Introduction to Spring Boot
- 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