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>