Spring Boot 在关闭时,如果有请求没有响应完,在不同的容器会出现不同的结果,例如,在 Tomcat 和 Undertow 中会出现中断异常,那么就有可能对业务造成影响。所以,优雅停机非常有必要性,目前官方是没有提供很好的策略来实现。

Each SpringApplication registers a shutdown hook with the JVM to ensure that the ApplicationContext closes gracefully on exit. All the standard Spring lifecycle callbacks (such as the DisposableBean interface or the @PreDestroy

Spring Boot Application 在接收到停机信号后,可以通过 ​​DisposableBean​​ 接口 、 ​​@PreDestroy​​ 注解 或者 ​​ContextClosedEvent​

版本信息

Spring Boot 版本: 2.0.0.RELEASE

Tomcat 优雅停机

@SpringBootApplication
public class Application{

public static void main(String[] args){
SpringApplication.run(Application.class, args);
}

/**
* 用于接受 shutdown 事件
*/
@Bean
public GracefulShutdown gracefulShutdown(){
return new GracefulShutdown();
}

@Bean
public ServletWebServerFactory servletContainer(){
TomcatServletWebServerFactory tomcat = new TomcatServletWebServerFactory();
tomcat.addConnectorCustomizers(gracefulShutdown());
return tomcat;
}

/**
* 优雅关闭 Spring Boot
*/
private class GracefulShutdown implements TomcatConnectorCustomizer, ApplicationListener<ContextClosedEvent> {
private final Logger log = LoggerFactory.getLogger(GracefulShutdown.class);
private volatile Connector connector;
private final int waitTime = 30;
@Override
public void customize(Connector connector){
this.connector = connector;
}
@Override
public void onApplicationEvent(ContextClosedEvent contextClosedEvent){
this.connector.pause();
Executor executor = this.connector.getProtocolHandler().getExecutor();
if (executor instanceof ThreadPoolExecutor) {
try {
ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
threadPoolExecutor.shutdown();
if (!threadPoolExecutor.awaitTermination(waitTime, TimeUnit.SECONDS)) {
log.warn("Tomcat thread pool did not shut down gracefully within " + waitTime + " seconds. Proceeding with forceful shutdown");
}
} catch

Undertow 优雅停机

@SpringBootApplication
public class Application{

public static void main(String[] args){
SpringApplication.run(Application.class, args);
}

/**
* 优雅关闭 Spring Boot
*/
@Component
public class GracefulShutdown implements ApplicationListener<ContextClosedEvent> {

@Autowired
private GracefulShutdownWrapper gracefulShutdownWrapper;

@Autowired
private ServletWebServerApplicationContext context;

@Override
public void onApplicationEvent(ContextClosedEvent contextClosedEvent){
gracefulShutdownWrapper.getGracefulShutdownHandler().shutdown();
try {
UndertowServletWebServer webServer = (UndertowServletWebServer)context.getWebServer();
Field field = webServer.getClass().getDeclaredField("undertow");
field.setAccessible(true);
Undertow undertow = (Undertow) field.get(webServer);
List<Undertow.ListenerInfo> listenerInfo = undertow.getListenerInfo();
Undertow.ListenerInfo listener = listenerInfo.get(0);
ConnectorStatistics connectorStatistics = listener.getConnectorStatistics();
while (connectorStatistics.getActiveConnections() > 0){}
}catch (Exception e){
// Application Shutdown
@Component
public class GracefulShutdownWrapper implements HandlerWrapper{

private GracefulShutdownHandler gracefulShutdownHandler;

@Override
public HttpHandler wrap(HttpHandler handler){
if(gracefulShutdownHandler == null) {
this.gracefulShutdownHandler = new GracefulShutdownHandler(handler);
}
return gracefulShutdownHandler;
}

public GracefulShutdownHandler getGracefulShutdownHandler(){
return
@Component
@AllArgsConstructor
public class UndertowExtraConfiguration{

private final GracefulShutdownWrapper gracefulShutdownWrapper;

@Bean
public UndertowServletWebServerFactory servletWebServerFactory(){
UndertowServletWebServerFactory factory = new UndertowServletWebServerFactory();
factory.addDeploymentInfoCustomizers(deploymentInfo -> deploymentInfo.addOuterHandlerChainWrapper(gracefulShutdownWrapper));
factory.addBuilderCustomizers(builder -> builder.setServerOption(UndertowOptions.ENABLE_STATISTICS, true));
return

Jetty 优雅停机

默认支持所有请求完毕后再关闭,缺点:客户端接收不到响应,有待改进!