Spring之开发步骤的代码实现

• 导入spring开发的基本包坐标

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>5.0.5.RELEASE</version>
</dependency>

• 编写Dao接口和实现类

package com.itheima.dao;

public interface UserDao {
    public void save();
}

package com.itheima.dao.impl;

import com.itheima.dao.UserDao;

public class UserDaoImpl implements UserDao {
    public void save() {
        System.out.println("save running....");
    }
}

• 创建spring核心配置文件
• 在spring配置文件中配置UserDaoImpl

<?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">
    <bean id="userDao" class="com.itheima.dao.impl.UserDaoImpl" />
</beans>

• 使用spring的API获得Bean实例

package com.itheima.demo;

import com.itheima.dao.UserDao;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserDaoDemo {
    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserDao userDao = (UserDao) applicationContext.getBean("userDao");
        userDao.save();
    }
}