偶尔发现的

我开启注解扫描发现StudentDao居然自动指向StudentDaoImpl

package com.san.test.demo3;

import org.springframework.stereotype.Component;

@Component
public class StudentDaoImpl implements StudentDao {
   @Override
   public void find() {
       System.out.println("学生查询");
   }

   @Override
   public void save() {
       System.out.println("学生保存");
   }

   @Override
   public void update() {
       System.out.println("学生修改");
   }

   @Override
   public void delete() {
       System.out.println("学生删除");
   }
}

package com.san.test.demo3;

public interface StudentDao {
   public void find();
   public void save();
   public void update();
   public void delete();
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns:context="http://www.springframework.org/schema/context"
      xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd ">

   <context:component-scan base-package="com.san.test.demo3"/>


   <!---->
  <!-- <bean id="studentDao" class="com.san.test.demo3.StudentDaoImpl"></bean>
   &lt;!&ndash;前置通知类型&ndash;&gt;
   <bean id="myBeforeAdvice" class="com.san.test.demo3.MyBeforeAdvice"/>

   &lt;!&ndash;Spring的Aop产生代理对象&ndash;&gt;
   <bean id="studentDaoProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
       &lt;!&ndash;配置目标类&ndash;&gt;
       <property name="target" ref="studentDao"/>
       &lt;!&ndash;实现接口&ndash;&gt;
       <property name="proxyInterfaces" value="com.san.test.demo3.StudentDao"/>
       &lt;!&ndash;采用拦截器的名称&ndash;&gt;
       <property name="interceptorNames" value="myBeforeAdvice"/>
   </bean>-->
</beans>

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:Application.xml")
public class SpringTest {
   /*@Resource(name = "studentDao")*/
   @Autowired
   private StudentDao studentDao;

   @Test
   public void demo1(){
       studentDao.delete();
   }
}

这是为什么呢，我的application.xml就写了开启扫描注解，但却能自动生成实现类的实例化