实现一个SpringBoot程序

1. 创建maven工程，导入依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <version>2.2.2.RELEASE</version>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <version>2.2.2.RELEASE</version>
</dependency>

2. 创建启动类：
   Application.java:

package hello;

import java.util.Arrays;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class Application {

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

  @Bean
  public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
    return args -> {

      System.out.println("Let's inspect the beans provided by Spring Boot:");

      String[] beanNames = ctx.getBeanDefinitionNames();
      Arrays.sort(beanNames);
      for (String beanName : beanNames) {
        System.out.println(beanName);
      }

    };
  }
}

3. 创建HelloController:

package hello;

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

@RestController
public class HelloController {

  @RequestMapping("/")
  public String index() {
    return "Greetings from Spring Boot!";
  }

}

4. 测试：启动程序并访问http://localhost:8080/

内容参考：https://spring.io/guides/gs/spring-boot/