基于Java配置类的方式实现

通过在类头部使用@Configuration注解表示这个类为Spring的配置类，相当于applicationContext.xml配置文件。

package com.gupaoedu;

import com.gupaoedu.pojo.User;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;


@Configuration
public class JavaConfig {

    
    @Bean(name = {"aaa","bbb"})
    public User getUser(){
        User user = new User();
        //user.set....
        return user;
    }
    
    @Bean
    
    public IUserDao userDao(){
        return new UserDaoImpl();
    }

    
    @Bean
    public IUserService userService(IUserDao userDao){
        IUserService userService = new UserServiceImpl();
        ((UserServiceImpl) userService).setDao(userDao);
        return userService;
    }

    @Bean
    public UserController userController(IUserService userService){
        UserController controller = new UserController();
        controller.setService(userService);
        return controller;
    }
}

public class MainTest1 {

    @Test
    public void fun1(){
        // 通过@Configuraction注解来初始化IoC容器
        ApplicationContext ac = new AnnotationConfigApplicationContext(JavaConfig.class);
        System.out.println(ac.getBean("aaa",User.class));
    }
}