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 InitializingBeancall 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。