default JDBC connection pool: Tomcat - > Hikari ● Gradle plugin rewritten ○ Spring Boot & Dependency Management plugins separated ○ BootJar & BootWar tasks replace BootRepackage and extend Java Jar & War tasks ○ BootRun extends JavaExec ● Properties ○ A number of properties have been renamed, replaced or re-namespaced ○ Relaxed binding has been tightened ○ Org.springframework.boot.bind package has been removed & replaced by new binding api (see https://github.com/spring-projects/spring-boot/wiki/Relaxed-Binding-2.0) 

Changes and Gotchas continued... ● Web starters e.g. thymeleaf no longer transitively depend on starter-web ● Jackson JSR-310 dates now written as ISO8601 strings by default ○ Restore previous behaviour ‘spring.jackson.serialization.write-dates-as-timestamps=true’ ● HTTP suffix pattern matching is disabled by default ○ GET /proj/spring-boot.json will no longer map to @GetMapping(“/proj/spring-boot) ● ‘spring.jpa.hibernate.use-new-id-generator-mappings’ now defaults to true ● Data repository method signature changes ○ e.g. T findOne(T id) -> Optional findById(T id) 

New Features ● HTTP/2 Support (Web Server specific) ● Kotlin 1.2 Support ● Thymeleaf javax.time support ● Jackson & Java 8 data types packaged in ‘spring-boot-starter-json’ 

Actuator 1.5 -> 2.0 ● Technology agnostic: MVC or Webflux ● Request & Response structure changes ● Read/Write Model -> CRUD Model ● Config with `endpoints.{name}.enabled` & `endpoints.{name}.sensitive` properties -> `management.endpoints.web.exposure.include` ● Custom security -> Spring Security ● Mapped under `/` -> Mapped under `/actuator` ● Custom metrics -> Micrometer.io 

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A little about Reactive 

Reactive Streams Specification 

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Project Reactor 

Spring Web - MVC and/or Webflux 

Enough talking, demo time! https://github.com/trevorgowing/spring-boot-migration 

But is it faster? 

2500 Concurrent Users 

5000 Concurrent Users 

10000 Concurrent Users 

References - Migration ● https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-2.0-Migrati on-Guide ● https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-2.0-Releas e-Notes ● https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-1.5-Releas e-Notes ● https://vladmihalcea.com/why-should-not-use-the-auto-jpa-generationtype- with-mysql-and-hibernate/ ● https://vladmihalcea.com/why-you-should-never-use-the-table-identifier-gen erator-with-jpa-and-hibernate/ 

References - Spring Boot 2 ● https://docs.spring.io/spring-boot/docs/current/reference/html/ ● https://www.brighttalk.com/webcast/14893/304441/introducing-spring-bo ot-2-0 ● https://github.com/philwebb/spring-boot-2-webinar ● http://www.baeldung.com/new-spring-boot-2 ● http://www.baeldung.com/spring-boot-actuators ● http://www.baeldung.com/spring-security-5-reactive 

References - Reactive & Reactor ● https://www.reactivemanifesto.org/ ● http://www.reactive-streams.org/ ● https://projectreactor.io/ ● https://spring.io/blog/2016/06/07/notes-on-reactive-programming-part-i-th e-reactive-landscape ● https://spring.io/blog/2016/06/13/notes-on-reactive-programming-part-ii-wr iting-some-code ● https://spring.io/blog/2016/07/20/notes-on-reactive-programming-part-iii-a- simple-http-server-application ● https://spring.io/blog/2016/04/19/understanding-reactive-types 

References - Webflux ● https://docs.spring.io/spring/docs/current/spring-framework-reference/we b-reactive.html ● http://www.baeldung.com/spring-5 ● http://www.baeldung.com/spring-security-5-reactive ● https://www.journaldev.com/20763/spring-webflux-reactive-programming ● https://acuriouscoder.net/spring-webflux-annotation-based/ ● http://javasampleapproach.com/spring-framework/spring-webflux/springbo ot-webflux-annotation-based-programming-model ● https://dzone.com/articles/annotated-controllers-spring-webwebflux-and-te stin 

References - Other ● https://medium.com/@the.raj.saxena/springboot-2-performance-servlet-sta ck-vs-webflux-reactive-stack-528ad5e9dadc ● https://www.romaniancoder.com/book-review-clean-architecture-by-robert- c-martin/ ● http://www.sportingnews.com/au/football/news/2018-fifa-world-cup-who-i s-off-to-russia-who-missed-out/13kxz8c09i2s516e8v0esdl6mf