Tomcat优雅关闭

服务的开启和关闭是非常频繁的操作步骤， 所以在默认的情况下， 如果请求没有处理完，这个时候给springboot发起了关闭信号，会导致正在处理的请求失败，所以最好要对于这种情况进行处理。

环境支持：

• Spring Boot 2.x
• Maven 3.x
• Java 8
• Lombok

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.annotation.Bean;
import org.springframework.context.event.ContextClosedEvent;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

@SpringBootApplication
@Slf4j
public class Application {


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


    @Bean
    public GracefulShutdown gracefulShutdown() {
        return new GracefulShutdown();
    }

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

    /**
     * graceful shutdown Spring Boot
     */
    private class GracefulShutdown implements TomcatConnectorCustomizer, ApplicationListener<ContextClosedEvent> {
        private volatile Connector connector;
        private static final int TIMEOUT = 15;

        @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 {
                    log.warn("Tomcat Container ready shutdown");
                    ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
                    threadPoolExecutor.shutdown();
                    if (!threadPoolExecutor.awaitTermination(TIMEOUT, TimeUnit.SECONDS)) {
                        log.warn("Tomcat thread pool did not shut down gracefully within "
                                + TIMEOUT + " seconds. Proceeding with forceful shutdown");
                        threadPoolExecutor.shutdownNow();
                        if (!threadPoolExecutor.awaitTermination(TIMEOUT, TimeUnit.SECONDS)) {
                            log.error("Tomcat thread pool did not terminate");
                        }
                    }
                } catch (InterruptedException ex) {
                    Thread.currentThread().interrupt();
                }
            }
        }
    }
}