SpringIOC_对象的多实例和单实例

<?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-2.5.xsd">
           
    <bean id="helloWorld" class="com.spring.scope.HelloWord"></bean>
    
    <bean id="helloWorld2" class="com.spring.scope.HelloWord" 
    scope="prototype"></bean>
    
        
</beans>

package com.spring.scope;

public class HelloWord {
    
    public HelloWord(){
        
        System.out.println("create Object");
    }
    
    public void hello(){
        System.out.println("hello word!");
    }

}

package com.spring.scope.test;

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

import com.spring.scope.HelloWord;

public class HelloWordTest {
    
    /**
     * 
     *在Spring容器中的对象，默认情况下是单例的
     *    因为对象是单列的,所以只要在类上声明一个属性，该属性含有数据，那么这个该属性将是全局的 (危险)
     */
    @Test
    public void testScope_Default(){
        
        //启动Spring容器
        ApplicationContext context=
                new ClassPathXmlApplicationContext("applicationContext.xml");
        
        //根据id把Spring容器中的bean提取出来
        HelloWord helloWord = (HelloWord) context.getBean("helloWorld");
        HelloWord helloWord2 = (HelloWord) context.getBean("helloWorld");
        
         System.out.println(helloWord);
         System.out.println(helloWord2);
         //create Object
        //com.spring.scope.HelloWord@29a3a9db
        //com.spring.scope.HelloWord@29a3a9db
        
    }
    
    
    /**
     * 
     * 如果scope为prototype，Spring容器产生的对象就是多例
     *
     * 如果一个对象为多例，这个对象在Spring容器中创建时机就会发生改变，则不会再启动的时候创建对象,会再getBean()才创建对象
     *  即:
     *   如果scope为prototype，则无论Lazy-init为什么值，都是在 context.getBean()时创建对象。
     * 
     */
    @Test
    public void testScope_Prototype(){
        //启动Spring容器
        ApplicationContext context=
                new ClassPathXmlApplicationContext("applicationContext.xml");
        
        //根据id把Spring容器中的bean提取出来
        HelloWord helloWord = (HelloWord) context.getBean("helloWorld2");
        HelloWord helloWord2 = (HelloWord) context.getBean("helloWorld2");
        
         System.out.println(helloWord);
         System.out.println(helloWord2);
         
      /* create Object
         create Object
         com.spring.scope.HelloWord@79d0e2d2
         com.spring.scope.HelloWord@db8779    */
        
    }
    
    

}