Spring Boot makes it easier to create Spring-based applications and services. It removes boilerplate configuration and provides opinionated defaults to simplify setup of common Spring and related technologies. Some benefits include embedded servers reducing complexity, autoconfiguration that wires components together, and starter dependencies that add common libraries. Spring Boot helps create production-ready Spring applications with less effort.

1. Introduction to Spring Boot
Trey Howard
@thoward333
thoward333
https://www.linkedin.com/in/treyhoward

2. Why Spring?
● Dependency Injection
○ Promotes more maintainable code
○ Promotes testable code
● First class support for all layers of the stack
○ Tomcat, Jetty, Undertow
○ View: JSP, Velocity, Freemarker, JSON, REST/SOAP
○ Repository: Hibernate, JPA, JDBC
○ Database: RDBMS and NoSQL
○ Testing: JUnit, Mockito, Spring Test

3. Why Spring Boot?
● More choices = More complexity
● Inconsistent dependency versions
● @Autoconfiguration

4. ● Maven or Gradle
● Convention over Configuration
○ application.properties (and -profile.properties)
○ src/main/resources: /templates, /static
● Harmonizes library versions (Spring and non-Spring)
○ Version of Spring Boot is the only thing you have to manage
● Opinionated
○ Embedded Tomcat for MVC app, 1-line config change to Jetty, Undertow or none
○ Detects Spring Security on classpath and wires up sensible defaults
■ You don’t want Spring Security? 1-line change to turn off
■ Don’t like the OOTB settings? Extend this class
● spring-boot-starter-actuator
Benefits of Spring Boot

5. Creating a Spring Boot Project
● Create a seed project using web, IDE, or CLI
○ http://start.spring.io/
○ Download Spring Source STS (Latest 3.8.1)
○ Install CLI (Latest 1.4.0)
■ Creates, runs & more
● Secret sauce: Parent pom.xml
● Include spring-boot-starter-* modules

6. Spring Boot CLI
Entire project is single file: hello.groovy
@RestController
class WebApplication {
@RequestMapping("/")
String home() {
"Hello World!"
}
}
spring run hello.groovy

7. Live Demo - Create New Boot Project
http://start.spring.io/

8. Demo - REST API
● Basic REST API
● Hard-coded repository class for now

9. Demo - JDBC
● spring-boot-starter-jdbc
● Uses JdbcTemplate to query database

10. Demo - JPA
● spring-boot-starter-data-jpa
● Uses CrudRepository to query database
● Notice it’s an interface, not a class
● Method names drive fields that are queried
○ findByEmail(String email) will query db with ‘...where email = ?’

11. Demo - JPA Data REST
● spring-boot-starter-data-jpa & spring-boot-starter-data-rest
● No @Controller
● Because we have included spring-boot-starter-data-rest, Spring creates
REST endpoints for all @Entity classes

12. Spring Security with Spring Boot
● spring-boot-starter-security
● Add @EnableWebSecurity

13. OAuth2 with Spring Boot
● Add @EnableAuthorizationServer
○ Creates /oath/token endpoint that creates OAuth tokens
● Add @EnableResourceServer
○ Receives OAuth token via HTTP Header
● Demo
○ curl localhost:8080/oauth/token -d scope=read -d grant_type=password -d
username=springboot -d password=workshop -u myid:mysecret
○ curl localhost:8080 -H “Authorization: Bearer <access_token>”

14. Goodies in Spring Web (Boot 1.4.0)
● spring-devtools: Dual Classpath and Live Reload
● URL Binding annotations:
○ @GetMapping, @PostMapping, etc (@RequestMapping pre-1.4.0)
○ @RestControllerAdvice (@ControllerAdvice + @ResponseBody pre-1.4.0)
○ @SpringBootTest, @WebMvcTest, @AutoConfigureMockMvc, @MockBean, @SpyBean
● HTTP Options, Head are now supported
● RestTemplate setDefaultUriVariables
● @ConfigurationProperties / @EnableConfigurationProperties
○ Strongly typed properties backed by property files
○ Optional metadata for IDE, extra devtools module will auto-generate metadata

15. Goodies in Spring Security (Boot 1.4.0)
● Can access Principal in SpEL expression in Repository layer @Query:
@Query(“select * from foo where owner = ?#{principal.userId}”)
public Foo getFooForCurrentUser() ...
● mvcMatcher - alternative to antMatcher, has suffix vulnerability /foo vs /foo/
● @EnableAuthorizationServer / @EnableResourceServer

16. Resources
● Spring Boot Reference Guide:
http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/
○ Installing Spring Boot CLI:
http://docs.spring.io/spring-boot/docs/current/reference/html/getting-started-installing-spring-bo
ot.html#getting-started-installing-the-cli
● Initializr: http://start.spring.io/
● What’s new in Spring Boot 1.4:
https://spring.io/blog/2016/07/28/spring-boot-1-4-released