前言

大家好，這里是浩道Linux，主要給大家分享Linux、Python、網(wǎng)絡(luò)通信、網(wǎng)絡(luò)安全等相關(guān)的IT知識(shí)平臺(tái)。

相信不少Linux運(yùn)維小伙伴在實(shí)際運(yùn)維中經(jīng)常會(huì)用到kill -9 進(jìn)程ID 這個(gè)命令來(lái)干掉程序。實(shí)際真的合理嗎，今天就讓我們一起來(lái)看看為什么技術(shù)牛人都不建議用kill -9關(guān)閉程序，看看該命令背后是咋樣的！

正文

kill -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。

kill -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)行加錢扣錢的時(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，現(xiàn)在需要將B賬戶加錢，這個(gè)時(shí)候停電了，就會(huì)造成，A的錢被扣了，但是B沒(méi)有拿到這筆錢，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、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。

優(yōu)雅結(jié)束服務(wù)

kill -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")
publicStringtest(){
log.info("test---start");
try{
Thread.sleep(100000);
}catch(InterruptedExceptione){
e.printStackTrace();
}
log.info("test---end");
return"test";
}
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代碼很簡(jiǎn)單，打?。簍est — 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？

application.yml

server:
port:9988
12

啟動(dòng)項(xiàng)目

sudo mvn spring-boot:run
1

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
1

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
1

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
1

回到日志

2020-04-2410:53:14.939INFO14086---[nio-9988-exec-1]com.ymy.controller.TestController:test---start
2020-04-2410:54:02.450INFO14086---[extShutdownHook]o.s.s.concurrent.ThreadPoolTaskExecutor:ShuttingdownExecutorService'applicationTaskExecutor'
java.lang.InterruptedException:sleepinterrupted
atjava.lang.Thread.sleep(NativeMethod)
atcom.ymy.controller.TestController.test(TestController.java:26)
atsun.reflect.NativeMethodAccessorImpl.invoke0(NativeMethod)
atsun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
atsun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
atjava.lang.reflect.Method.invoke(Method.java:498)
atorg.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190)
atorg.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
atorg.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105)
atorg.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879)
atorg.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793)
atorg.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
atorg.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
atorg.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
atorg.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
atorg.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
atjavax.servlet.http.HttpServlet.service(HttpServlet.java:634)
atorg.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
atjavax.servlet.http.HttpServlet.service(HttpServlet.java:741)
atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
atorg.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
atorg.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
atorg.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
atorg.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
atorg.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
atorg.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:109)
atorg.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
atorg.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
atorg.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
atorg.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
atorg.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
atorg.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
atorg.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
atorg.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
atorg.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
atorg.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
atorg.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
atorg.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373)
atorg.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
atorg.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
atorg.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1594)
atorg.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
atjava.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
atjava.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
atorg.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
atjava.lang.Thread.run(Thread.java:748)
2020-04-2410:54:04.574INFO14086---[nio-9988-exec-1]com.ymy.controller.TestController:test---end
2020-04-2410:54:04.610ERROR14086---[nio-9988-exec-1]o.s.web.servlet.HandlerExecutionChain:HandlerInterceptor.afterCompletionthrewexception

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

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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。

ConfigurableApplicationContext colse

我們先看怎么實(shí)現(xiàn)

packagecom.ymy.controller;

importlombok.extern.slf4j.Slf4j;
importorg.springframework.beans.BeansException;
importorg.springframework.context.ApplicationContext;
importorg.springframework.context.ApplicationContextAware;
importorg.springframework.context.ConfigurableApplicationContext;
importorg.springframework.web.bind.annotation.GetMapping;
importorg.springframework.web.bind.annotation.PostMapping;
importorg.springframework.web.bind.annotation.RestController;

@RestController
@Slf4j
publicclassTestControllerimplementsApplicationContextAware{

privateApplicationContextcontext;

@Override
publicvoidsetApplicationContext(ApplicationContextapplicationContext)throwsBeansException{
this.context=applicationContext;
}


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

/**
*停機(jī)
*/
@PostMapping(value="shutdown")
publicvoidshutdown(){
ConfigurableApplicationContextcyx=(ConfigurableApplicationContext)context;
cyx.close();
}
}
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重點(diǎn)在：cyx.close();，為什么他能停止springboot項(xiàng)目呢？請(qǐng)看源碼

publicvoidclose(){
synchronized(this.startupShutdownMonitor){
this.doClose();
if(this.shutdownHook!=null){
try{
Runtime.getRuntime().removeShutdownHook(this.shutdownHook);
}catch(IllegalStateExceptionvar4){
}
}

}
}
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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，他也觸發(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。

actuator

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

org.springframework.boot
spring-boot-starter-actuator


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)
publicStringtest(){
System.out.println("test---start");
try{
Thread.sleep(10000);
}catch(InterruptedExceptione){
e.printStackTrace();
}
System.out.println("test---end");
return"hello";
}
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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。

1.新增停止springboot服務(wù)類：ElegantShutdownConfig.java

packagecom.ymy.config;

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

importjava.util.concurrent.Executor;
importjava.util.concurrent.ThreadPoolExecutor;
importjava.util.concurrent.TimeUnit;

publicclassElegantShutdownConfigimplementsTomcatConnectorCustomizer,ApplicationListener{

privatevolatileConnectorconnector;
privatefinalintwaitTime=10;

@Override
publicvoidcustomize(Connectorconnector){
this.connector=connector;
}

@Override
publicvoidonApplicationEvent(ContextClosedEventevent){
connector.pause();
Executorexecutor=connector.getProtocolHandler().getExecutor();
if(executorinstanceofThreadPoolExecutor){
try{
ThreadPoolExecutorthreadPoolExecutor=(ThreadPoolExecutor)executor;
threadPoolExecutor.shutdown();
if(!threadPoolExecutor.awaitTermination(waitTime,TimeUnit.SECONDS)){
System.out.println("請(qǐng)嘗試暴力關(guān)閉");
}
}catch(InterruptedExceptionex){
System.out.println("異常了");
Thread.currentThread().interrupt();
}
}

}
}

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2.在啟動(dòng)類中加入bean

packagecom.ymy;

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

importjava.util.concurrent.Executor;
importjava.util.concurrent.ThreadPoolExecutor;
importjava.util.concurrent.TimeUnit;

@SpringBootApplication
publicclassShutdownServerApplication{

publicstaticvoidmain(String[]args){
ConfigurableApplicationContextrun=SpringApplication.run(ShutdownServerApplication.class,args);
run.registerShutdownHook();
}


@Bean
publicElegantShutdownConfigelegantShutdownConfig(){
returnnewElegantShutdownConfig();
}

@Bean
publicServletWebServerFactoryservletContainer(){
TomcatServletWebServerFactorytomcat=newTomcatServletWebServerFactory();
tomcat.addConnectorCustomizers(elegantShutdownConfig());
returntomcat;
}
}

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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。

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

packagecom.ymy.config;

importorg.springframework.context.annotation.Configuration;

importjavax.annotation.PreDestroy;

@Configuration
publicclassDataBackupConfig{

@PreDestroy
publicvoidbackData(){

System.out.println("正在備份數(shù)據(jù)。。。。。。。。。。。");
}
}
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我們?cè)賮?lái)測(cè)試然后打印控制臺(tái)日志：

審核編輯：湯梓紅