【Spring笔记】IOC容器—Bean管理XML方式（注入外部Bean）

UserService.class

用 set 方法获得注入

public class UserService {
    //创建UserDao类型属性，生成set方法
    private UserDao userDao;

    public UserDao getUserDao() {
        return userDao;
    }

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

    public void add(){
        System.out.println("service add ....");
        userDao.update();
    }
}

UserDao.class

public interface UserDao  {
    public void update();
}

UserDaoImpl.class

public class UserDaoImpl implements UserDao{

    @Override
    public void update() {
        System.out.println("dao update ....");
    }
}

XML（外部注入）

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

    <!--配置对象创建-->
    <bean id="userService" class="WaiBuBean.UserService">
        <!--注入userDao对象
        name属性：类里面属性名称
        ref属性：创建userDao对象bean标签id值
        -->
        <property name="userDao" ref="userDaoImpl"></property>
    </bean>
    <bean id="userDaoImpl" class="WaiBuBean.UserDaoImpl"></bean>
</beans>

Test

public class WBeanTest {
    @Test
    public void testBean() {
        //加载 Spring 配置文件
        ApplicationContext context =
                new ClassPathXmlApplicationContext("WaiBuBean.xml");
        //获取配置创建的对象
        UserService userService = context.getBean("userService", UserService.class);

        userService.add();
    }
}