springboot 优雅关闭

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springboot 优雅关闭

应用：停机升级服务时， 若仍有线程运行，可等待一段时间后关闭应用；若线程未执行完成关闭应用，输出相应提示

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示例

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config 层

GracefulShutDown

@Component
public class GracefulShutDown implements TomcatConnectorCustomizer,
        ApplicationListener<ContextClosedEvent> {

    private Logger logger= LoggerFactory.getLogger(GracefulShutDown.class);

    private Connector connector;

    @Override
    public void customize(Connector connector) {
        this.connector=connector;
    }

    @Override
    public void onApplicationEvent(ContextClosedEvent contextClosedEvent) {  //容器关闭之前调用
        this.connector.pause();
        Executor executor=this.connector.getProtocolHandler().getExecutor();

        if (executor instanceof ThreadPoolExecutor){
            ThreadPoolExecutor threadPoolExecutor=(ThreadPoolExecutor) executor;
            threadPoolExecutor.shutdown();  //若无线程运行，立即关闭线程池；若有线程运行则等待

            try {
                if (!threadPoolExecutor.awaitTermination(10, TimeUnit.SECONDS)){
                                            //等待10s，为false表示线程池没有关闭，随后强制关闭，此时正在执行的任务中断，只执行了一部分，控制台输出warn日志
                    logger.warn("10秒后线程未关闭，将强制关闭");
                }else {
                    System.out.println("线程池已关闭："+ LocalDateTime.now());
                }                           //为true，线程池已经关闭，任务执行完成
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

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controller 层

HelloController

@RestController
public class HelloController {

    @RequestMapping("/hello")
    public String hello(){
        try{
            Thread.sleep(2000);
        }catch (Exception e){
            System.out.println(e.getMessage());
        }

        return "hello world";
    }

    @RequestMapping("/hello2")
    public String hello2(){

        try{
            Thread.sleep(20000);
        }catch (Exception e){
            System.out.println(e.getMessage());
        }

        return "hello world";
    }
}

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使用测试

/hello

      

说明：ctrl+c时任务执行结束，线程池立即关闭

/hello2

      

说明：ctrl+c时任务没有执行结束，线程池没有立即关闭；等待10s后线程池强制关闭，任务没有执行完成，无返回结果