Spring Boot 4 입문

Spring Boot is built on the Spring Framework to make production-ready apps faster to build. Think of it as a smart assistant that wires sensible defaults so you just write your logic.

Old Spring meant walls of XML and boilerplate config. Spring Boot kills that with convention over configuration and auto-configuration — less setup, more building.

Spring Boot's wins: standalone runnable JARs, embedded servers, smart auto-configuration, opinionated defaults, and production features like health checks and metrics.

An embedded server ships inside your JAR, so your app runs as a plain Java program — no external Tomcat to deploy to. Tomcat is default; Jetty and Undertow are options.

Auto-configuration reads your dependencies and sets things up for you. Add Spring Web and it wires an embedded server and dispatcher servlet — no boilerplate config needed.

Spring Initializr is the recommended way to start: pick your language, version, and dependencies, then download a ready-to-import Maven or Gradle project.

You'll need three things: a JDK (17+ recommended), an IDE like IntelliJ, Eclipse, or VS Code, and a build tool — Maven or Gradle.

Confirm your JDK is set up: run java -version in your terminal. Then try this tiny program to prove everything works.

Every Spring Boot app has a main class with @SpringBootApplication, which bundles @SpringBootConfiguration, @EnableAutoConfiguration, and @ComponentScan. Its main method is your entry point.

Nice work! You met Spring Boot, its auto-config and embedded servers, Spring Initializr, the tools you need, and the @SpringBootApplication annotation. Next: your first Hello World app.