Spring 5.x 源码之旅-32getBean详解十七销毁回调

    protected void registerDisposableBeanIfNecessary(String beanName, Object bean, RootBeanDefinition mbd) {
    		AccessControlContext acc = (System.getSecurityManager() != null ? getAccessControlContext() : null);
    		if (!mbd.isPrototype() && requiresDestruction(bean, mbd)) {//有销毁接口的
    			if (mbd.isSingleton()) {//单例的情况，注册销毁回调
    				// Register a DisposableBean implementation that performs all destruction
    				// work for the given bean: DestructionAwareBeanPostProcessors,
    				// DisposableBean interface, custom destroy method.
    				registerDisposableBean(beanName,
    						new DisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc));
    			}
    			else {//自定义的，注册到Scope
    				// A bean with a custom scope...
    				Scope scope = this.scopes.get(mbd.getScope());
    				if (scope == null) {
    					throw new IllegalStateException("No Scope registered for scope name '" + mbd.getScope() + "'");
    				}
    				scope.registerDestructionCallback(beanName,
    						new DisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc));
    			}
    		}
    	}

requiresDestruction

检查是否是有销毁的方法注册的，有方法名都是可以的，或者有DestructionAwareBeanPostProcessor处理器来判断的。

    	protected boolean requiresDestruction(Object bean, RootBeanDefinition mbd) {
    		return (bean.getClass() != NullBean.class &&
    				(DisposableBeanAdapter.hasDestroyMethod(bean, mbd) || (hasDestructionAwareBeanPostProcessors() &&
    						DisposableBeanAdapter.hasApplicableProcessors(bean, getBeanPostProcessors()))));
    	}

DisposableBeanAdapter的hasDestroyMethod销毁方法名

实现DisposableBean和AutoCloseable 接口的，或者INFER_METHOD等于destroyMethodName 且有close，shutdown方法名的

    	public static boolean hasDestroyMethod(Object bean, RootBeanDefinition beanDefinition) {
    		if (bean instanceof DisposableBean || bean instanceof AutoCloseable) {
    			return true;
    		}
    		String destroyMethodName = beanDefinition.getDestroyMethodName();
    		if (AbstractBeanDefinition.INFER_METHOD.equals(destroyMethodName)) {
    			return (ClassUtils.hasMethod(bean.getClass(), CLOSE_METHOD_NAME) ||
    					ClassUtils.hasMethod(bean.getClass(), SHUTDOWN_METHOD_NAME));
    		}
    		return StringUtils.hasLength(destroyMethodName);
    	}

DisposableBeanAdapter的hasApplicableProcessors

如果有处理器来处理的话。

    public static boolean hasApplicableProcessors(Object bean, List<BeanPostProcessor> postProcessors) {
    		if (!CollectionUtils.isEmpty(postProcessors)) {
    			for (BeanPostProcessor processor : postProcessors) {
    				if (processor instanceof DestructionAwareBeanPostProcessor) {
    					DestructionAwareBeanPostProcessor dabpp = (DestructionAwareBeanPostProcessor) processor;
    					if (dabpp.requiresDestruction(bean)) {
    						return true;
    					}
    				}
    			}
    		}
    		return false;
    	}

DefaultSingletonBeanRegistry的registerDisposableBean

其实就是把bean注册进去，到时候回调就行。

    	public void registerDisposableBean(String beanName, DisposableBean bean) {
    		synchronized (this.disposableBeans) {
    			this.disposableBeans.put(beanName, bean);
    		}
    	}

最后容器销毁的时候会调用：