spring bean 销毁的 N 种方式 (•̀ᴗ• )

嘻嘻 /ᐠ｡ꞈ｡ᐟ

博主在 哔哩哔哩 有陆续录制了一些教学视频，有兴趣的小伙伴可以去瞅瞅，求三连~

UP主 肖-信

正文

常用方式

@PreDestroy

@PreDestroy
	private void preDestory() {
          
   
		System.out.println("销毁啦！！德玛西亚");
	}

实现 DisposableBean接口

实现 DisposableBean接口 重写 destroy方法

@Service
public class XianJian implements DisposableBean {
          
   
	@PreDestroy
	private void preDestory() {
          
   
		System.out.println("销毁啦！！德玛西亚 preDestory");
	}

	@Override
	public void destroy() throws Exception {
          
   
		System.out.println("销毁啦！！德玛西亚 destroy");
	}
}

另辟蹊径

destroyMethod

定义 Bean 指定 destoryMethod

@Bean(destroyMethod = "beanDestroyMethod")
	public XianJian xianJian() {
          
   
		return new XianJian();
	}

public class XianJian implements DisposableBean {
          
   

	@PreDestroy
	private void preDestory() {
          
   
		System.out.println("销毁啦！！德玛西亚 preDestory");
	}

	@Override
	public void destroy() throws Exception {
          
   
		System.out.println("销毁啦！！德玛西亚 destroy");
	}

	public void beanDestroyMethod(){
          
   
		System.out.println("销毁啦！！德玛西亚 beanDestroyMethod");
	}
}

AutoCloseable

实现 AutoCloseable 接口 重写 close接口

@Component
public class XianJian implements AutoCloseable{
          
   

	public void close() {
          
   
		System.out.println("销毁啦！！德玛西亚 close ");
	}

}

修改BeanDifinition

这种方式用的最少… 将 beanDefinition 的 destroyMethodName 设置为 (inferred)

@Component
public class XxxProcessor implements MergedBeanDefinitionPostProcessor {
          
   
	
	@Override
	public void postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition, Class<?> beanType, String beanName) {
          
   
		if(beanName.equals("xianJian")){
          
   
			beanDefinition.setDestroyMethodName("(inferred)");
		}
	}

	@Override
	public void resetBeanDefinition(String beanName) {
          
   
		MergedBeanDefinitionPostProcessor.super.resetBeanDefinition(beanName);
	}
}

然后编写 close 或者 shutdown 方法，若都编写则 close 方法生效。

@Component
public class XianJian {
          
   
	public void close() {
          
   
		System.out.println("销毁啦！！德玛西亚 close ");
	}

	public void shutdown() {
          
   
		System.out.println("销毁啦！！德玛西亚 shutdown ");
	}
}

最后两种骚操作 源码如下，小伙伴们可以琢磨琢磨~ org.springframework.beans.factory.support.DisposableBeanAdapter#inferDestroyMethodIfNecessary

private static String inferDestroyMethodIfNecessary(Object bean, RootBeanDefinition beanDefinition) {
          
   
		String destroyMethodName = beanDefinition.resolvedDestroyMethodName;
		if (destroyMethodName == null) {
          
   
			destroyMethodName = beanDefinition.getDestroyMethodName();
			boolean autoCloseable = (bean instanceof AutoCloseable);
			if (AbstractBeanDefinition.INFER_METHOD.equals(destroyMethodName) ||
					(destroyMethodName == null && autoCloseable)) {
          
   
				// Only perform destroy method inference in case of the bean
				// not explicitly implementing the DisposableBean interface
				destroyMethodName = null;
				if (!(bean instanceof DisposableBean)) {
          
   
					if (autoCloseable) {
          
   
						destroyMethodName = CLOSE_METHOD_NAME;
					}
					else {
          
   
						try {
          
   
							destroyMethodName = bean.getClass().getMethod(CLOSE_METHOD_NAME).getName();
						}
						catch (NoSuchMethodException ex) {
          
   
							try {
          
   
								destroyMethodName = bean.getClass().getMethod(SHUTDOWN_METHOD_NAME).getName();
							}
							catch (NoSuchMethodException ex2) {
          
   
								// no candidate destroy method found
							}
						}
					}
				}
			}
			beanDefinition.resolvedDestroyMethodName = (destroyMethodName != null ? destroyMethodName : "");
		}
		return (StringUtils.hasLength(destroyMethodName) ? destroyMethodName : null);
	}

感谢笔芯ꔛꕤ