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kill -9 pid ???
kill可将指定的信息送至程序。预设的信息为SIGTERM(15),可将指定程序终止。若仍无法终止该程序,可使用SIGKILL(9)信息尝试强制删除程序。程序或工作的编号可利用ps指令或jobs指令查看(这段话来自菜鸟教程)。讲的这个复杂,简单点来说就是用来杀死linux中的进程,啥?你问我啥是进程?请自行百度。
我相信很多人都用过kill -9 pid 这个命令,彻底杀死进程的意思,一般情况我们使用它没有上面问题,但是在我们项目中使用它就有可能存在致命的问题。
kill -9 pid 带来的问题
由于kill -9 属于暴力删除,所以会给程序带来比较严重的后果,那究竟会带来什么后果呢?举个栗子:转账功能,再给两个账户进行加钱扣钱的时候突然断电了?这个时候会发生什么事情?对于InnoDB存储引擎来说,没有什么损失,因为它支持事务,但是对于MyISAM引擎来说那简直就是灾难,为什么?假如给A账户扣了钱,现在需要将B账户加钱,这个时候停电了,就会造成,A的钱被扣了,但是B没有拿到这笔钱,这在生产环境是绝对不允许的,kill -9 相当于突然断电的效果。
当然了,像转账这种,肯定不是使用MyISAM引擎,但是如今分布式火了起来,跨服务转账已经是很平常的事情,这种时候如果使用kill -9 去停止服务,那就不是你的事务能保证数据的准确性了,这个时候你可能会想到分布式事务,这个世界上没有绝对的安全系统或者架构,分布式事务也是一样,他也会存在问题,概率很小,如果一旦发生,损失有可能是无法弥补的,所以一定不能使用kill -9 去停止服务,因为你不知道他会造成什么后果。
在MyISAM引擎中表现的更明显,比如用户的信息由两张表维护,管理员修改用户信息的时候需要修改两张表,但由于你的kill -9 暴力结束项目,导致只修改成功了一张表,这也会导致数据的不一致性,这是小事,因为大不了再修改一次,但是金钱、合同这些重要的信息如果由于你的暴力删除导致错乱,我觉得可能比删库跑路还严重,至少删库还能恢复,你这个都不知道错在哪里。
那我们应该怎么结束项目呢?
其实java给我们提供了结束项目的功能,比如:tomcat可以使用shutdown.bat/shutdown.sh进行优雅结束。
什么叫优雅结束?
“
第一步:停止接收请求和内部线程。第二步:判断是否有线程正在执行。
第三步:等待正在执行的线程执行完毕。
第四步:停止容器。
”
以上四步才是正常的结束流程,那springboot怎么正常结束服务呢?下面我介绍几种正常结束服务的方案,请拿好小本本做好笔记。优雅结束服务
kill -15 pid 这种方式也会比较优雅的结束进程(项目),使用他的时候需要慎重,为什么呢?我们来看个例子我写了一个普通的controller方法做测试
@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”; } 1234567891011 代码很简单,打印:test — start之后让让程序休眠100秒,然后再打印:test — end,在线程休眠中我们使用kill -15 pid来结束这个进程,你们猜 test — end会被打印吗?application.yml
server:
port: 9988 12 启动项目sudo mvn spring-boot:run
1 这是maven启动springboot项目的方式找到项目的进程id
sudo ps -ef |grep shutdown
1这个就是项目的进程号,接下来我们先测试test接口,让线程进入休眠状态,然后再使用kill -15 14086停止项目
sudo curl 127.0.0.1:9988/test
1 回到项目日志sudo kill -15 14086
1 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 C o n n e c t i o n H a n d l e r . p r o c e s s ( A b s t r a c t P r o t o c o l . j a v a : 868 ) a t o r g . a p a c h e . t o m c a t . u t i l . n e t . N i o E n d p o i n t ConnectionHandler.process(AbstractProtocol.java:868) at org.apache.tomcat.util.net.NioEndpoint ConnectionHandler.process(AbstractProtocol.java:868)atorg.apache.tomcat.util.net.NioEndpointSocketProcessor.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 W o r k e r . r u n ( T h r e a d P o o l E x e c u t o r . j a v a : 624 ) a t o r g . a p a c h e . t o m c a t . u t i l . t h r e a d s . T a s k T h r e a d Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread Worker.run(ThreadPoolExecutor.java:624)atorg.apache.tomcat.util.threads.TaskThreadWrappingRunnable.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 exceptionjava.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 C o n n e c t i o n H a n d l e r . p r o c e s s ( A b s t r a c t P r o t o c o l . j a v a : 868 ) [ t o m c a t − e m b e d − c o r e − 9.0.33. j a r : 9.0.33 ] a t o r g . a p a c h e . t o m c a t . u t i l . n e t . N i o E n d p o i n t ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.33.jar:9.0.33] at org.apache.tomcat.util.net.NioEndpoint ConnectionHandler.process(AbstractProtocol.java:868)[tomcat−embed−core−9.0.33.jar:9.0.33]atorg.apache.tomcat.util.net.NioEndpointSocketProcessor.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 W o r k e r . r u n ( T h r e a d P o o l E x e c u t o r . j a v a : 624 ) [ n a : 1.8. 0 2 42 ] a t o r g . a p a c h e . t o m c a t . u t i l . t h r e a d s . T a s k T h r e a d Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_242] at org.apache.tomcat.util.threads.TaskThread Worker.run(ThreadPoolExecutor.java:624)[na:1.8.0242]atorg.apache.tomcat.util.threads.TaskThreadWrappingRunnable.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]123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112
居然报错了,但是test — end是打印出来了,为什么会报错呢?这就和sleep这个方法有关了,在线程休眠期间,当调用线程的interrupt方法的时候会导致sleep抛出异常,这里很明显就是kill -15 这个命令会让程序马上调用线程的interrupt方法,目的是为了让线程停止,虽然让线程停止,但线程什么时候停止还是线程自己说的算,这就是为什么我们还能看到:test — end的原因。
ConfigurableApplicationContext colse
我们先看怎么实现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;@Overridepublic 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";}/** * 停机 */@PostMapping(value = "shutdown")public void shutdown(){ ConfigurableApplicationContext cyx = (ConfigurableApplicationContext) context; cyx.close();}
}
1234567891011121314151617181920212223242526272829303132333435363738394041424344 重点在:cyx.close();,为什么他能停止springboot项目呢?请看源码public void close() {
synchronized(this.startupShutdownMonitor) { this.doClose(); if (this.shutdownHook != null) { try { Runtime.getRuntime().removeShutdownHook(this.shutdownHook); } catch (IllegalStateException var4) { } }}}
123456789101112
程序在启动的时候向jvm注册了一个关闭钩子,我们在执行colse方法的时候会删除这个关闭钩子,jvm就会知道这是需要停止服务。我们看测试结果图片图片很明显,他也出发了线程的interrupt方法导致线程报错,原理和kill -15差不多。
actuator
这种方式是通过引入依赖的方式停止服务,actuator提供了很多接口,比如健康检查,基本信息等等,我们也可以使用他来优雅的停机。引入依赖
org.springframework.boot spring-boot-starter-actuator12345
application.ymlserver:
port: 9988management:
endpoints: web: exposure: include: shutdown endpoint: shutdown: enabled: true server: port: 8888 12345678910111213 我这里对actuator的接口重新给定了一个接口,这样可提高安全性,下面我们来测试一下@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”; } 1234567891011 在请求test途中停止服务1.新增停止springboot服务类: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 {
private volatile Connector connector;private final int waitTime = 10;@Overridepublic void customize(Connector connector) { this.connector = connector;}@Overridepublic 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("请尝试暴力关闭"); } } catch (InterruptedException ex) { System.out.println("异常了"); Thread.currentThread().interrupt(); } }}
}
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2.在启动类中加入beanpackage 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();}@Beanpublic ElegantShutdownConfig elegantShutdownConfig() { return new ElegantShutdownConfig();}@Beanpublic ServletWebServerFactory servletContainer() { TomcatServletWebServerFactory tomcat = new TomcatServletWebServerFactory(); tomcat.addConnectorCustomizers(elegantShutdownConfig()); return tomcat;}
}
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这样我们就配置好了,我们再来测试一遍,test的接口还是休眠10秒那可能你会有疑问了,jvm没有立即停止,那这个时候在有请求会发生什么呢?如果关闭的时候有新的请求,服务将不在接收此请求。
数据备份操作
如果我想在服务停止的时候做点备份操作啥的,应该怎么做呢?其实很简单在你要执行的方法上添加一个注解即可:@PreDestroy“
Destroy:消灭、毁灭 pre:前缀缩写”
所以合在一起的意思就是在容器停止之前执行一次,你可以在这里面做备份操作,也可以做记录停机时间等。新增服务停止备份工具类:DataBackupConfig.java
package com.ymy.config;
import org.springframework.context.annotation.Configuration;
import javax.annotation.PreDestroy;
@Configuration
public class DataBackupConfig {@PreDestroypublic void backData(){ System.out.println("正在备份数据。。。。。。。。。。。");}
}
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