Spring Boot Tutorial: Project Creation, Configuration, and Customization

The article introduces Spring Boot as a solution to the heavy configuration required by Spring and Spring MVC, highlighting its core capabilities: independent runnable JARs, embedded servlet containers, starter dependencies, automatic configuration, production‑ready monitoring, and elimination of XML.

1. Independent Spring project execution

Spring Boot applications can be launched directly with java -jar xx.jar , simplifying deployment.

2. Embedded servlet container

It embeds Tomcat, allowing execution without a WAR file.

3. Starter POMs to simplify Maven configuration

Starters bundle common dependencies, reducing the need to list each one manually.

4. Automatic configuration, production‑grade monitoring, and no XML

The article then walks through creating a Spring Boot project using IntelliJ IDEA, showing screenshots of the Spring Initializr wizard, project metadata entry, dependency selection (Web), and final project naming.

After project generation, the generated entry class Test19SpringBoot2Application is shown, annotated with @SpringBootApplication . Adding @RestController and a simple request mapping creates a hello endpoint:

@RestController
@SpringBootApplication
public class Test19SpringBoot2Application {
    public static void main(String[] args) {
        SpringApplication.run(Test19SpringBoot2Application.class, args);
    }
    @RequestMapping(value = "/", produces = "text/plain;charset=UTF-8")
    String index() {
        return "Hello Spring Boot!";
    }
}

The article explains how to run the application from IntelliJ and access the endpoint via a browser.

Entry Class and @SpringBootApplication Annotation

The annotation combines @SpringBootConfiguration , @EnableAutoConfiguration , and @ComponentScan . If not using @SpringBootApplication , the three annotations can be applied individually.

Disabling Specific Auto‑Configuration

Specific auto‑configurations can be excluded, e.g., @SpringBootApplication(exclude = DataSourceAutoConfiguration.class) .

Customizing the Banner

Spring Boot prints a banner on startup. To change it, create src/main/resources/banner.txt with ASCII art generated from an online tool. To disable the banner, modify the main method:

public static void main(String[] args) {
    SpringApplicationBuilder builder = new SpringApplicationBuilder(Test19SpringBoot2Application.class);
    // Turn banner off
    builder.bannerMode(Banner.Mode.OFF).run(args);
}

Configuration Files

Spring Boot uses application.properties or application.yml under src/main/resources . Examples include changing the server port and context path:

server.context-path=/helloboot
server.port=8081

Properties can be injected with @Value :

@Value("${book.author}")
private String bookAuthor;
@Value("${book.name}")
private String bookName;
@Value("${book.pinyin}")
private String bookPinYin;

The controller then returns these values in the response.

Type‑Safe Configuration

Instead of injecting many individual properties, a bean can be bound to a properties file using @ConfigurationProperties . The article shows a BookBean class bound to book.properties and demonstrates autowiring it in a controller to expose the data via /book .

Logging Configuration

Spring Boot defaults to Logback. Logging output location and level can be set in application.properties :

logging.file=/home/sang/workspace/log.log
logging.level.org.springframework.web=debug

Profile Configuration

Environment‑specific settings are placed in application‑dev.properties and application‑prod.properties . The active profile is chosen with spring.profiles.active in the main application.properties . Switching the profile changes the server port accordingly.

Finally, a download link to the complete example project is provided.