spring @Autowired @Qualifier

package com.bjsxt.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;

import com.bjsxt.dao.UserDAO;
import com.bjsxt.model.User;

public class UserService {
private UserDAO userDAO;
public void add(User user) {
userDAO.save(user);
}
public UserDAO getUserDAO() {
return userDAO;
}
@Autowired
public void setUserDAO(@Qualifier("userDAO") UserDAO userDAO) {
this.userDAO = 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:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> 
<context:annotation-config></context:annotation-config>

<bean name="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl">
</bean>
<bean name="u" class="com.bjsxt.dao.impl.UserDAOImpl">
</bean>

<bean id="userService" class="com.bjsxt.service.UserService" >

<!--<property name="userDAO" ref="userDAO"> </property>   -->
</bean>

</beans>

package com.bjsxt.service;

import org.junit.Test;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.bjsxt.model.User;

public class UserServiceTest {

@Test
public void testAdd() throws Exception {
BeanFactory applicationContext = new ClassPathXmlApplicationContext("beans.xml");

UserService service = (UserService)applicationContext.getBean("userService");

service.add(new User());
}
}