Make use of new GetMapping and PostMapping annotations

Closes gh-5277

spring-boot-samples/spring-boot-sample-war/src/main/java/sample/war/MyController.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,13 +16,13 @@
 
 package sample.war;
 
-import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
 
 @RestController
 public class MyController {
 
-	@RequestMapping("/")
+	@GetMapping("/")
 	public String hello() {
 		return "Hello World!";
 	}