Spring <context:component-scan base-package=""/> 与 <context:annotation-config/>的区别

<?xmlversion="1.0"encoding="UTF-8"?>
<beansxmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:jpa="http://www.springframework.org/schema/data/jpa"
xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/tx/spring-util-3.2.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd"
default-lazy-init="true">

<!-- 开启注解服务 -->
<context:annotation-config/>
<beanid="animals"class="org.spring.test2.Animals"></bean>
</beans>

public class Animals {
//@Autowired与@Resource功能相似，都是从spring获取实例
@Resource
@Qualifier("cat")
private Animalanimal;
public void arouse(){
animal.arouse();
}
}

public interface Animal{
public void arouse();
}

/**
* 当前对象注入到spring容器中
*/
@Service
public class Cat implements Animal{
//给song赋值
@Value("CAT...SONG")
private String song;
@Override
public void arouse() {
System.out.println("Cat's song is ="+song);
}
}

/**
* 当前对象注入到spring容器中
*/
@Service
public class Dog implements Animal{
//给song赋值
@Value("DOG...SONG")
private Stringsong;
@Override
public void arouse() {
System.out.println("Dog's song is ="+song);
}
}

Exception in thread "main"org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'animals': Injection of resource dependencies failed; nested exception isorg.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.spring.test2.Animal] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@javax.annotation.Resource(shareable=true, mappedName=, description=, name=, type=class java.lang.Object, authenticationType=CONTAINER, lookup=), @org.springframework.beans.factory.annotation.Qualifier(value=cat)}
at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues(CommonAnnotationBeanPostProcessor.java:306)
ba56
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1116)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1117)
at org.spring.test2.Test.main(Test.java:10)