优雅关闭线程池

服务异常终止时，服务内部的线程池中的任务是否需要运行完成，如需要，则增加以下代码，等待任务执行完成后（时间可设置）再销毁 

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextClosedEvent;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * 优雅关闭线程池
 */
@Component
public class ThreadPoolExecutorShutdownDefinition implements ApplicationListener {
    private static final Logger logger = LoggerFactory.getLogger(ThreadPoolExecutorShutdownDefinition.class);

    private final List POOLS = Collections.synchronizedList(new ArrayList<>(12));

    /**
     * 线程中的任务在接收到应用关闭信号量后最多等待多久就强制终止，其实就是给剩余任务预留的时间， 到时间后线程池必须销毁
     */
    private final long AWAIT_TERMINATION = 20;

    /**
     * awaitTermination的单位
     */
    private final TimeUnit TIME_UNIT = TimeUnit.SECONDS;


    public void registryExecutor(ExecutorService executor) {
        POOLS.add(executor);
    }

    /**
     * 参考{@link org.springframework.scheduling.concurrent.ExecutorConfigurationSupport#shutdown()}
     *
     * @param event the event to respond to
     */
    @Override
    public void onApplicationEvent(ContextClosedEvent event) {
        logger.info("graceful shutdown thread pool start, current pool nums: {} >>>>>>>>>>>>>>>>", POOLS.size());
        if (CollectionUtils.isEmpty(POOLS)) {
            return;
        }
        for (ExecutorService pool : POOLS) {
            pool.shutdown();
            try {
                if (!pool.awaitTermination(AWAIT_TERMINATION, TIME_UNIT)) {
                    if (logger.isWarnEnabled()) {
                        logger.warn("Timed out while waiting for executor [{}] to terminate", pool);
                    }
                }
            } catch (InterruptedException ex) {
                if (logger.isWarnEnabled()) {
                    logger.warn("Timed out while waiting for executor [{}] to terminate", pool);
                }
                Thread.currentThread().interrupt();
            }
        }
    }
}

使用，注册线程池

 shutdownDefinition.registryExecutor(executor);