Spring IOC容器内部机制探究

Spring Framework有两大基石：IOC容器和AOP，本篇通过一个简单的Spring IOC示例 debug来探究一下Spring FrameworkIOC容器内部实现。

示例

import com.bytebeats.spring.research.model.User;
import com.bytebeats.spring.research.service.UserService;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.core.io.ClassPathResource;

/**
 * Hello world!
 *
 */
public class App {

    public static void main( String[] args ) {

        ClassPathResource resource = new ClassPathResource("spring-bean.xml");
        DefaultListableBeanFactory factory = new DefaultListableBeanFactory();
        XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(factory);
        reader.loadBeanDefinitions(resource);

        User user = new User();
        user.setId(15L);
        user.setName("ricky");
        //测试类
        UserService userService = factory.getBean("userService", UserService.class);
        boolean success = userService.addUser(user);
        System.out.println("success:"+success);
    }
}

spring-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"
       xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <bean id="userDao" class="com.bytebeats.spring.research.dao.UserDao" />
    
    <bean id="userService" class="com.bytebeats.spring.research.service.impl.UserServiceImpl">
        <property name="userDao" ref="userDao" />
    </bean>
    
</beans>

UserDao

public class UserDao {

    public int insert(User user){

        return 1;
    }
}

UserService

public interface UserService {

    boolean addUser(User user);
}

UserServiceImpl

public class UserServiceImpl implements UserService {

    private UserDao userDao;

    @Override
    public boolean addUser(User user) {
        int update = userDao.insert(user);
        return update>0;
    }

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }
}