Why Spring Boot?
- Spring based applications have lot of configuration
- If we use Spring MVC, we need to configure ComponentScan, DispatcherServlet, ViewResolver, Web Jars, etc.
- World is moving towards micro-services and we don’t have time to configure 100 of them.
Goals of Spring Boot
- Quick start
- Opinionated
- Minimal code generation
Spring Boot Features
- Auto Configuration
- Spring Boot Starter Projects
- Actuator
- Embedded Server
Spring vs Spring MVC vs Spring Boot
Spring
Most important feature of Spring Framework is
- Dependency Injection
- IoC (Inversion of Control)
Spring MVC
It provides decoupled way of developing web applications.
- Dispatcher Servlet
- Model And View
- View Resolver
Spring Boot
Eliminates configuration needed by Spring and Spring MVC and auto-configures it
- No need for @ComponentScan. Default scan is provided.
- No need to configure Dispatcher Servlet
- No need to configure Data Source, Entity Manager Factory or Transaction Manager
Application Annotations
@SpringBootApplication
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan
public @interface SpringBootApplication {- SpringBootConfiguration - Enhance Spring’s configuration
- EnableAutoConfiguration - Auto configures application.properties
- ComponentScan - Turns on component scan inside the package
Auto Configuration
Spring Boot looks at
- Frameworks available on
CLASSPATH - Existing configuration of the application
Based on these, Spring Boot provides basic configuration needed to configure the app with these frameworks.
Implementation
- spring-boot-autoconfigure.jar
- Code written to configure frameworks and usage
- To get more details
-
Turn on Debug logging - Detailed report of Positive matches and Negative matches
logging.level.org.springframework: DEBUG -
Use Spring Boot Actuator - /application
-