點(diǎn)擊上方 Java學(xué)習(xí)之道，選擇設(shè)為星標(biāo)

來(lái)源: blog.csdn.net/qq_33220089
作者: 流行007

Part1kill -9 pid ？？？

kill可將指定的信息送至程序。預(yù)設(shè)的信息為SIGTERM(15)，可將指定程序終止。若仍無(wú)法終止該程序，可使用SIGKILL(9)信息嘗試強(qiáng)制刪除程序。程序或工作的編號(hào)可利用ps指令或jobs指令查看（這段話來(lái)自菜鳥(niǎo)教程）。

講的這個(gè)復(fù)雜，簡(jiǎn)單點(diǎn)來(lái)說(shuō)就是用來(lái)殺死linux中的進(jìn)程，啥？你問(wèn)我啥是進(jìn)程？請(qǐng)自行百度。

我相信很多人都用過(guò)kill -9 pid這個(gè)命令，徹底殺死進(jìn)程的意思，一般情況我們使用它沒(méi)有上面問(wèn)題，但是在我們項(xiàng)目中使用它就有可能存在致命的問(wèn)題。

Part2kill -9 pid 帶來(lái)的問(wèn)題

由于kill -9 屬于暴力刪除，所以會(huì)給程序帶來(lái)比較嚴(yán)重的后果，那究竟會(huì)帶來(lái)什么后果呢？

舉個(gè)栗子：轉(zhuǎn)賬功能，再給兩個(gè)賬戶進(jìn)行加錢(qián)扣錢(qián)的時(shí)候突然斷電了？這個(gè)時(shí)候會(huì)發(fā)生什么事情？對(duì)于InnoDB存儲(chǔ)引擎來(lái)說(shuō)，沒(méi)有什么損失，因?yàn)樗С质聞?wù)，但是對(duì)于MyISAM引擎來(lái)說(shuō)那簡(jiǎn)直就是災(zāi)難，為什么？假如給A賬戶扣了錢(qián)，現(xiàn)在需要將B賬戶加錢(qián)，這個(gè)時(shí)候停電了，就會(huì)造成，A的錢(qián)被扣了，但是B沒(méi)有拿到這筆錢(qián)，這在生產(chǎn)環(huán)境是絕對(duì)不允許的，kill -9 相當(dāng)于突然斷電的效果。

當(dāng)然了，像轉(zhuǎn)賬這種，肯定不是使用MyISAM引擎，但是如今分布式火了起來(lái)，跨服務(wù)轉(zhuǎn)賬已經(jīng)是很平常的事情，這種時(shí)候如果使用kill -9 去停止服務(wù)，那就不是你的事務(wù)能保證數(shù)據(jù)的準(zhǔn)確性了，這個(gè)時(shí)候你可能會(huì)想到分布式事務(wù)，這個(gè)世界上沒(méi)有絕對(duì)的安全系統(tǒng)或者架構(gòu)，分布式事務(wù)也是一樣，他也會(huì)存在問(wèn)題，概率很小，如果一旦發(fā)生，損失有可能是無(wú)法彌補(bǔ)的，所以一定不能使用kill -9 去停止服務(wù)，因?yàn)槟悴恢浪麜?huì)造成什么后果。

在MyISAM引擎中表現(xiàn)的更明顯，比如用戶的信息由兩張表維護(hù)，管理員修改用戶信息的時(shí)候需要修改兩張表，但由于你的kill -9 暴力結(jié)束項(xiàng)目，導(dǎo)致只修改成功了一張表，這也會(huì)導(dǎo)致數(shù)據(jù)的不一致性，這是小事，因?yàn)榇蟛涣嗽傩薷囊淮?，但是金錢(qián)、合同這些重要的信息如果由于你的暴力刪除導(dǎo)致錯(cuò)亂，我覺(jué)得可能比刪庫(kù)跑路還嚴(yán)重，至少刪庫(kù)還能恢復(fù)，你這個(gè)都不知道錯(cuò)在哪里。

那我們應(yīng)該怎么結(jié)束項(xiàng)目呢？

其實(shí)java給我們提供了結(jié)束項(xiàng)目的功能，比如：tomcat可以使用shutdown.bat/shutdown.sh進(jìn)行優(yōu)雅結(jié)束。

什么叫優(yōu)雅結(jié)束？

第一步：停止接收請(qǐng)求和內(nèi)部線程。

第二步：判斷是否有線程正在執(zhí)行。

第三步：等待正在執(zhí)行的線程執(zhí)行完畢。

第四步：停止容器。

以上四步才是正常的結(jié)束流程，那springboot怎么正常結(jié)束服務(wù)呢？下面我介紹幾種正常結(jié)束服務(wù)的方案，請(qǐng)拿好小本本做好筆記。

Part3優(yōu)雅結(jié)束服務(wù)

1kill -15 pid

這種方式也會(huì)比較優(yōu)雅的結(jié)束進(jìn)程（項(xiàng)目），使用他的時(shí)候需要慎重，為什么呢？我們來(lái)看個(gè)例子

我寫(xiě)了一個(gè)普通的controller方法做測(cè)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";
}

代碼很簡(jiǎn)單，打印：test — start之后讓讓程序休眠100秒，然后再打?。簍est — end，在線程休眠中我們使用kill -15 pid來(lái)結(jié)束這個(gè)進(jìn)程，你們猜 test — end會(huì)被打印嗎？

2application.yml

server:
  port: 9988

3啟動(dòng)項(xiàng)目

sudo mvn spring-boot:run

這是maven啟動(dòng)springboot項(xiàng)目的方式

看到這個(gè)就代表項(xiàng)目啟動(dòng)成了

找到項(xiàng)目的進(jìn)程id

sudo ps -ef |grep shutdown

這個(gè)就是項(xiàng)目的進(jìn)程號(hào)，接下來(lái)我們先測(cè)試test接口，讓線程進(jìn)入休眠狀態(tài)，然后再使用kill -15 14086停止項(xiàng)目

sudo curl 127.0.0.1:9988/test

回到項(xiàng)目日志我們發(fā)現(xiàn)請(qǐng)求已經(jīng)到達(dá)服務(wù)，并且線程已經(jīng)成功進(jìn)入休眠，現(xiàn)在我們kill -15 14086結(jié)束進(jìn)程

sudo kill -15 14086

回到日志

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]

居然報(bào)錯(cuò)了，但是test — end是打印出來(lái)了，為什么會(huì)報(bào)錯(cuò)呢？這就和sleep這個(gè)方法有關(guān)了，在線程休眠期間，當(dāng)調(diào)用線程的interrupt方法的時(shí)候會(huì)導(dǎo)致sleep拋出異常，這里很明顯就是kill -15 這個(gè)命令會(huì)讓程序馬上調(diào)用線程的interrupt方法，目的是為了讓線程停止，雖然讓線程停止，但線程什么時(shí)候停止還是線程自己說(shuō)的算，這就是為什么我們還能看到：test — end的原因。

4ConfigurableApplicationContext colse

我們先看怎么實(shí)現(xiàn)

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(jī)
     */
    @PostMapping(value = "shutdown")
    public void shutdown(){
        ConfigurableApplicationContext cyx = (ConfigurableApplicationContext) context;
        cyx.close();
    }
}

重點(diǎn)在：cyx.close();，為什么他能停止springboot項(xiàng)目呢？請(qǐng)看源碼

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

程序在啟動(dòng)的時(shí)候向jvm注冊(cè)了一個(gè)關(guān)閉鉤子，我們?cè)趫?zhí)行colse方法的時(shí)候會(huì)刪除這個(gè)關(guān)閉鉤子，jvm就會(huì)知道這是需要停止服務(wù)。

我們看測(cè)試結(jié)果

很明顯，他也出發(fā)了線程的interrupt方法導(dǎo)致線程報(bào)錯(cuò)，原理和kill -15差不多。

5actuator

這種方式是通過(guò)引入依賴的方式停止服務(wù)，actuator提供了很多接口，比如健康檢查，基本信息等等，我們也可以使用他來(lái)優(yōu)雅的停機(jī)。

引入依賴

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

application.yml

server:
  port: 9988

management:
  endpoints:
    web:
      exposure:
        include: shutdown
  endpoint:
    shutdown:
      enabled: true
  server:
    port: 8888

我這里對(duì)actuator的接口重新給定了一個(gè)接口，這樣可提高安全性，下面我們來(lái)測(cè)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";
}

在請(qǐng)求test途中停止服務(wù)我們發(fā)現(xiàn)發(fā)送停止服務(wù)請(qǐng)求之后還給我們返回了提示信息，很人性化，我們看看控制臺(tái)

test — end被執(zhí)行了，不過(guò)在停止線程池的時(shí)候還是調(diào)用了線程的interrupt方法，導(dǎo)致sleep報(bào)錯(cuò)，這三種方式都可以比較優(yōu)雅的停止springboot服務(wù)，如果我項(xiàng)目中存在線程休眠，我希望10秒以后再停止服務(wù)可以嗎？肯定是可以的，我們只需要稍微做點(diǎn)修改就可以了。

610秒以后再停止服務(wù)

1.新增停止springboot服務(wù)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(qǐng)嘗試暴力關(guān)閉");
        }
    } catch (InterruptedException ex) {
        System.out.println("異常了");
        Thread.currentThread().interrupt();
    }
  }
  }
}

2.在啟動(dòng)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;
  }
}

這樣我們就配置好了，我們?cè)賮?lái)測(cè)試一遍，test的接口還是休眠10秒我們發(fā)現(xiàn)這次沒(méi)有報(bào)錯(cuò)了，他是等待了一段時(shí)間之后再結(jié)束的線程池，這個(gè)時(shí)間就是我們?cè)贓legantShutdownConfig類中配置的waitTime。

那可能你會(huì)有疑問(wèn)了，jvm沒(méi)有立即停止，那這個(gè)時(shí)候在有請(qǐng)求會(huì)發(fā)生什么呢？如果關(guān)閉的時(shí)候有新的請(qǐng)求，服務(wù)將不在接收此請(qǐng)求。

Part4數(shù)據(jù)備份操作

如果我想在服務(wù)停止的時(shí)候做點(diǎn)備份操作啥的，應(yīng)該怎么做呢？其實(shí)很簡(jiǎn)單在你要執(zhí)行的方法上添加一個(gè)注解即可：@PreDestroy

Destroy：消滅、毀滅

pre:前綴縮寫(xiě) 所以合在一起的意思就是在容器停止之前執(zhí)行一次，你可以在這里面做備份操作，也可以做記錄停機(jī)時(shí)間等。

新增服務(wù)停止備份工具類：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(shù)據(jù)。。。。。。。。。。。");
  }
}

我們?cè)賮?lái)測(cè)試然后打印控制臺(tái)日志：

-- END --

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怎么關(guān)閉程序? 是用kill -9嗎?

Part1kill -9 pid ？？？