Spring IoC实现解耦合

public class UserDaoImpl implements UserDao{
    @Override
    public void save(User user) {
        // TODO Auto-generated method stub
        System.out.println("保存用户信息到数据库");

public class UserServiceImpl implements UserService{
    private UserDao userDao;

    public UserDao getUserDao() {
        return userDao;
    }
    //后面要调用该方法
    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }
    @Override
    public void addUser(User user) {
        // TODO Auto-generated method stub
        userDao.save(user);
    }
}

测试类  获取Bean的实例，调用功能方法

@Test
    public void test() {
        ApplicationContext context = new ClassPathXmlApplicationContext
                         ("applicationContext.xml");
        UserServiceImpl service =  (UserServiceImpl)context.getBean("userServiceImpl");//此处是xml中id
        User user = (User) context.getBean("user");
        user.setUsername("admin");
        user.setPassword("123");
        
        service.addUser(user);
    }

xml文件   配置文件，给Service对应的Bean注入Dao对象

<?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-3.1.xsd ">
    
    <!-- 定义userDaoImpl对象,并指定id为userDaoImpl -->
    <bean id="userDaoImpl" class="cn.bdqn.biz.dao.impl.UserDaoImpl" />
    <!-- 定义User对象,并指定id为user -->
    <bean id="user" class="cn.bdqn.biz.pojo.User" />
    
    <!-- 定义UserServiceImpl对象,并指定id为userServiceImpl -->
    <bean id="userServiceImpl" class="cn.bdqn.biz.service.impl.UserServiceImpl">
        <!--为userServiceImpl的userDao属性赋值,需要注意的是,这里要调用setUserDao()方法 -->
        <property name="userDao">
            <!-- 引用id为userDao的对象为userServiceImpl的userDao属性赋值 -->
            <ref bean="userDaoImpl" />
        </property>
    </bean>
    
</beans>