spring中Autowired和Qulifier注解

在使用注解的时候，首先得在配置文件bean.xml中添加命名空间：

xmlns:context="http://www.springframework.org/schema/context"

 

然后在xsi:schemaLocation中添加：

http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd

 

再次引入：

<context:annotation-config/>

 

bean.xml

<?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-2.5.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd">
	
	<context:annotation-config/>
	
	<bean id="userDAOImpl" class="com.test.dao.impl.UserDAOImpl"></bean>
	<bean id="userDAOImpl2" class="com.test.dao.impl.UserDAOImpl"></bean>
	
	<bean id="userService" class="com.test.service.UserService"></bean>

</beans>

 

UserService.java

package com.test.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;

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

public class UserService {
	private UserDAO userDAO;

	public void add(User user) {
		userDAO.save(user);
	}
	
	public UserDAO getUserDAO() {
		return userDAO;
	}
	// Autowired默认按类型by type，如果想用byName，使用Qulifier
	// 如果beans.xml中有多个UserDAOImpl配置，在这里用Qualifier进行标明
	@Autowired
	public void setUserDAO(@Qualifier("userDAOImpl")UserDAO userDAO) {
		this.userDAO = userDAO;
	}
	
}