IOC容器的注入例题

public class ClassServiceImp implements ClassServiceInter {

    @Autowired
    private ClassDAOInter cdao;

那么cdao能被成功注入吗？如果不能，怎么修改？

答案：不能，因为ClassServiceImp不在IOC容器中，所以不能通过注解的方式来注入bean

第一种方法是在ClassServiceImp上添加注解@Service，将这个类注入ioc容器。

第二种方法是通过

private  ClassDAOInter cdao1 = IocUtil.getInstance().getIoc().getBean(ClassDAOInter.class);

来先获取IOC容器的实例，再手动从容器中拿出ClassDaoInter实例注入。

IocUtil：

public class IocUtil {

    private static final IocUtil INSTANCE =new IocUtil();

    private static ClassPathXmlApplicationContext ioc;

    private IocUtil(){
        System.out.println("\t启动IoC容器");
        ioc =new ClassPathXmlApplicationContext("spring-config.xml");
    }

    public static IocUtil getInstance(){
        return INSTANCE;
    }

    public ClassPathXmlApplicationContext getIoc(){
        return ioc;
    }
}

spring-config.xml：

<?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"
       xmlns:mybatis="http://mybatis.org/schema/mybatis-spring" xmlns:aop="http://www.springframework.org/schema/aop"
       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
           http://mybatis.org/schema/mybatis-spring
           http://mybatis.org/schema/mybatis-spring.xsd http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd">

    <!-- 自动扫描注解 -->
    <context:component-scan base-package="包路径"/>
    <!--开启 AOP 注解开关-->
    <aop:aspectj-autoproxy/>
  
</beans>