server:
 url: http://localhost 
 myapp:
  name: MyApplication
  threadCount: 4
...

server.url=http://localhost
server.myapp.name=MyApplication
server.myapp.threadCount=4
...

server:
 url: http://myapp.org 
 app:
  name: MyApplication
  threadCount: 10
  users: 
   - Jacob
   - James

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;

import java.util.ArrayList;
import java.util.List;

/**
 * @program: simple-demo
 * @description: 映射屬性 (server節(jié)點(diǎn))
 * @author: CaoTing
 * @date: 2019/6/3
 **/
@Data
@ConfigurationProperties("server")
public class ServerProperties {
 
 private String url;
 
 private final App app = new App();
 
 public App getApp() {
  return app;
 }
 
 public static class App {
 
  private String name;
  private String threadCount;
  private List<String> users = new ArrayList<>();
  // TODO getter and setter
 }
 
}

import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Configuration;

/**
 * @program: simple-demo
 * @description: 注冊(cè)所有映射屬性類 { }中用逗號(hào)分隔即可注冊(cè)多個(gè)屬性類
 * @author: CaoTing
 * @date: 2019/6/3
 **/
@Configuration
@EnableConfigurationProperties({ServerProperties.class})
public class ApplicationConfig {
}

import com.caotinging.ymldemo.application.YmlValueApplication;
import com.caotinging.ymldemo.config.ServerProperties;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

/**
 * @program: simple-demo
 * @description: 單元測(cè)試類
 * @author: CaoTing
 * @date: 2019/6/3
 **/
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = YmlValueApplication.class)
public class AppYmlValueTest {

 @Autowired
 private ServerProperties config;

 @Test
 public void printConfigs() {
   System.out.println(this.config.getUrl());
   System.out.println(this.config.getApp().getName());
   System.out.println(this.config.getApp().getThreadCount());
   System.out.println(this.config.getApp().getUsers());
 }
}