Spring Boot 擷取配置檔案application.properties的屬性值

1、實作CommandLineRunner接口，（org.springframework.boot.CommandLineRunner）

2、添加類注解：@Configuration，（org.springframework.context.annotation.Configuration）

3、通過@Autowired自動裝載接口ApplicationContext，（org.springframework.context.ApplicationContext）

4、在接口函數run中通過ApplicationContext擷取Environment，（Environment environment = applicationContext.getEnvironment();）

5、通過Environment擷取屬性值：environment.getProperty("spring.datasource.url")

代碼示例（擷取配置檔案application.properties中server.port的值）：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;

@Configuration
public class MyConfiguration implements CommandLineRunner {

	@Autowired
	ApplicationContext applicationContext;

	@Override
	public void run(String... args) throws Exception {
		Environment environment = applicationContext.getEnvironment();
		String serverPort = environment.getProperty("server.port");
		System.out.println("value of server.port is " + serverPort);
	}

}
           

啟動spring boot即會進入到run中