一、配置文件：
server.port=9123

二、配置类：

package cn.edu.tju.config;import com.mysql.fabric.Server;
import org.springframework.boot.autoconfigure.web.ServerProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
@EnableConfigurationProperties(ServerProperties.class)
public class MyConfig {@Bean("portBean")public String getPort(ServerProperties serverProperties){return "hello " + serverProperties.getPort();}
}

三、测试

package cn.edu.tju;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;@SpringBootApplication
public class Start {public static void main(String[] args) {ConfigurableApplicationContext context = SpringApplication.run(Start.class, args);String result = context.getBean("portBean", String.class);System.out.println(result);}
}