Spring入门案例创建流程

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 {@Testpublic 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 {@Testpublic 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*/@Testpublic 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