Spring详细创建流程如下

1）创建Maven工程

打开idea主界面

new Project ===> Name ==> Language ===> Maven ===> JDK ===> GroupId ===> Create

Src ===> 鼠标右键===>Delete

 创建module

鼠标右键spring-demo ===> new ===> Module

new Module ===> Name ==> Language ==> Build System ===> Jdk ==>Create

 

2）导入依赖

<!--导入spring-context依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>6.1.12</version>
        </dependency>
        <!--导入测试依赖-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>

导入maven依赖

spring01下的pom.xml文件

3）创建MySrping.config

鼠标右击resourse文件 ===> new  ===> XML  ==> SpringConfig

<?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">


    
</beans>

4）创建Users类

package org.xiji;

/**
 * 自定义类
 */
public class Users {

    public void userInfo(){
        System.out.println("userInfo");
    }
}

5）编写MyConfig.xml文件的bean

<?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">


    <!-- id 定义bean的id  -->
    <!-- class (包名+类名) 即Users类所在的路径 -->
    <bean id="users" class="org.xiji.Users">

    </bean>
    
</beans>

6）手动创建Users类

import org.junit.Test;
import org.xiji.Users;

public class CreateUsersByHandTest {

    @Test
    public void createUsers(){
        System.out.println("通过手写创建");
        Users users = new Users();
        System.out.println(users);
        users.userInfo();
    }
}

测试结果

7）通过spring框架的ClassPathXmlApplicationContext 创建对象

new ClassPathXmlApplicationContext("加载指定配置类") ==> 加载bean

import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.xiji.Users;

public class CreateUsersBySpringTest {
    @Test
    public void test(){
        System.out.println("使用spring框架创建");

        //通过xml文件创建对象  == >  加载指定的配置类
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("MyConfig.xml");
        Users users = context.getBean("users", Users.class);
        System.out.println(users);
        users.userInfo();

    }
}

测试结果

8）通过反射创建对象

通过java反射机制 Class.forName("类的全类名") ===> 获取构造器 ==》 实例化对象 ==》强转 ==》o.userInfo()

import org.junit.Test;
import org.xiji.Users;

public class CreateBeanByReflectTest {
    /**
     * 反射创建
     * spring是通过反射创建类的
     */
    @Test
    public void createBeanByReflect() throws Exception {
        System.out.println("通过反射创建");
        //通过类的全路径创建类
        Class aClass = Class.forName("org.xiji.Users");

        /**
         * 获取构造器，然后创建对象
         */
        Users o = (Users) aClass.getDeclaredConstructor().newInstance();

        System.out.println(o);
        o.userInfo();

    }
}

测试结果