【Spring注解系列09】Spring初始化和销毁接口-InitializingBean与DisposableBean

末蓝、 2022-02-24 06:40 299阅读 0赞

# 1.InitializingBean与DisposableBean #

**InitializingBean**

定义初始化逻辑，用于执行自定义初始化或者校验已设置的属性值等。

* Interface to be implemented by beans that need to react once all their properties
    * have been set by a {@link BeanFactory}: e.g. to perform custom initialization,
    * or merely to check that all mandatory properties have been set.

**DisposableBean**

定义销毁逻辑，用于一个实例bean销毁后需要释放资源等。 只有bean从容器中移除或者销毁或容器关闭时，才会调用该方法。

ApplicationContext关闭时，默认对所有单例bean都会调用这个方法。

* Interface to be implemented by beans that want to release resources on destruction.
    * A {@link BeanFactory} will invoke the destroy method on individual destruction of a
    * scoped bean. An {@link org.springframework.context.ApplicationContext} is supposed
    * to dispose all of its singletons on shutdown, driven by the application lifecycle.

## 2.实例 ##

//实现InitializingBean,DisposableBean接口的bean
    public class BeanLife implements InitializingBean,DisposableBean{
    
        public BeanLife() {
            System.out.println("BeanLife--->construct...");
        }
    
    
        @Override
        public void afterPropertiesSet() throws Exception {
            System.out.println("BeanLife--->InitializingBean.afterPropertiesSet");
        }
    
        @Override
        public void destroy() throws Exception {
            System.out.println("BeanLife--->DisposableBean.destroy");
        }
    }
    
    
    //配置类
    @Configuration
    public class BeanLifeCycleConfig {
    
       
        @Bean(value = "beanLife")
        public BeanLife life() {
            return new BeanLife();
        }
    }
    
    
    //测试
    public class BeanLifeCycleTest {
    
        public static void main(String[] args) {
            AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(BeanLifeCycleConfig.class);
            System.out.println("applicationContext ..... 初始化结束");
    
            System.out.println("applicationContext ..... 准备关闭");
            applicationContext.close();
            System.out.println("applicationContext ..... 已关闭");
    
        }
    }
    
    
    测试结果：
    BeanLife--->construct...
    BeanLife--->InitializingBean.afterPropertiesSet
    applicationContext ..... 初始化结束
    
    applicationContext ..... 准备关闭
    BeanLife--->DisposableBean.destroy
    applicationContext ..... 已关闭