使用IDE创建一个Maven项目（不使用骨架）。

配置pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>fun.hara</groupId>
    <artifactId>demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    
    <!-- 1、配置父项目为 Spring Boot -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.0.RELEASE</version>
    </parent>
   
    <dependencies>
        <!-- 2、添加 Web 相关依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
    
    <build>
        <plugins>
            <!-- 3、指定 JDK 版本 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

创建BootApplication类和HelloController类

package fun.hara.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class BootApplication {
    public static void main(String [] args){
        SpringApplication.run(BootApplication.class, args);
        System.out.println("项目已启动...");
    }
}

package fun.hara.demo.hello.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

@Controller
public class HelloController {
    @RequestMapping("/hello")
    public void hello(HttpServletResponse response) throws Exception{
        PrintWriter writer = response.getWriter();
        writer.println("hello world");
        writer.close();
    }
}

启动项目即可访问。