spring ioc的简单实例及bean的作用域属性解析

/**
 * 实体Bean
 * @author BC
 *
 */
public class User {
	private Integer id;
	private String userName;
	private String passWord;
	//get set方法略
}
/**
 * 数据访问层接口
 * @author BC
 *
 */
public interface UserDaoInterface {
	/**查询所有用户信息*/
	public List<User> getUserList();
}
/**
 * 数据访问层实现类
 * @author BC
 *
 */
public class UserDaoImpl implements UserDaoInterface {
	/**模拟数据库数据*/
	private List<User> userList;
	public UserDaoImpl() {
		userList = new ArrayList<User>();
		User u = new User(1, "张三", "123");
		userList.add(u);
		u = new User(2, "李四", "456");
		userList.add(u);
		u = new User(3, "王五", "789");
		userList.add(u);
		u = new User(4, "赵六", "233");
		userList.add(u);
	}
	@Override
	 public List<User> getUserList() {
		return userList;
	}
}
/**
 * 业务逻辑层接口
 * @author BC
 *
 */
public interface UserBizInterface {
	/**查询所有用户信息*/
	public List<User> getUserList();
}
/**
 * 业务逻辑层实现类
 * @author BC
 *
 */
public class UserBizImpl implements UserBizInterface {
	/**使用Spring注入*/
	private UserDaoInterface userDao;
	@Override
	 public List<User> getUserList() {
		return userDao.getUserList();
	}
	/**通过set方法注入,因此需要注入的属性必须设置set方法*/
	public void setUserDao(UserDaoInterface userDao) {
		this.userDao = userDao;
	}
	public UserDaoInterface getUserDao() {
		return userDao;
	}
}

<?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:p="http://www.springframework.org/schema/p"
 xsi:schemaLocation="http://www.springframework.org/schema/beans 
 http://www.springframework.org/schema/beans/spring-beans-4.1.xsd">

 <!-- 数据访问层对象：UserDao -->
 <bean id="userDao" class="com.bc.dao.impl.UserDaoImpl"></bean>
 <!-- 业务逻辑层对象：UserBiz --> 
 <bean id="userBiz" class="com.bc.biz.impl.UserBizImpl">
  <!-- 通过set方法注入数据访问层属性 -->
  <property name="userDao" ref="userDao"/>
 </bean>

public class UserBizTest {
	private ApplicationContext ctx;
	@Before
	 public void load() {
		//读取applicationContext.xml配置文件
		ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
	}
	@Test
	 public void getUserListTest() {
		//创建一个业务逻辑层对象
		UserBizInterface userDao = (UserBizInterface) ctx.getBean("userBiz");
		//调用方法获取用户信息
		List<User> userList = userDao.getUserList();
		//遍历集合
		for (User user : userList) {
			System.out.println(user.getId() + "|" + user.getUserName() + "|" +user.getPassWord());
		}
	}
}