Async线程池通用配置

import lombok.extern.slf4j.Slf4j;
import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.AsyncConfigurer;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;

/**
 *  使用@EnableAsync来开启异步任务支持，定义线程池
 **/
@Slf4j
@Configuration
@EnableAsync
public class AsyncExecutorConfig implements AsyncConfigurer {

    /**
     * 核心线程数（默认线程数）
     */
    private static final int CORE_POOL_SIZE = 5;
    /**
     * 最大线程数
     */
    private static final int MAX_POOL_SIZE = 10;
    /**
     * 允许线程空闲时间（单位：默认为秒）
     */
    private static final int KEEP_ALIVE_TIME = 10;
    /**
     * 缓冲队列大小
     */
    private static final int QUEUE_CAPACITY = 200;
    /**
     * 线程池名前缀
     */
    private static final String THREAD_NAME_PREFIX = "Async-Service-";


    /**
     * 自定义线程池
     *
     * @return
     */
    @Bean
    public ThreadPoolTaskExecutor asyncTaskExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(CORE_POOL_SIZE);
        executor.setMaxPoolSize(MAX_POOL_SIZE);
        executor.setQueueCapacity(KEEP_ALIVE_TIME);
        executor.setKeepAliveSeconds(QUEUE_CAPACITY);
        executor.setThreadNamePrefix(THREAD_NAME_PREFIX);
        /**
         * 当线程池的任务缓存队列已满并且线程池中的线程数目达到maximumPoolSize，如果还有任务到来就会采取任务拒绝策略
         * 通常有以下四种策略：
         * ThreadPoolExecutor.AbortPolicy:丢弃任务并抛出RejectedExecutionException异常。
         * ThreadPoolExecutor.DiscardPolicy：丢弃任务，但是不抛出异常。
         * ThreadPoolExecutor.DiscardOldestPolicy：丢弃队列最前面的任务，然后重新尝试执行任务（重复此过程）
         * ThreadPoolExecutor.CallerRunsPolicy：重试添加当前的任务，自动重复调用 execute() 方法，直到成功
         */
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        executor.initialize();
        return executor;
    }

    /**
     * 指定默认线程池
     */
    @Override
    public Executor getAsyncExecutor() {
        return taskExecutor();
    }

    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        return (ex, method, params) -> log.error("线程池执行任务发横未知错误,执行方法：{}", method.getName(), ex);
    }