spring：bean的定义

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD//BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
  <!--定义一个bean,id是这个bean的唯一标识，class指出这个bean的来源，singleton指定这个bean是否是单例模式，
  depends-on指定这个bean初始化前，强制初始化date-->
  <bean id="HelloWorld" class="com.gc.action.HelloWorld" singleton="true" depends-on="date">
    <!--配置bean的属性-->
    <property name="msg">
    <value>HelloWorld!</value>
    </property>
    <!--指定bean的一个依赖-->
    <property name="date">
    <ref bean="date"/>
    </property>
  </bean>
  
  <bean id="date" class="java.util.Date"/>
</beans>

HelloWorld helloWorld = new HelloWorld();
BeanWrapper bw = new BeanWrapperlmpl(helloWorld);
bw.setPropertyValue("msg", "HelloWorld");
System.out.println(bw.getPropertyValue("msg"));

InputStream is = new FileInputStream("config.xml");
XmlBeanFactory factory = new XmlBeanFactory(is);
HelloWorld helloWorld = (HelloWorld)factory.getBean("HelloWorld");
System.out.println(helloWorld.getMsg());

ApplicationContext actx = new FileSystemXmlApplicationContext("config.xml");
HelloWorld helloWorld = (HelloWorld)actx.getBean("HelloWorld");
System.out.println(helloWorld.getMsg());