spring配置扫描多个包 spring配置扫描多个包问题解析

<!-- 自动扫描该包，使 SpringMVC 为包下用了@controller注解的类是控制器 --> 
<context:component-scan base-package="com.weixiao.ssmcleardb.controller" /> 
<context:component-scan base-package="com.weixiao.listener" /> 

package com.weixiao.listener;
import javax.servlet.ServletContext;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.stereotype.Component;
import org.springframework.web.context.ServletContextAware;
@Component("StartupListener") 
public class StartupListener implements ApplicationContextAware, ServletContextAware, InitializingBean, 
    ApplicationListener<ContextRefreshedEvent> {
	protected Logger logger = LogManager.getLogger(getClass());
	@Override 
	  public void setApplicationContext(ApplicationContext ctx) throws BeansException {
		logger.info("\r\n\r\n\r\n\r\n1 => StartupListener.setApplicationContext");
	}
	@Override 
	  public void setServletContext(ServletContext context) {
		logger.info("\r\n\r\n\r\n\r\n2 => StartupListener.setServletContext");
	}
	@Override 
	  public void afterPropertiesSet() throws Exception {
		logger.info("\r\n\r\n\r\n\r\n3 => StartupListener.afterPropertiesSet");
	}
	@Override 
	  public void onApplicationEvent(ContextRefreshedEvent event) {
		logger.info("\r\n\r\n\r\n\r\n4.1 => MyApplicationListener.onApplicationEvent");
		logger.info("\r\n\r\n\r\n\r\n4.1 => " + event.getApplicationContext().getParent());
		logger.info("\r\n\r\n\r\n\r\n4.1 => " + event.getApplicationContext().getDisplayName());
		if (event.getApplicationContext().getParent() == null) {
			logger.info("\r\n\r\n\r\n\r\n4.2 => MyApplicationListener.onApplicationEvent");
		} else{
			logger.info("\r\n\r\n\r\n\r\n4.4 => " + event.getApplicationContext().getParent().getDisplayName());
		}
		if (event.getApplicationContext().getDisplayName().equals("Root WebApplicationContext")){
			logger.info("\r\n\r\n\r\n\r\n4.3 => MyApplicationListener.onApplicationEvent");
		}
	}
}

Spring 2.5引入了更多典型化注解(stereotype annotations)： @Component、@Service和 @Controller。@Component是所有受Spring管理组件的通用形式；而@Repository、@Service和 @Controller则是@Component的细化，用来表示更具体的用例(例如，分别对应了持久化层、服务层和表现层)。也就是说，你能用@Component来注解你的组件类，但如果用@Repository、@Service 或@Controller来注解它们，你的类也许能更好地被工具处理，或与切面进行关联。例如，这些典型化注解可以成为理想的切入点目标。当然，在Spring Framework以后的版本中， @Repository、@Service和 @Controller也许还能携带更多语义。如此一来，如果你正在考虑服务层中是该用@Component还是@Service，那@Service显然是更好的选择。同样的，就像前面说的那样， @Repository已经能在持久化层中进行异常转换时被作为标记使用了。”