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。”