Spring实战之Bean的作用域singleton和prototype用法分析

<?xml version="1.0" encoding="GBK"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns="http://www.springframework.org/schema/beans"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
  http://www.springframework.org/schema/beans/spring-beans-4.0.xsd">
  <!-- 配置一个singleton Bean实例 -->
  <bean id="p1" class="org.crazyit.app.service.Person"/>
  <!-- 配置一个prototype Bean实例 -->
  <bean id="p2" class="org.crazyit.app.service.Person"
   scope="prototype"/>
  <bean id="date" class="java.util.Date"/>
</beans>

package org.crazyit.app.service;
public class Person
{
  private int age;
}

package lee;
import org.springframework.context.*;
import org.springframework.context.support.*;
public class BeanTest
{
 public static void main(String[] args)throws Exception
 {
  // 以类加载路径下的beans.xml文件创建Spring容器
  ApplicationContext ctx = new
   ClassPathXmlApplicationContext("beans.xml"); // ①
  // 判断两次请求singleton作用域的Bean实例是否相等
  System.out.println(ctx.getBean("p1")
   == ctx.getBean("p1"));
  // 判断两次请求prototype作用域的Bean实例是否相等
  System.out.println(ctx.getBean("p2")
   == ctx.getBean("p2"));
  System.out.println(ctx.getBean("date"));
  Thread.sleep(1000);
  System.out.println(ctx.getBean("date"));
 }
}