package com.wyf.service;

import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.Lifecycle;
import org.springframework.context.SmartLifecycle;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.stereotype.Component;

import javax.annotation.PreDestroy;

@Component
public class UserService implements DisposableBean, SmartLifecycle {

        boolean isRunning = false;
    
    
        @Override
        public void destroy() throws Exception {
            System.out.println(this.getClass().getSimpleName()+" is destroying.....");
        }
    
    
        @PreDestroy
        public void preDestory(){
            System.out.println(this.getClass().getSimpleName()+" is pre destory....");
        }
    
        @Override
        public void start() {
            System.out.println(this.getClass().getSimpleName()+" is start..");
            isRunning=true;
        }
    
        @Override
        public void stop() {
            System.out.println(this.getClass().getSimpleName()+" is stop...");
            isRunning=false;
        }
    
        @Override
        public boolean isRunning() {
            return isRunning;
        }

}

package com.wyf;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Application {
    public static void main(String[] args) {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");

    }
}

package com.wyf;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Application {
    public static void main(String[] args) {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
        //添加一個關閉鉤子，用于觸發(fā)對象銷毀操作
        context.registerShutdownHook();

        context.close();
    }
}

@Override
public void registerShutdownHook() {
   if (this.shutdownHook == null) {
      // No shutdown hook registered yet.
      this.shutdownHook = new Thread(SHUTDOWN_HOOK_THREAD_NAME) {
         @Override
         public void run() {
            synchronized (startupShutdownMonitor) {
               doClose();
            }
         }
      };
      Runtime.getRuntime().addShutdownHook(this.shutdownHook);
   }
}

@Override
    public void close() {
        synchronized (this.startupShutdownMonitor) {
            doClose();
            // If we registered a JVM shutdown hook, we don't need it anymore now:
            // We've already explicitly closed the context.
            if (this.shutdownHook != null) {
                try {
                    Runtime.getRuntime().removeShutdownHook(this.shutdownHook);
                }
                catch (IllegalStateException ex) {
                    // ignore - VM is already shutting down
                }
            }
        }
    }

    @Override
    public void close() {
        synchronized (this.startupShutdownMonitor) {
            doClose();
            // If we registered a JVM shutdown hook, we don't need it anymore now:
            // We've already explicitly closed the context.
            if (this.shutdownHook != null) {
                try {
                    Runtime.getRuntime().removeShutdownHook(this.shutdownHook);
                }
                catch (IllegalStateException ex) {
                    // ignore - VM is already shutting down
                }
            }
        }
    }

    @SuppressWarnings("deprecation")
    protected void doClose() {
        // Check whether an actual close attempt is necessary...
        //判斷是否有必要執(zhí)行關閉操作
        //如果容器正在執(zhí)行中，并且以CAS的方式設置關閉標識成功，則執(zhí)行后續(xù)關閉操作，當然這個標識僅僅是標識，并沒有真正修改容器的狀態(tài)
        if (this.active.get() && this.closed.compareAndSet(false, true)) {
            if (logger.isDebugEnabled()) {
                logger.debug("Closing " + this);
            }

            if (!NativeDetector.inNativeImage()) {
                LiveBeansView.unregisterApplicationContext(this);
            }

            try {
                // Publish shutdown event.
                //發(fā)布容器關閉事件，通知所有監(jiān)聽器
                publishEvent(new ContextClosedEvent(this));
            }
            catch (Throwable ex) {
                logger.warn("Exception thrown from ApplicationListener handling ContextClosedEvent", ex);
            }

            // Stop all Lifecycle beans, to avoid delays during individual destruction.
            //如果存在bean實現(xiàn)的Lifecycle接口，則執(zhí)行onClose(),lifecycleProcessor會對所有Lifecycle進行分組然后分批執(zhí)行stop方法
            if (this.lifecycleProcessor != null) {
                try {
                    this.lifecycleProcessor.onClose();
                }
                catch (Throwable ex) {
                    logger.warn("Exception thrown from LifecycleProcessor on context close", ex);
                }
            }

            // Destroy all cached singletons in the context's BeanFactory.
            //銷毀所有緩存的單例bean
            destroyBeans();

            // Close the state of this context itself.
            //關閉bean工廠
            closeBeanFactory();

            // Let subclasses do some final clean-up if they wish...
            //為子類預留的方法允許子類去自定義一些銷毀操作
            onClose();

            // Reset local application listeners to pre-refresh state.
            //將本地應用程序偵聽器重置為預刷新狀態(tài)。
            if (this.earlyApplicationListeners != null) {
                this.applicationListeners.clear();
                this.applicationListeners.addAll(this.earlyApplicationListeners);
            }

            // Switch to inactive.
            //設置上下文到狀態(tài)為關閉狀態(tài)
            this.active.set(false);
        }
    }