XML中context:annotation-config和context:component-scan简述
<context:annotation-config/> 中文意思:<上下文:注解——配置/>
<context:component-scan base-package=" 扫描路劲" annotation-config=true/> 中文意思：<上下文：部件——扫描 基础——包=“扫描路径”
注解——配置=true/>(annotation-config=true是默认的配置可省略不写)
1.<context:annotation-config/>
<context:annotation-config/>配置的作用：是向Spring容器注册一次注入四个BeanPostProcessor
- AutowiredAnnotationBeanPostProcessor
- CommonAnnotationBeanPostProcessor
- PersistenceAnnotationBeanPostProcessor
- RequiredAnnotationBeanPostProcessor
AutowiredAnnotationBeanPostProcessor旧版注入方式<bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>作用是能使用@Autowired注解
CommonAnnotationBeanPostProcessor旧版注入方式<bean class="org.springframework.beans.factory.annotation.CommonAnnotationBeanPostProcessor"/>作用是能使用@Resource、@PostConstruct、@PreDestroy注解；
PersistenceAnnotationBeanPostProcessor旧版注入方式<bean class="org.springframework.beans.factory.annotation.PersistenceAnnotationBeanPostProcessor"/>作用是能使用@PersistenceContext注解;
RequiredAnnotationBeanPostProcessor旧版注入方式<bean class="org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor"/>作用是能使用@Required注解;
<context:annotation-config/>的总结即在XML文件中配置<context:annotation-config/>不需要再配置上面四个ben对象；
2.<context:component-scan base-package=" 扫描路劲" annotation-config=true/>
作用:具有<context:component-config/>注解的功能，还能对指定的package下扫描以及注册javabean