第六讲 --Spring管理的Bean的生命周期

 

      容器什么时候实力化我们的业务bean呢? 我们可以写一个简单的测试方法,给业务bean增加一个不带参数的构造方法,看看容器是什么时候实例化我们的业务bean的.

 

PersionServiceBean.java

  

package cn.com.xinli.service.impl; import org.apache.log4j.Logger; import cn.com.xinli.service.PersionSevice; public class PersionServiceBean implements PersionSevice { Logger log=Logger.getLogger(PersionServiceBean.class); public PersionServiceBean() { log.info("我被实例化了"); } public void save() { log.info("我是save()方法!"); } }

 

 运行:

ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml"); //PersionSevice ps=(PersionSevice)ctx.getBean("persionServiceBean"); //log.info(ps); //ps.save();

 日志:

2009-05-24 17:41:04,968  INFO (PersionServiceBean.java:13) - 我被实例化了

 

可见在启动容器的时候spring就完成业务bean的实例化了,如果我们不想在容器启动的时候实例化我们的业务bean,我们可以指定 lazy-init="true"

对于 scope 为:prototype (原型)的 bean, 在spring 容器启动的时候并不被实例化,不管你是不是指定lazy-init="false" ,它只有在使用的时候才初始化

 

 

指定Bean的初始化方法和销毁方法 

 

 

package cn.com.xinli.service.impl; import org.apache.log4j.Logger; import cn.com.xinli.service.PersionSevice; public class PersionServiceBean implements PersionSevice { Logger log=Logger.getLogger(PersionServiceBean.class); public void init() { log.info("初始化资源"); } public PersionServiceBean() { log.info("我被实例化了"); } public void save() { log.info("我是save()方法!"); } public void destory() { log.info("释放资源"); } }

 

 

在 <bean id="persionServiceBean" class="cn.com.xinli.service.impl.PersionServiceBean" init-method="init" destroy-method="destory"></bean>

 

测试:

ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml"); PersionSevice ps=(PersionSevice)ctx.getBean("persionServiceBean"); ctx.close();

 

 

打印:

 2009-05-24 19:24:14,578  INFO (PersionServiceBean.java:17) - 我被实例化了2009-05-24 19:24:14,687  INFO (PersionServiceBean.java:13) - 初始化资源2009-05-24 19:24:14,687  INFO (AbstractApplicationContext.java:815) - Closing org.springframework.context.support.ClassPathXmlApplicationContext@7b7072: display name [org.springframework.context.support.ClassPathXmlApplicationContext@7b7072]; startup date [Sun May 24 19:24:13 CST 2009]; root of context hierarchy2009-05-24 19:24:14,687  INFO (DefaultSingletonBeanRegistry.java:421) - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@bfc8e0: defining beans [persionServiceBean]; root of factory hierarchy2009-05-24 19:24:14,703  INFO (PersionServiceBean.java:26) - 释放资源