Spring框架之控制反转和依赖注入

学Spring框架必须理解控制反转和依赖注入。下面各自举一个例子，来说明。

IOC(控制反转):应用本身创建和维护的依赖对象；现在交由外部容器(Spring)来创建和维护；这个控制权的转移；
就叫做控制反转。

第一步：配置applicationContextcreateproject.xml和applicationcontext.xml（总体）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

     <bean id="create" class="createObject.CreateHelloWorld"  factory-method="create">

     </bean>
</beans>

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<!-- 引用其他配置文件 -->

    <import resource="createObject/applicationContextcreateproject.xml"/>
</beans>

package createObject;

public class CreateHelloWorld {
    //静态工厂
    public static HelloWord create(){

        return new HelloWord();
    }

}

package createObject;

public class HelloWord {
    public void hellow(){
        System.out.print("hellow spring");
    }

}

测试类：

package createObject;

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

public class texthell{
    public static void main(String[] args) {

    // TODO Auto-generated method stub
   //加载配置文件
       ApplicationContext context=new ClassPathXmlApplicationContext("applicationcontext.xml");
       HelloWord te=(HelloWord) context.getBean("create");
       te.hellow();

}
}

效果图：

DI(依赖注入):（控制反转的一个实现）在程序运行期间；动态的将依赖对象注入到组件当中（创建对象）new的工作交给spring来做；前提留接口;set get方法

第一步：配置Springapplicationcontext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<bean id="wanlix" class="com.Test.test">
<property name="name" value="张嘎"/>
<property name="speak" value="一天不打黄鼠狼，就憋屈"/>

</bean>

</beans>

第二步：测试类

package com.Test;

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

public class test {
    public String name;
    public String speak;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSpeak() {
        return speak;
    }
    public void setSpeak(String speak) {
        this.speak = speak;
    }
    public static void main(String[] args) {

        ApplicationContext context=new ClassPathXmlApplicationContext("applicationcontext.xml");

        test te=(test) context.getBean("wanlix");
        System.out.print(te.getName()+"说:"+te.getSpeak());
    }

}

效果图：