[Back end] Spring Boot @Autowired null 에러

Thread를 통해 Service를 호출하려고 하면 @Autowired null 관련 에러가 발생한다. Thread 클래스가 Bean으로 등록된 클래스가 아니어서 IOC Container를 통해 자동 주입되지 않는다. @Autowired는 Bean으로 등록된 클래스에서만 사용 가능하다.

이럴 때는 Bean을 수동으로 주입하면 해결 가능하다.

ApplicationContextProvider

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class ApplicationContextProvider implements ApplicationContextAware {

  private static ApplicationContext applicationContext;

  @Override
  public void setApplicationContext(ApplicationContext ctx) throws BeansException {
    applicationContext = ctx;
  }

  public static ApplicationContext getApplicationContext() {
    return applicationContext;
  }
}

BeanUtils

import org.springframework.context.ApplicationContext;

import com.skcc.kw.common.ApplicationContextProvider;

public class BeanUtils {
  public static Object getBean(String bean) {
    ApplicationContext applicationContext = ApplicationContextProvider.getApplicationContext();
    return applicationContext.getBean(bean);
  }
}

 

Example

@Service
public class UserService {
  ...
}

public class UserThread implements Runnable {

  // Bean 주입
  UserService userService = (UserService) BeanUtils.getBean("userService");
  
  ...
  
}