還在使用kill -9 pid結束spring boot項目嗎？那你太落後了

時間 2021-01-14

標籤 html java linux web 算法 spring shell apache 設計模式 tomcat 欄目 Spring 简体版

原文原文鏈接

歡迎微信搜索公衆號【java版web項目】獲取資源：java學習視頻/設計模式筆記/算法手冊/java項目html

kill -9 pid ？？？

kill可將指定的信息送至程序。預設的信息爲SIGTERM(15)，可將指定程序終止。若仍沒法終止該程序，可以使用SIGKILL(9)信息嘗試強制刪除程序。程序或工做的編號可利用ps指令或jobs指令查看（這段話來自菜鳥教程）。java

講的這個複雜，簡單點來講就是用來殺死linux中的進程，啥？你問我啥是進程？請自行百度。linux

我相信不少人都用過kill -9 pid 這個命令，完全殺死進程的意思，通常狀況咱們使用它沒有上面問題，可是在咱們項目中使用它就有可能存在致命的問題。web

kill -9 pid 帶來的問題

因爲kill -9 屬於暴力刪除，因此會給程序帶來比較嚴重的後果，那究竟會帶來什麼後果呢？算法

舉個栗子：轉帳功能，再給兩個帳戶進行加錢扣錢的時候忽然斷電了？這個時候會發生什麼事情？對於InnoDB存儲引擎來講，沒有什麼損失，由於它支持事務，可是對於MyISAM引擎來講那簡直就是災難，爲何？假如給A帳戶扣了錢，如今須要將B帳戶加錢，這個時候停電了，就會形成，A的錢被扣了，可是B沒有拿到這筆錢，這在生產環境是絕對不容許的，kill -9 至關於忽然斷電的效果。spring

固然了，像轉帳這種，確定不是使用MyISAM引擎，可是現在分佈式火了起來，跨服務轉帳已是很日常的事情，這種時候若是使用kill -9 去中止服務，那就不是你的事務能保證數據的準確性了，這個時候你可能會想到分佈式事務，這個世界上沒有絕對的安全系統或者架構，分佈式事務也是同樣，他也會存在問題，機率很小，若是一旦發生，損失有多是沒法彌補的，因此必定不能使用kill -9 去中止服務，由於你不知道他會形成什麼後果。shell

在MyISAM引擎中表現的更明顯，好比用戶的信息由兩張表維護，管理員修改用戶信息的時候須要修改兩張表，但因爲你的kill -9 暴力結束項目，致使只修改爲功了一張表，這也會致使數據的不一致性，這是小事，由於大不了再修改一次，可是金錢、合同這些重要的信息若是因爲你的暴力刪除致使錯亂，我以爲可能比刪庫跑路還嚴重，至少刪庫還能恢復，你這個都不知道錯在哪裏。apache

那咱們應該怎麼結束項目呢？設計模式

其實java給咱們提供告終束項目的功能，好比：tomcat可使用shutdown.bat/shutdown.sh進行優雅結束。tomcat

什麼叫優雅結束？

第一步：中止接收請求和內部線程。
第二步：判斷是否有線程正在執行。
第三步：等待正在執行的線程執行完畢。
第四步：中止容器。

以上四步纔是正常的結束流程，那springboot怎麼正常結束服務呢？下面我介紹幾種正常結束服務的方案，請拿好小本本作好筆記。

優雅結束服務

kill -15 pid

這種方式也會比較優雅的結束進程（項目），使用他的時候須要慎重，爲何呢？咱們來看個例子

我寫了一個普通的controller方法作測試

@GetMapping(value = "/test")
    public String test(){
        log.info("test --- start");
        try {
            Thread.sleep(100000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        log.info("test --- end");
        return "test";
    }
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代碼很簡單，打印：test — start以後讓讓程序休眠100秒，而後再打印：test — end，在線程休眠中咱們使用kill -15 pid來結束這個進程，大家猜 test — end會被打印嗎？

application.yml

server:
  port: 9988
12

啓動項目

sudo mvn spring-boot:run
1

這是maven啓動springboot項目的方式

看到這個就表明項目啓動成了

找到項目的進程id

sudo ps -ef |grep shutdown
1

這個就是項目的進程號，接下來咱們先測試test接口，讓線程進入休眠狀態，而後再使用kill -15 14086中止項目

sudo curl 127.0.0.1:9988/test
1

回到項目日誌

咱們發現請求已經到達服務，而且線程已經成功進入休眠，如今咱們kill -15 14086結束進程

sudo kill -15 14086
1

回到日誌

2020-04-24 10:53:14.939  INFO 14086 --- [nio-9988-exec-1] com.ymy.controller.TestController        : test --- start
2020-04-24 10:54:02.450  INFO 14086 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
java.lang.InterruptedException: sleep interrupted
    at java.lang.Thread.sleep(Native Method)
    at com.ymy.controller.TestController.test(TestController.java:26)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:109)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1594)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)
2020-04-24 10:54:04.574  INFO 14086 --- [nio-9988-exec-1] com.ymy.controller.TestController        : test --- end
2020-04-24 10:54:04.610 ERROR 14086 --- [nio-9988-exec-1] o.s.web.servlet.HandlerExecutionChain    : HandlerInterceptor.afterCompletion threw exception

java.lang.NullPointerException: null
    at org.springframework.boot.actuate.metrics.web.servlet.LongTaskTimingHandlerInterceptor.stopLongTaskTimers(LongTaskTimingHandlerInterceptor.java:123) ~[spring-boot-actuator-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.boot.actuate.metrics.web.servlet.LongTaskTimingHandlerInterceptor.afterCompletion(LongTaskTimingHandlerInterceptor.java:79) ~[spring-boot-actuator-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.web.servlet.HandlerExecutionChain.triggerAfterCompletion(HandlerExecutionChain.java:179) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.triggerAfterCompletion(DispatcherServlet.java:1427) [spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1060) [spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) [spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) [spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) [spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) [spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) [tomcat-embed-websocket-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) [spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) [spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:109) [spring-boot-actuator-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) [spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) [spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1594) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_242]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_242]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.33.jar:9.0.33]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_242]

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竟然報錯了，可是test — end是打印出來了，爲何會報錯呢？這就和sleep這個方法有關了，在線程休眠期間，當調用線程的interrupt方法的時候會致使sleep拋出異常，這裏很明顯就是kill -15 這個命令會讓程序立刻調用線程的interrupt方法，目的是爲了讓線程中止，雖然讓線程中止，但線程何時中止仍是線程本身說的算，這就是爲何咱們還能看到：test — end的緣由。

ConfigurableApplicationContext colse

咱們先看怎麼實現

package com.ymy.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@Slf4j
public class TestController  implements ApplicationContextAware {

    private  ApplicationContext  context;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.context = applicationContext;
    }


    @GetMapping(value = "/test")
    public String test(){
        log.info("test --- start");
        try {
            Thread.sleep(100000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        log.info("test --- end");
        return "test";
    }

    /**
     * 停機
     */
    @PostMapping(value = "shutdown")
    public void shutdown(){
        ConfigurableApplicationContext cyx = (ConfigurableApplicationContext) context;
        cyx.close();
    }
}
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重點在：cyx.close();，爲何他能中止springboot項目呢？請看源碼

public void close() {
        synchronized(this.startupShutdownMonitor) {
            this.doClose();
            if (this.shutdownHook != null) {
                try {
                    Runtime.getRuntime().removeShutdownHook(this.shutdownHook);
                } catch (IllegalStateException var4) {
                }
            }

        }
    }
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程序在啓動的時候向jvm註冊了一個關閉鉤子，咱們在執行colse方法的時候會刪除這個關閉鉤子，jvm就會知道這是須要中止服務。

咱們看測試結果

很明顯，他也出發了線程的interrupt方法致使線程報錯，原理和kill -15差很少。

actuator

這種方式是經過引入依賴的方式中止服務，actuator提供了不少接口，好比健康檢查，基本信息等等，咱們也可使用他來優雅的停機。

引入依賴

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

12345

application.yml

server:
  port: 9988

management:
  endpoints:
    web:
      exposure:
        include: shutdown
  endpoint:
    shutdown:
      enabled: true
  server:
    port: 8888
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我這裏對actuator的接口從新給定了一個接口，這樣可提升安全性，下面咱們來測試一下

@RequestMapping(value = "/test",method = RequestMethod.GET)
    public String test(){
        System.out.println("test --- start");
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("test --- end");
        return "hello";
    }
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在請求test途中中止服務

咱們發現發送中止服務請求以後還給咱們返回了提示信息，很人性化，咱們看看控制檯

test — end被執行了，不過在中止線程池的時候仍是調用了線程的interrupt方法，致使sleep報錯，這三種方式均可以比較優雅的中止springboot服務，若是我項目中存在線程休眠，我但願10秒之後再中止服務能夠嗎？確定是能夠的，咱們只須要稍微作點修改就能夠了。

1.新增中止springboot服務類：ElegantShutdownConfig.java

package com.ymy.config;

import org.apache.catalina.connector.Connector;
import org.springframework.boot.web.embedded.tomcat.TomcatConnectorCustomizer;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextClosedEvent;

import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ElegantShutdownConfig implements TomcatConnectorCustomizer, ApplicationListener<ContextClosedEvent> {

    private volatile Connector connector;
    private final int waitTime = 10;

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

    @Override
    public void onApplicationEvent(ContextClosedEvent event) {
        connector.pause();
        Executor executor = connector.getProtocolHandler().getExecutor();
        if (executor instanceof ThreadPoolExecutor) {
            try {
                ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
                threadPoolExecutor.shutdown();
                if (!threadPoolExecutor.awaitTermination(waitTime, TimeUnit.SECONDS)) {
                    System.out.println("請嘗試暴力關閉");
                }
            } catch (InterruptedException ex) {
                System.out.println("異常了");
                Thread.currentThread().interrupt();
            }
        }

    }
}

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2.在啓動類中加入bean

package com.ymy;

import com.ymy.config.ElegantShutdownConfig;
import lombok.extern.slf4j.Slf4j;
import org.apache.catalina.connector.Connector;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.embedded.tomcat.TomcatConnectorCustomizer;
import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
import org.springframework.boot.web.servlet.server.ServletWebServerFactory;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.event.ContextClosedEvent;

import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

@SpringBootApplication
public class ShutdownServerApplication {

    public static void main(String[] args) {
        ConfigurableApplicationContext run = SpringApplication.run(ShutdownServerApplication.class, args);
        run.registerShutdownHook();
    }


    @Bean
    public ElegantShutdownConfig elegantShutdownConfig() {
        return new ElegantShutdownConfig();
    }

    @Bean
    public ServletWebServerFactory servletContainer() {
        TomcatServletWebServerFactory tomcat = new TomcatServletWebServerFactory();
        tomcat.addConnectorCustomizers(elegantShutdownConfig());
        return tomcat;
    }
}

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這樣咱們就配置好了，咱們再來測試一遍，test的接口仍是休眠10秒

咱們發現此次沒有報錯了，他是等待了一段時間以後再結束的線程池，這個時間就是咱們在ElegantShutdownConfig類中配置的waitTime。

那可能你會有疑問了，jvm沒有當即中止，那這個時候在有請求會發生什麼呢？若是關閉的時候有新的請求，服務將不在接收此請求。

數據備份操做

若是我想在服務中止的時候作點備份操做啥的，應該怎麼作呢？其實很簡單在你要執行的方法上添加一個註解便可：@PreDestroy

Destroy：消滅、毀滅
pre:前綴縮寫

因此合在一塊兒的意思就是在容器中止以前執行一次，你能夠在這裏面作備份操做，也能夠作記錄停機時間等。

新增服務中止備份工具類：DataBackupConfig.java

package com.ymy.config;

import org.springframework.context.annotation.Configuration;

import javax.annotation.PreDestroy;

@Configuration
public class DataBackupConfig {

    @PreDestroy
    public  void backData(){

        System.out.println("正在備份數據。。。。。。。。。。。");
    }
}
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咱們再來測試而後打印控制檯日誌：