Generate your WAR-ready project at start.spring.io (remember to select WAR packaging), add the five lines of controller code above, and run mvnw package . Your Hello World WAR will be waiting in the target/ folder in less time than it took to read this article.
Whether you download a sample, generate one from start.spring.io, or build it manually with a single controller, having a reliable WAR file in your toolkit ensures you’re ready for any deployment scenario—even if that scenario still runs on Tomcat 9 in a data center built a decade ago. spring boot hello world war file download
@GetMapping("/") public String hello() return "Hello World from Spring Boot WAR!"; Generate your WAR-ready project at start
@RestController public class HelloController generate one from start.spring.io
package com.example.demo; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController;