抽象类中注入bean，并且该bean为private的，spring是如何实现注入的 ？

[qq_26169787]

在spring工程中定义了抽象类，抽象类中使用注解注入bean，并且该bean为private的，该抽象类的子类使用注解加入到了IOC容器中，private的变量子类无法继承，如果是public的，子类可以继承过去，应该可以通过子类实现注入，但是该bean是声明为private的，spring是如何实现注入的 ？
使用@Resource和@AutoWired的结果是一样的。


包结构如图



spring.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.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd">

	<context:component-scan base-package="dao,service"></context:component-scan>

	<bean class="session.Session"></bean>

</beans>

Session定义：

package session;

public class Session {

	public void save(){
		System.out.println("save entity....");
	}
	
	public void update(){
		System.out.println("update entity...");
	}
	
}

User:

package session;

public class User {

}

BaseDao定义：

package dao;

public interface BaseDao<T> {

	public void save();
	
	public void update();
}

BaseDaoImpl定义：

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

import dao.BaseDao;
import session.Session;

public abstract class BaseDaoImpl<T> implements BaseDao<T>{

	@Autowired
	private Session session;

	@Override
	public void save() {
		session.save();
	}

	@Override
	public void update() {
		session.update();
	}
	
}

UserDao定义：

package dao.impl;

import org.springframework.stereotype.Repository;

import session.User;

@Repository("userDao")
public class UserDaoImpl extends BaseDaoImpl<User>{
	
}

BaseService定义：

package service;

public interface BaseService<T> {

	public void save();

	public void update();

}

UserService定义：

package service;

import session.User;

public interface UserService extends BaseService<User> {
	
}

BaseServiceImpl定义：

package service.impl;

import javax.annotation.Resource;

import dao.BaseDao;
import service.BaseService;

public abstract class BaseServiceImpl<T> implements BaseService<T>{

	private BaseDao<T> baseDao;
	
	@Resource
	public void setBaseDao(BaseDao<T> baseDao) {
		this.baseDao = baseDao;
	}
	
	@Override
	public void save() {
		// TODO Auto-generated method stub
		baseDao.save();
	}

	@Override
	public void update() {
		// TODO Auto-generated method stub
		baseDao.update();
	}

}

UserServiceImpl定义：

package service.impl;

import javax.annotation.Resource;

import org.springframework.stereotype.Service;

import dao.BaseDao;
import service.UserService;
import session.User;

@Service("userService")
public class UserServiceImpl extends BaseServiceImpl<User> implements UserService {

	@Resource(name="userDao")
	public void setBaseDao(BaseDao<User> baseDao) {
		// TODO Auto-generated method stub
		super.setBaseDao(baseDao);
	}
}

TestCase：

package test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import service.UserService;

public class TestCase {

	@Test
	public void test() {
		ApplicationContext ac = new ClassPathXmlApplicationContext("spring.xml");
		UserService us = (UserService) ac.getBean("userService");
		us.save();
	}

}

运行结果

[missMeyo]

去看Spring源码解析。