目錄
kill -9 pid ？？？
kill可將指定的信息送至程序。預設的信息爲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）。
講的這個複雜，簡單點來說就是用來殺死linux中的進程，啥？你問我啥是進程？請自行百度。
我相信很多人都用過kill -9 pid 這個命令，徹底殺死進程的意思，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
由於kill -9 屬於暴力刪除，所以會給程序帶來比較嚴重的後果，那究竟會帶來什麼後果呢？
舉個栗子：轉賬功能，再給兩個賬戶進行加錢扣錢的時候突然斷電了？這個時候會發生什麼事情？對於InnoDB存儲引擎來說，沒有什麼損失，因爲它支持事務，但是對於MyISAM引擎來說那簡直就是災難，爲什麼？假如給A賬戶扣了錢，現在需要將B賬戶加錢，這個時候停電了，就會造成，A的錢被扣了，但是B沒有拿到這筆錢，這在生產環境是絕對不允許的，kill -9 相當於突然斷電的效果。
當然了，像轉賬這種，肯定不是使用MyISAM引擎，但是如今分佈式火了起來，跨服務轉賬已經是很平常的事情，這種時候如果使用kill -9 去停止服務，那就不是你的事務能保證數據的準確性了，這個時候你可能會想到分佈式事務，這個世界上沒有絕對的安全系統或者架構，分佈式事務也是一樣，他也會存在問題，概率很小，如果一旦發生，損失有可能是無法彌補的，所以一定不能使用kill -9 去停止服務，因爲你不知道他會造成什麼後果。
在MyISAM引擎中表現的更明顯，比如用戶的信息由兩張表維護，管理員修改用戶信息的時候需要修改兩張表，但由於你的kill -9 暴力結束項目，導致只修改成功了一張表，這也會導致數據的不一致性，這是小事，因爲大不了再修改一次，但是金錢、合同這些重要的信息如果由於你的暴力刪除導致錯亂，我覺得可能比刪庫跑路還嚴重，至少刪庫還能恢復，你這個都不知道錯在哪裏。
那我們應該怎麼結束項目呢？
其實java給我們提供了結束項目的功能，比如：tomcat可以使用shutdown.bat/shutdown.sh進行優雅結束。
什麼叫優雅結束？
第一步：停止接收請求和內部線程。
第二步：判斷是否有線程正在執行。
第三步：等待正在執行的線程執行完畢。
第四步：停止容器。
以上四步纔是正常的結束流程，那springboot怎麼正常結束服務呢？下面我介紹幾種正常結束服務的方案，請拿好小本本做好筆記。
優雅結束服務
kill -15 pid
這種方式也會比較優雅的結束進程（項目），使用他的時候需要慎重，爲什麼呢？我們來看個例子
我寫了一個普通的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之後讓讓程序休眠100秒，然後再打印：test — end，在線程休眠中我們使用kill -15 pid來結束這個進程，你們猜 test — end會被打印嗎？
application.yml
server:
port: 9988
啓動項目
sudo mvn spring-boot:run
這是maven啓動springboot項目的方式
看到這個就代表項目啓動成了
找到項目的進程id
sudo ps -ef |grep shutdown
這個就是項目的進程號，接下來我們先測試test接口，讓線程進入休眠狀態，然後再使用kill -15 14086停止項目
sudo curl 127.0.0.1:9988/test
回到項目日誌
我們發現請求已經到達服務，並且線程已經成功進入休眠，現在我們kill -15 14086結束進程
sudo kill -15 14086
回到日誌
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]
居然報錯了，但是test — end是打印出來了，爲什麼會報錯呢？這就和sleep這個方法有關了，在線程休眠期間，當調用線程的interrupt方法的時候會導致sleep拋出異常，這裏很明顯就是kill -15 這個命令會讓程序馬上調用線程的interrupt方法，目的是爲了讓線程停止，雖然讓線程停止，但線程什麼時候停止還是線程自己說的算，這就是爲什麼我們還能看到：test — end的原因。
ConfigurableApplicationContext colse
我們先看怎麼實現
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";
}
/**
* 停機
*/
@PostMapping(value = "shutdown")
public void shutdown(){
ConfigurableApplicationContext cyx = (ConfigurableApplicationContext) context;
cyx.close();
}
}
重點在：cyx.close();，爲什麼他能停止springboot項目呢？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) {
}
}
}
}
程序在啓動的時候向jvm註冊了一個關閉鉤子，我們在執行colse方法的時候會刪除這個關閉鉤子，jvm就會知道這是需要停止服務。
我們看測試結果
很明顯，他也出發了線程的interrupt方法導致線程報錯，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，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雅的停機。
引入依賴
<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
我這裏對actuator的接口重新給定了一個接口，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
我們發現發送停止服務請求之後還給我們返回了提示信息，很人性化，我們看看控制檯
test — end被執行了，不過在停止線程池的時候還是調用了線程的interrupt方法，導致sleep報錯，這三種方式都可以比較優雅的停止springboot服務，如果我項目中存在線程休眠，我希望10秒以後再停止服務可以嗎？肯定是可以的，我們只需要稍微做點修改就可以了。
1.新增停止springboot服務類：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("請嘗試暴力關閉");
}
} catch (InterruptedException ex) {
System.out.println("異常了");
Thread.currentThread().interrupt();
}
}
}
}
2.在啓動類中加入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;
@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;
}
}
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
我們發現這次沒有報錯了，他是等待了一段時間之後再結束的線程池，這個時間就是我們在ElegantShutdownConfig類中配置的waitTime。
那可能你會有疑問了，jvm沒有立即停止，那這個時候在有請求會發生什麼呢？如果關閉的時候有新的請求，服務將不在接收此請求。
數據備份操作
如果我想在服務停止的時候做點備份操作啥的，應該怎麼做呢？其實很簡單在你要執行的方法上添加一個註解即可：@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行一次，你可以在這裏面做備份操作，也可以做記錄停機時間等。
新增服務停止備份工具類：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("正在備份數據。。。。。。。。。。。");
}
}
我們再來測試然後打印控制檯日誌：
