import java.util.concurrent.ThreadPoolExecutor;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Primary;

import org.springframework.beans.factory.annotation.Value;

import org.springframework.context.annotation.Configuration;

import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

/**

 * @author

 * @date 2019/5/21

 */

@Configuration

public class ThreadPoolConfig {

    @Value("thread.pool.core.pool.size:10")

    private int threadPoolCorePoolSize;

    @Value("thread.pool.max.pool.size:50")

    private int threadPoolMaxPoolSize;

    @Value("thread.pool.queue.capacity:50")

    private int threadPoolQueueCapacity;

    @Value("thread.pool.keep.alive.seconds:300")

    private int threadPoolKeepAliveSeconds;

    @Primary

    @Bean

    public ThreadPoolTaskExecutor threadPoolTaskExecutor() {

        ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();

        /** 核心线程数，默认为1 **/

        threadPoolTaskExecutor.setCorePoolSize(threadPoolCorePoolSize);

        /** 最大线程数，默认为Integer.MAX_VALUE **/

        threadPoolTaskExecutor.setMaxPoolSize(threadPoolMaxPoolSize);

        /** 队列最大长度，一般需要设置值: 大于等于notifyScheduledMainExecutor.maxNum；默认为Integer.MAX_VALUE **/

        threadPoolTaskExecutor.setQueueCapacity(threadPoolQueueCapacity);

        /** 线程池维护线程所允许的空闲时间，默认为60s **/

        threadPoolTaskExecutor.setKeepAliveSeconds(threadPoolKeepAliveSeconds);

        /**

         * 线程池对拒绝任务（无线程可用）的处理策略，目前只支持AbortPolicy、CallerRunsPolicy；默认为后者

         *

         * AbortPolicy:直接抛出java.util.concurrent.RejectedExecutionException异常

         * CallerRunsPolicy:主线程直接执行该任务，执行完之后尝试添加下一个任务到线程池中，可以有效降低向线程池内添加任务的速度

         * DiscardOldestPolicy:抛弃旧的任务、暂不支持；会导致被丢弃的任务无法再次被执行

         * DiscardPolicy:抛弃当前任务、暂不支持；会导致被丢弃的任务无法再次被执行

         */

        threadPoolTaskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());

        return threadPoolTaskExecutor;

    }

}