Spring 1 IoC 2 Bean管理

部分内容摘自：http://jinnianshilongnian.iteye.com/blog/1752171

Spring IoC容器目的就是管理Bean，这些Bean将根据配置文件中的Bean定义进行创建，<bean>标签主要用来进行Bean定义

Bean定义在容器内部由BeanDefinition对象表示.

---

Bean的命名

可以用id或name指定。

<bean id=” bean” class=” cn.javass.spring.chapter2.helloworld.HelloImpl”/> 

<bean name=” bean” class=” cn.javass.spring.chapter2.helloworld.HelloImpl”/> 

public void test3() {   

          BeanFactory beanFactory =  new ClassPathXmlApplicationContext("chapter2/namingbean3.xml");   

    //根据name获取bean   

      HelloApi bean = beanFactory.getBean("bean", HelloApi.class);   

      bean.sayHello();   

}

---

实例化Bean

使用构造器实例化Bean

<bean name="bean1" class="cn.javass.spring.chapter2.HelloImpl2"/>

<bean name="bean2" class="cn.javass.spring.chapter2.HelloImpl2">   

<!-- 指定构造器参数 -->   

     <constructor-arg index="0" value="Hello Spring!"/>   

</bean> 

<bean id="messageProvider" class = "com.apress.prospring3.ch4.ConfigurableMessageProvider"

     c:_0 = "This is c:message" />

使用静态工厂方式实例化Bean

<bean id="bean3" class="cn.javass.spring.chapter2.HelloApiStaticFactory" factory-method="newInstance">   

     <constructor-arg index="0" value="Hello Spring!"/>   

</bean> 

---

使用实例工厂方法实例化Bean

<!-- the factory bean, which contains a method called createInstance() -->

<bean id="serviceLocator" class="examples.DefaultServiceLocator">

<!-- inject any dependencies required by this locator bean -->

</bean>

<!-- the bean to be created via the factory bean -->

<bean id="clientService"   factory-bean="serviceLocator"   factory-method="createClientServiceInstance"/>

public class DefaultServiceLocator {

private static ClientService clientService = new ClientServiceImpl();

private DefaultServiceLocator() {}

public ClientService createClientServiceInstance() {

      return clientService;

}

}