섹션 8-3 [외부 설정을 이용한 자동 구성] @Value와 PropertySourcesPlaceholderConfigurer

@Value와 PropertySourcesPlaceholderConfigurer

@MyAutoConfiguration  
@ConditionalMyOnClass("org.apache.catalina.startup.Tomcat")  
public class TomcatWebServerConfig {  
  
    @Value("${contextPath}")  
    String contextPath;  
  
    @Bean("tomcatWebServerFactory")  
    public ServletWebServerFactory servletWebServerFactory() {  
        TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();  
        factory.setContextPath(this.contextPath);  
        return factory;  
    }  
}

application.properties의 환경변수를 필드로 주입받기 위해서는 @Value 애노테이션을 사용하면 주입받을 수 있습니다. 다만 위 설정만 하고 Application run을 하면 오류가 발생합니다. 왜냐하면 빈 생성수 후처리작읍을 해야할 bean을 설정해주지 않았기 때문에 아무리 @Value애노테이션을 설정하였다 하더라도 application.properties의 설정한 값이 주입되지 않고 @Value애노테이션에 설정한 값이 그대로 출력됩니다.

 

@MyAutoConfiguration  
public class PropertyPlaceholderConfig {  
  
    @Bean  
    PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {  
        return new PropertySourcesPlaceholderConfigurer();  
    }  
  
}

따라서 자동구성정보의 후처리를 담당할 PropertySourcesPlaceholderConfigurer bean을 등록해 줍니다.

 

com.tobyspring.config.MyAutoConfiguration.imports

com.tobyspring.config.autoconfig.PropertyPlaceholderConfig

자동 구성정보를 추가하기때문에 Spring이 인지할 수 있도록 imports파일에 해당 PropertySourcesPlaceholderConfigurer를 등록해 줍니다.