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          發(fā)現(xiàn)誰用 kill -9 關(guān)閉程序就開除!

          共 23803字,需瀏覽 48分鐘

           ·

          2024-06-05 08:29

          作者:流星007
          來源:blog.csdn.net/qq_33220089/article/details/105708331

          # 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。程序或工作的編號可利用ps指令或jobs指令查看(這段話來自菜鳥教程)。

          講的這個(gè)復(fù)雜,簡單點(diǎn)來說就是用來殺死linux中的進(jìn)程,啥?你問我啥是進(jìn)程?請自行百度。

          我相信很多人都用過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有上面問題,但是在我們項(xiàng)目中使用它就有可能存在致命的問題。
          
             

          # kill -9 pid 帶來的問題

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

          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)候會發(fā)生什么事情?對于InnoDB存儲引擎來說,沒有什么損失,因?yàn)樗С质聞?wù),但是對于MyISAM引擎來說那簡直就是災(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,就會造成,A的錢被扣了,但是B沒有拿到這筆錢,這在生產(chǎn)環(huán)境是絕對不允許的,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,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)候你可能會想到分布式事務(wù),這個(gè)世界上沒有絕對的安全系統(tǒng)或者架構(gòu),分布式事務(wù)也是一樣,他也會存在問題,概率很小,如果一旦發(fā)生,損失有可能是無法彌補(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斐墒裁春蠊?/span>

          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)榇蟛涣嗽傩薷囊淮危墙疱X、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,我覺得可能比刪庫跑路還嚴(yán)重,至少刪庫還能恢復(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?
          我們來看個(gè)例子

          我寫了一個(gè)普通的controller方法做測試
              
          @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"; }

          代碼很簡單,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來結(jié)束這個(gè)進(jìn)程,你們猜 test — end會被打印嗎?
              
          application.ymlserver: port: 9988
          啟動項(xiàng)目

              
          sudo mvn spring-boot:run

          這是maven啟動springboot項(xiàng)目的方式


          看到這個(gè)就代表項(xiàng)目啟動成了

          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,接下來我們先測試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 --- start2020-04-24 10:54:02.450 INFO 14086 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'java.lang.InterruptedException: sleep interruptedat 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 --- end2020-04-24 10:54:04.610 ERROR 14086 --- [nio-9988-exec-1] o.s.web.servlet.HandlerExecutionChain : HandlerInterceptor.afterCompletion threw exceptionjava.lang.NullPointerException: nullat 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是打印出來了,為什么會報(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)候會導(dǎo)致sleep拋出異常,這里很明顯就是kill -15 這個(gè)命令會讓程序馬上調(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)
              
          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@Slf4jpublic 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) { } } } }
          程序在啟動的時(shí)候向jvm注冊了一個(gè)關(guān)閉鉤子,我們在執(zhí)行colse方法的時(shí)候會刪除這個(gè)關(guān)閉鉤子,jvm就會知道這是需要停止服務(wù)。

          我們看測試結(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。

          # actuator

          這種方式是通過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: 9988management: endpoints: web: exposure: include: shutdown endpoint: shutdown: enabled: true server: port: 8888
          我這里對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"; }
          在請求test途中停止服務(wù)


          我們發(fā)現(xiàn)發(fā)送停止服務(wù)請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



          test — end被執(zhí)行了,不過在停止線程池的時(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
              
          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(guān)閉"); } } catch (InterruptedException ex) { System.out.println("異常了"); Thread.currentThread().interrupt(); } } }}
          2.在啟動類中加入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;@SpringBootApplicationpublic 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,我們再來測試一遍,test的接口還是休眠10秒


          我們發(fā)現(xiàn)這次沒有報(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)間就是我們在ElegantShutdownConfig類中配置的waitTime。

          那可能你會有疑問了,jvm沒有立即停止,那這個(gè)時(shí)候在有請求會發(fā)生什么呢?如果關(guān)閉的時(shí)候有新的請求,服務(wù)將不在接收此請求。

          # 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

          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;@Configurationpublic class DataBackupConfig { @PreDestroy public void backData(){ System.out.println("正在備份數(shù)據(jù)。。。。。。。。。。。"); }}
          我們再來測試然后打印控制臺日志:



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