增加helloController

src/main/java/com/matrix/demo/controller/HelloController.java

+package com.matrix.demo.controller;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * HelloController.
+ *
+ * @author Matrix <xhyrzldf@gmail.com>
+ * @since 2020/9/18 at 11:29 上午
+ */
+@RestController
+public class HelloController {
+
+    @GetMapping("/hello")
+    public ResponseEntity HelloWorld(){
+        return ResponseEntity.ok("Hello World!");
+    }
+}