Spring--bean的作用范围

在Spring中，bean的作用范围分以下几种：　

　　singleton：spring ioc容器中仅有一个bean实例，bean以单例的方式存在
　　prototype：每次从容器中调用bean时，都返回一个新的实例
　　request：每次http请求都会创建一个新的bean
　　session：同一个http session共享一个bean
　　global session：同一个全局session共享一个bean 一般用于portlet应用环境
　　application：同一个application共享一个bean

singleton

 package com.fuwh.test;

 public class Dog {

     public int id;
     public String name;
     public int age;
     public int getId() {
         return id;
     }
     public void setId(int id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public int getAge() {
         return age;
     }
     public void setAge(int age) {
         this.age = age;
     }
     @Override
     public String toString() {
         return "Dog [id=" + id + ", name=" + name + ", age=" + age + "]";
     }

 }

 <?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="dog" class="com.fuwh.test.Dog" scope="singleton">
         <property name="id" value="001"></property>
         <property name="name" value="heihu"></property>
         <property name="age" value="5"></property>
     </bean>   

 </beans>

 package com.fuwh.test;

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

 public class Test {

     private ApplicationContext ac;    

     @Before
     public void setUp() throws Exception {
         ac=new ClassPathXmlApplicationContext("beans.xml");
     }

     @org.junit.Test
     public void test() {
         System.out.println(ac.getBean("dog")==ac.getBean("dog"));
     }
 }

返回结果 ： true

 <?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="dog" class="com.fuwh.test.Dog" scope="prototype">
         <property name="id" value="001"></property>
         <property name="name" value="heihu"></property>
         <property name="age" value="5"></property>
     </bean>   

 </beans>

 package com.fuwh.test;

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

 public class Test {

     private ApplicationContext ac;    

     @Before
     public void setUp() throws Exception {
         ac=new ClassPathXmlApplicationContext("beans.xml");
     }

     @org.junit.Test
     public void test() {
         System.out.println(ac.getBean("dog")==ac.getBean("dog"));
     }
 }

返回结果：false