还在使用kill -9 pid结束spring boot项目吗？不妨试试这几种优雅的方式！
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。
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";
}
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
启动项目
sudo mvn spring-boot:run
这是maven启动springboot项目的方式
看到这个就代表项目启动成了
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
回到项目日志
我们发现请求已经到达服务，并且线程已经成功进入休眠，现在我们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]
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。
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;
@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) {
}
}
}
}
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
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。
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-actuator
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";
}
在请求test途中停止服务
我们发现发送停止服务请求之后还给我们返回了提示信息，很人性化，我们看看控制台
test — end被执行了，不过在停止线程池的时候还是调用了线程的interrupt方法，导致sleep报错，这三种方式都可以比较优雅的停止springboot服务，如果我项目中存在线程休眠，我希望10秒以后再停止服务可以吗？肯定是可以的，我们只需要稍微做点修改就可以了。
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;
@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
我们发现这次没有报错了，他是等待了一段时间之后再结束的线程池，这个时间就是我们在ElegantShutdownConfig类中配置的waitTime。
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 {
@PreDestroy
public void backData(){
System.out.println("正在备份数据。。。。。。。。。。。");
}
}
我们再来测试然后打印控制台日志：
作者：卖托儿索的小火柴
