开始...

1、首先创建一个maven工程，引入springboot依赖

<dependencies>
        <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
         <!--热部署-->
        <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <version>2.0.5.RELEASE</version>
        </dependency>
</dependencies>

2、编写启动springboot的启动类

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

3、编写一个可访问的Controller，该类可以获取application.yml文件中的变量
application.yml内容

server:
  port: 9001
spring:
  profiles:
    active: linux

@Controller
public class HelloController {
    @Autowired
    ApplicationContext applicationContext;
    @GetMapping(value = "/hello")
    @ResponseBody
    public String hello(){
        return applicationContext.getEnvironment().getProperty("server.port");
    }
}

4、在浏览器输入地址http://localhost:9001/hello
页面显示9001

...结束