Spring入门

Spring

什么是Spring

Spring的优点

Spring模块

Spring的IoC

Spring的IoC底层原理

Example

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>4.2.4.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>4.2.4.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>4.2.4.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-expression</artifactId>
      <version>4.2.4.RELEASE</version>
    </dependency>

package com.jesse.ioc.demo1;

public interface UserService {
    public void sayHello();
}

package com.jesse.ioc.demo1;

public class UserServiceImpl implements UserService {
    @Override
    public void sayHello() {
        System.out.println("Hello Spring");
    }
}

<?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">
    <!-- UserService的创建权交给了Spring -->
    <bean id="userService" class="com.jesse.ioc.demo1.UserServiceImpl"></bean>

</beans>

package com.jesse.ioc.demo1;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SpringDemo1 {

    @Test
    /**
     * 传统方式开发
     */
    public void demo1(){
        UserService userService = new UserServiceImpl();
        userService.sayHello();
    }

    @Test
    /**
     * Spring的方式实现
     */
    public void demo2(){
        //创建Spring的工厂
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        //通过工厂获得类
        UserService userService =  (UserService)applicationContext.getBean("userService");
        userService.sayHello();
    }
}

IoC和DI

Spring入门

原文：https://www.cnblogs.com/jessekkk/p/12790628.html