feat(controller): 添加Demo控制器并更新依赖配置

- 创建了DemoController类，提供/hello接口返回"Hello World!"
- 在pom.xml中添加spring-boot-starter核心依赖
- 将spring-boot-starter-webmvc替换为spring-boot-starter-web
- 将spring-boot-starter-webmvc-test替换为spring-boot-starter-test
- 添加spring-boot-starter-actuator监控组件
- 注释掉数据库相关依赖以简化项目配置

pom.xml

@@ -30,13 +30,17 @@
 		<java.version>17</java.version>
 	</properties>
 	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter</artifactId>
+		</dependency>
 <!--		<dependency>-->
 <!--			<groupId>org.springframework.boot</groupId>-->
 <!--			<artifactId>spring-boot-starter-jdbc</artifactId>-->
 <!--		</dependency>-->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
-			<artifactId>spring-boot-starter-webmvc</artifactId>
+			<artifactId>spring-boot-starter-web</artifactId>
 		</dependency>
 <!--		<dependency>-->
 <!--			<groupId>org.mybatis.spring.boot</groupId>-->
@@ -56,10 +60,14 @@
 <!--		</dependency>-->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
-			<artifactId>spring-boot-starter-webmvc-test</artifactId>
+			<artifactId>spring-boot-starter-test</artifactId>
 			<scope>test</scope>
 		</dependency>
-<!--		<dependency>-->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-actuator</artifactId>
+		</dependency>
+		<!--		<dependency>-->
 <!--			<groupId>org.mybatis.spring.boot</groupId>-->
 <!--			<artifactId>mybatis-spring-boot-starter-test</artifactId>-->
 <!--			<version>4.0.1</version>-->

src/main/java/com/example/demo/controller/DemoController.java

@@ -0,0 +1,14 @@
+package com.example.demo.controller;
+
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController()
+@RequestMapping("/demo")
+public class DemoController {
+
+    @RequestMapping("/hello")
+    public String demo() {
+        return "Hello World!";
+    }
+}