Spring Boot

• Make it easy to start a Spring project
• Minimize the amount of manual configuration
• Provides an embedded HTTP server (tomcat, jetty, undertow, ...)
• But you can also deploy the war file to an external server

Spring Initializr

• Spring Initializr creates a spring project boilerplate
• https://start.spring.io/
• jar: do not use src/main/webapp folder
• war: use src/main/webapp

Project Structure

.
├── HELP.md
├── pom.xml
├── mvnw         # embedded maven cmdline, run maven commands with no need to have maven installed (safe to remove) ./mvnw clean compile test
├── mvnw.cmd     # same as mvnw, but for windows
├── .mvn
│   └── wrapper
│       └── maven-wrapper.properties # maven properties
├── src/
│   ├── main/
│   │   ├── java/                        # source code
│   │   │   └── com/
│   │   └── resources/
│   │       ├── static/                 # html, css, js, images, etc
│   │       ├── templates/              #
│   │       └── application.properties  # properties and config file
│   └── test/
│       └── java/                        # unit tests
│           └── com/
└── target/
    ├── classes/
    │   ├── application.properties
    │   └── com/
    └── test-classes/
        └── com/

Application

• @SpringBootApplication
• @EnableAutoConfiguration: auto-configuration support
• @ComponentScan: scan components to register beans

• @Configuration: register extra beans

• SpringApplication.run(DemoApplication.class, args)

• Creates the application context and register all beans

• Starts the embedded server

• Place your Application.java in the root package

• Implicitly defines the base search package (component scanning)
• You can also explicitly base package with scanBasePackages parameter

package com.hvitoi.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication // @SpringBootApplication(scanBasePackages={"com.hvitoi.demo", "org.acme.iot.utils"})
public class DemoApplication {

  public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
  }
}