CTO 说了，再发现谁用 kill -9 关闭程序就开除
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。若仍没法终止该程序，可以使用SIGKILL(9)信息尝试强制删除程序。程序或工做的编号可利用ps指令或jobs指令查看。java
讲的这个复杂，简单点来讲就是用来杀死linux中的进程，啥？你问我啥是进程？请自行百度。linux
我相信不少人都用过kill -9 pid 这个命令，完全杀死进程的意思，通常状况咱们使用它没有上面问题，可是在咱们项目中使用它就有可能存在致命的问题。web
kill -9 pid 带来的问题
因为kill -9 属于暴力删除，因此会给程序带来比较严重的后果，那究竟会带来什么后果呢？spring
举个栗子：转帐功能，再给两个帐户进行加钱扣钱的时候忽然断电了？这个时候会发生什么事情？对于InnoDB存储引擎来讲，没有什么损失，由于它支持事务，可是对于MyISAM引擎来讲那简直就是灾难，为何？假如给A帐户扣了钱，如今须要将B帐户加钱，这个时候停电了，就会形成，A的钱被扣了，可是B没有拿到这笔钱，这在生产环境是绝对不容许的，kill -9 至关于忽然断电的效果。apache
固然了，像转帐这种，确定不是使用MyISAM引擎，可是现在分布式火了起来，跨服务转帐已是很日常的事情，这种时候若是使用kill -9 去中止服务，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，分布式事务也是同样，他也会存在问题，几率很小，若是一旦发生，损失有多是没法弥补的，因此必定不能使用kill -9 去中止服务，由于你不知道他会形成什么后果。tomcat
在MyISAM引擎中表现的更明显，好比用户的信息由两张表维护，管理员修改用户信息的时候须要修改两张表，但因为你的kill -9 暴力结束项目，致使只修改为功了一张表，这也会致使数据的不一致性，这是小事，由于大不了再修改一次，可是金钱、合同这些重要的信息若是因为你的暴力删除致使错乱，我以为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。安全
那咱们应该怎么结束项目呢？springboot
其实java给咱们提供告终束项目的功能，好比：tomcat可使用shutdown.bat/shutdown.sh进行优雅结束。websocket
什么叫优雅结束？架构
第一步：中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：中止容器。
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，请拿好小本本作好笔记。
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），使用他的时候须要慎重，为何呢？咱们来看个例子
我写了一个普通的controller方法作测试
@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";
}
代码很简单，打印：test — start以后让让程序休眠100秒，而后再打印：test — end，在线程休眠中咱们使用kill -15 pid来结束这个进程，大家猜 test — end会被打印吗？
application.yml server: port: 9988
启动项目
sudo mvn spring-boot:run
这是maven启动springboot项目的方式
看到这个就表明项目启动成了
找到项目的进程id
sudo ps -ef |grep shutdown
这个就是项目的进程号，接下来咱们先测试test接口，让线程进入休眠状态，而后再使用kill -15 14086中止项目
sudo curl 127.0.0.1:9988/test
回到项目日志
咱们发现请求已经到达服务，而且线程已经成功进入休眠，如今咱们kill -15 14086结束进程
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]
竟然报错了，可是test — end是打印出来了，为何会报错呢？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方法的时候会致使sleep抛出异常，这里很明显就是kill -15 这个命令会让程序立刻调用线程的interrupt方法，目的是为了让线程中止，虽然让线程中止，但线程何时中止仍是线程本身说的算，这就是为何咱们还能看到：test — end的缘由。
ConfigurableApplicationContext colse
咱们先看怎么实现
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;
@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";
}
/**
* 停机
*/
@PostMapping(value = "shutdown")
public void shutdown(){
ConfigurableApplicationContext cyx = (ConfigurableApplicationContext) context;
cyx.close();
}
}
重点在：cyx.close();，为何他能中止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) {
}
}
}
}
程序在启动的时候向jvm注册了一个关闭钩子，咱们在执行colse方法的时候会删除这个关闭钩子，jvm就会知道这是须要中止服务。
咱们看测试结果
很明显，他也触发了线程的interrupt方法致使线程报错，原理和kill -15差很少。
actuator
这种方式是经过引入依赖的方式中止服务，actuator提供了不少接口，好比健康检查，基本信息等等，咱们也可使用他来优雅的停机。
引入依赖
<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
我这里对actuator的接口从新给定了一个接口，这样可提升安全性，下面咱们来测试一下
@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";
}
在请求test途中中止服务
咱们发现发送中止服务请求以后还给咱们返回了提示信息，很人性化，咱们看看控制台
test — end被执行了，不过在中止线程池的时候仍是调用了线程的interrupt方法，致使sleep报错，这三种方式均可以比较优雅的中止springboot服务，若是我项目中存在线程休眠，我但愿10秒之后再中止服务能够吗？确定是能够的，咱们只须要稍微作点修改就能够了。
- 1.新增中止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<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("请尝试暴力关闭");
}
} catch (InterruptedException ex) {
System.out.println("异常了");
Thread.currentThread().interrupt();
}
}
}
}
- 2.在启动类中加入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;
}
}
这样咱们就配置好了，咱们再来测试一遍，test的接口仍是休眠10秒
咱们发现此次没有报错了，他是等待了一段时间以后再结束的线程池，这个时间就是咱们在ElegantShutdownConfig类中配置的waitTime。
那可能你会有疑问了，jvm没有当即中止，那这个时候在有请求会发生什么呢？若是关闭的时候有新的请求，服务将不在接收此请求。
数据备份操做
若是我想在服务中止的时候作点备份操做啥的，应该怎么作呢？其实很简单在你要执行的方法上添加一个注解便可：@PreDestroy
Destroy：消灭、毁灭 pre:前缀缩写
因此合在一块儿的意思就是在容器中止以前执行一次，你能够在这里面作备份操做，也能够作记录停机时间等。
新增服务中止备份工具类：DataBackupConfig.java
package com.ymy.config;
import org.springframework.context.annotation.Configuration;
import javax.annotation.PreDestroy;
@Configuration
public class DataBackupConfig {
@PreDestroy
public void backData(){
System.out.println("正在备份数据。。。。。。。。。。。");
}
}
咱们再来测试而后打印控制台日志：
来源：https://blog.csdn.net/qq_3322...
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