spring InitializingBean接口

一、接口

public interface InitializingBean { /** * Invoked by a BeanFactory after it has set all bean properties supplied * (and satisfied BeanFactoryAware and ApplicationContextAware). * <p>This method allows the bean instance to perform initialization only * possible when all bean properties have been set and to throw an * exception in the event of misconfiguration. * @throws Exception in the event of misconfiguration (such * as failure to set an essential property) or if initialization fails. */ void afterPropertiesSet() throws Exception; }

 

二、作用

利用spring的InitializingBean的afterPropertiesSet来初始化，直接看下面的demo

①、接口定义

public interface InitializingService { public void say(); }

②、接口实现类

@Component("initializingService") public class InitializingServiceImpl implements InitializingService, InitializingBean { @Override public void afterPropertiesSet() throws Exception { System.out.println("call InitializingBean"); } @Override public void say() { System.out.println("call say"); } }

③、获取bean上下文工具类实现

public class SpringContextUtil implements ApplicationContextAware { private static ApplicationContext applicationContext; // Spring应用上下文环境 @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { SpringContextUtil.applicationContext = applicationContext; } /** * 获取对象 * * @param name * @return Object 一个以所给名字注册的bean的实例 * @throws BeansException */ public static Object getBean(String name) throws BeansException { return applicationContext.getBean(name); } }

xml配置 ： spring xml 文件注入

<bean id="springContextUtil" class="com.mycompany.yuanmeng.springdemo.aop.SpringContextUtil" />

④、测试

public class InitializingBeanDemo { public static void main(String[] args) { new ClassPathXmlApplicationContext("spring.xml"); // 加载ApplicationContext（模拟启动web服务） InitializingService service = (InitializingService) SpringContextUtil.getBean("initializingService"); service.say(); } }

⑤、结果

call InitializingBean call say

这说明在spring初始化bean的时候，如果bean实现了InitializingBean接口，会自动调用afterPropertiesSet方法。