一、Spring是什么?
Spring是一个框架，Java不死的原因是因为Java有Spring这个非常强大的技术框架的支持，而且他是一个轻量级的Java开发框架
二、什么是IOC？
一、IOC的意思：控制反转（全称Inversion of Control）
他是一个重要的面向对象编程的法则来消减计算机程序的耦合问题，也是轻量级的Spring框架的核心
那么如何理解这句话呢？
第一种理解：将组建对象的控制权从代码本身转移到外部容器
第二种理解：将创建对象实力的控制权从代码控制剥离到IOC容器控制
二、案例
引入jar包（引节点）
<!--Spring-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>4.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.2.0.RELEASE</version>
</dependency>
<!--aop使用的jar-->
<dependency>
<groupId> org.aspectj</groupId >
<artifactId> aspectjweaver</artifactId >
<version> 1.8.7</version >
</dependency>
里面一共有五个jar包（前两个节点有两个jar包）
创建一个类。
package demo01;
import java.util.StringTokenizer;
**
* Create Time: 2018年03月05日 16:28
* C@author 张晓北
* My motto :Do not , for one repulse , give up the purpose that you resolved to effect
**/
public class HappyService {
private String info;
private Integer age;
public HappyService(){
System.out.println("======HappyService");
}
public void work(){
System.out.println("我是"+info);
}
public String getInfo() {
return info;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public void setInfo(String info) {
this.info = info;
}
}
写ApplicationContext.xml文件
<?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="service" class="demo01.HappyService">
<property name="info" value="第一个Spring项目"></property>
<property name="age" value="10"></property>
</bean>
</beans>
测试类：
import demo01.HappyService;
import demo03.printer.Printer;
import demo03.printer.Printer;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* Create Time: 2018年03月05日 16:35
* C@author 张晓北
* My motto :Do not , for one repulse , give up the purpose that you resolved to effect
**/
public class Test20180303 {
@Test
public void t1(){
ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
HappyService service =(HappyService) context.getBean("service");
service.work();
}
}
测试结果：
====HaapyService 我是第一个Sring项目
三、什么是DI
Dependency Injection 依赖 注入 给对象注入属性值
IOC和DI的区别：
IOC控制反转：说的是创建对象实例的控制权从代码控制剥离到IOC容器控制，实际就是你在xml文件控制，侧重于原理。
DI依赖注入：说的是创建对象实例时，为这个对象注入属性值或其它对象实例，侧重于实现。它们是spring核心思想的不同方面的描述。
案例 打印机
1.编写墨盒接口
package cn.spring.day03printer.ink;
//磨盒的接口
public interface Ink {
public String getColor();
}
2.两个种墨盒
package cn.spring.day03printer.ink;
/**
* Create Time: 2018年03月05日 20:03
* C@author 张晓北
* My motto :Do not , for one repulse , give up the purpose that you resolved to effect
**/
public class BlackInk implements Ink {
//黑白墨盒
public String getColor() {
return "BlackIkn";
}
}
package cn.spring.day03printer.ink;
/**
* Create Time: 2018年03月05日 20:07
* C@author 张晓北
* My motto :Do not , for one repulse , give up the purpose that you resolved to effect
**/
//彩色墨盒
public class ColorInk implements Ink {
public String getColor() {
return "ColorIkn";
}
}
3.纸张接口和他的实现类
package cn.spring.day03printer.paper;
//纸张
public interface Paper {
public String getPaprSize();
}
package cn.spring.day03printer.paper;
/**
* Create Time: 2018年03月05日 20:13
* C@author 张晓北
* My motto :Do not , for one repulse , give up the purpose that you resolved to effect
**/
//A4纸
public class A4aper implements Paper {
public String getPaprSize() {
return "A4paper";
}
}
package cn.spring.day03printer.paper;
/**
* Create Time: 2018年03月05日 20:15
* C@author 张晓北
* My motto :Do not , for one repulse , give up the purpose that you resolved to effect
**/
//B5的纸
public class B5Paper implements Paper {
public String getPaprSize() {
return "B5Paper";
}
}
4.编写打印机类
package cn.spring.day03printer.printer;
import cn.spring.day03printer.ink.Ink;
import cn.spring.day03printer.paper.Paper;
/**
* Create Time: 2018年03月05日 20:18
* C@author 张晓北
* My motto :Do not , for one repulse , give up the purpose that you resolved to effect
**/
//打印机
public class Printer {
private Ink ink;
private Paper paper;
public void print(){
System.out.println("使用"+paper.getPaprSize()+"\t"+ink.getColor()+"墨盒,打印");
}
public Ink getInk() {
return ink;
}
public void setInk(Ink ink) {
this.ink = ink;
}
public Paper getPaper() {
return paper;
}
public void setPaper(Paper paper) {
this.paper = paper;
}
}
5.Xml文件配置
<?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">
<!--在Spring中定制一个Ink-->
<bean id="ink" class="cn.spring.day03printer.ink.ColorInk">
</bean>
<bean id="paper" class="cn.spring.day03printer.paper.A4aper">
</bean>
<bean id="printer" class="cn.spring.day03printer.printer.Printer">
<property name="paper" ref="paper"></property>
<property name="ink" ref="ink"></property>
</bean>
</beans>
6.测试类
import cn.spring.day03printer.printer.Printer;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* Create Time: 2018年03月05日 20:29
* C@author 张晓北
* My motto :Do not , for one repulse , give up the purpose that you resolved to effect
**/
public class Text03 {
@Test
public void t1(){
ApplicationContext contest=new ClassPathXmlApplicationContext("applicationContext-day03printer.xml");
Printer printer=(Printer)contest.getBean("printer");
printer.print();
}
}
运行结果:
三月 07, 2018 20:32:25 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@7c883540: startup date [Wed Mar 07 19:51:25 CST 2018]; root of context hierarchy
三月 07, 2018 20:32:25 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext-day03printer.xml]
使用A4paper ColorIkn墨盒,打印
Process finished with exit code 0
