新建一个maven工程

引入依赖项

<modelVersion>4.0.0</modelVersion>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.11.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<groupId>org.example</groupId>
<artifactId>Springboot</artifactId>
<version>1.0-SNAPSHOT</version>

<properties>
    <maven.compiler.source>8</maven.compiler.source>
    <maven.compiler.target>8</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <executions>
                <execution>
                    <goals>
                        <goal>repackage</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <mainClass>org.example.Application</mainClass>
            </configuration>
        </plugin>
    </plugins>
</build>

SpringBoot启动类

package org.example;

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

@SpringBootApplication
public class Application {

  public static void main(String[] args) throws Exception {
    SpringApplication.run(Application.class, args);
  }
}

编写controller类

package org.example.control;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {
    @RequestMapping(value = "/hello")
    public String hello(){

        return "hello world";
    }
}

通过浏览器访问 http://localhost:8080/hello

github代码：GitHub - JJJ2018/springboot_helloworld_sample: springboot helloworld sample