​​Spring6梳理17——基于XML的自动装配

以上笔记来源：
尚硅谷Spring零基础入门到进阶，一套搞定spring6全套视频教程（源码级讲解）https://www.bilibili.com/video/BV1kR4y1b7Qc

目录

①引入

②场景模拟

2.1  创建UserController类文件

 2.2  创建UserService接口文件

 2.3  创建UserServiceImpl实现类文件

2.4  创建UserDao接口文件

2.5  创建UserDaoImpl实现类文件 

2.6  创建XML配置文件

2.6.1  根据类型进行自动装配

 2.6.2  根据名称进行自动装配

2.6  创建测试类文件

2.7  运行截图

③总结

---

①引入

自动装配：根据指定的策略，在IOC容器中匹配某一个bean，自动为指定的bean中所依赖的类类型或接口类型属性赋值

②场景模拟

2.1  创建UserController类文件

package com.atguigu.spring6.iocxml.auto.controller;

import com.atguigu.spring6.iocxml.auto.dao.UserDao;
import com.atguigu.spring6.iocxml.auto.dao.UserDaoImpl;
import com.atguigu.spring6.iocxml.auto.service.UserService;
import com.atguigu.spring6.iocxml.auto.service.UserServiceImpl;

/**
 * @package: com.atguigu.spring6.iocxml.auto.controller
 * @className: UserController
 * @Description:
 * @author: haozihua
 * @date: 2024/10/19 16:34
 */
public class UserController {
    private UserService userService;

    public void setUserService(UserService userService) {
        this.userService = userService;
    }

    public void addUser(){
        System.out.println("Controller方法执行了...");
        //调用Service的方法
        userService.addUserService();
//        UserService userService = new UserServiceImpl();
//        userService.addUserService();
    }
}

 2.2  创建UserService接口文件

package com.atguigu.spring6.iocxml.auto.service;

public interface UserService {
    public void addUserService();
}

 2.3  创建UserServiceImpl实现类文件

package com.atguigu.spring6.iocxml.auto.service;

import com.atguigu.spring6.iocxml.auto.dao.UserDao;
import com.atguigu.spring6.iocxml.auto.dao.UserDaoImpl;
import com.atguigu.spring6.iocxml.factorybean.User;

/**
 * @package: com.atguigu.spring6.iocxml.auto.service
 * @className: UserServiceImpl
 * @Description:
 * @author: haozihua
 * @date: 2024/10/19 16:35
 */
public class UserServiceImpl implements UserService{
    private UserDao userDao;
    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

    @Override
    public void addUserService() {
        System.out.println("userService方法执行了...");
        //调用dao方法
        userDao.addUserDao();
//        UserDao userDao = new UserDaoImpl();
//        userDao.addUserDao();
    }
}

2.4  创建UserDao接口文件

package com.atguigu.spring6.iocxml.auto.dao;

public interface UserDao {
    public void addUserDao();
}

2.5  创建UserDaoImpl实现类文件 

package com.atguigu.spring6.iocxml.auto.dao;

/**
 * @package: com.atguigu.spring6.iocxml.auto.dao
 * @className: UserDaoImpl
 * @Description:
 * @author: haozihua
 * @date: 2024/10/19 16:38
 */
public class UserDaoImpl implements UserDao {

    @Override
    public void addUserDao() {
        System.out.println("addUserDao方法执行了...");
    }
}

2.6  创建XML配置文件

2.6.1  根据类型进行自动装配

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <!--根据类型自动装配-->
    <bean id="userController" class="com.atguigu.spring6.iocxml.auto.controller.UserController"
          autowire="byType">
    </bean>
    <bean id="userService" class="com.atguigu.spring6.iocxml.auto.service.UserServiceImpl"
          autowire="byType">
    </bean>
    <bean id="userDao" class="com.atguigu.spring6.iocxml.auto.dao.UserDaoImpl"></bean>

</beans>

 2.6.2  根据名称进行自动装配

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--根据名称自动装配-->
        <bean id="userController" class="com.atguigu.spring6.iocxml.auto.controller.UserController"
              autowire="byName">
        </bean>
        <bean id="userService" class="com.atguigu.spring6.iocxml.auto.service.UserServiceImpl"
              autowire="byName">
        </bean>
        <bean id="userDao" class="com.atguigu.spring6.iocxml.auto.dao.UserDaoImpl"></bean>

</beans>

2.6  创建测试类文件

package com.atguigu.spring6.iocxml.auto;

import com.atguigu.spring6.iocxml.auto.controller.UserController;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @package: com.atguigu.spring6.iocxml.auto
 * @className: Test
 * @Description:
 * @author: haozihua
 * @date: 2024/10/19 17:01
 */
public class TestUser {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean-auto.xml");
        UserController userController = context.getBean("userController", UserController.class);
        userController.addUser();

    }
}

2.7  运行截图

③总结

实现XML的自动装配一共有两种方式可以实现，通过类型和名称均可以进行装配，需要注意的是，当按照类型进行自动装配时，需要注意接口的实现类是否有多个，当接口的实现类有多个时，就会产生如下异常，需要注意。

org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'com.atguigu.spring6.bean.HelloWorld' available: expected single matching bean but found 2: helloworldOne,helloworldTwo