RejectedPolicy--DiscardOldestPolicy-优快云博客

本文通过一个Java示例程序展示了如何使用线程池及其拒绝策略。特别关注了当线程池达到饱和时，如何利用DiscardOldestPolicy来处理多余的请求。此策略会尝试取消当前工作队列中最旧的任务，以便将新任务加入队列。

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package com.jerry.concurrency; import java.util.concurrent.ArrayBlockingQueue; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; public class TestRejectedPolicy { public static void main(String[] args) throws InterruptedException { ThreadPoolExecutor pool = new ThreadPoolExecutor(1, 1, 0, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(1));//设置线程池只启动一个线程阻塞队列一个元素 pool.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardOldestPolicy()); //设置策略为挤掉最旧的 for (int i = 0; i < 10; i++) { final int j = i; pool.submit(new Runnable() { public void run() { System.out.println("线程:"+j + Thread.currentThread().getName()+" 开始执行"); try { Thread.sleep(1000L); } catch (Exception e) { e.printStackTrace(); } System.out.println("线程:"+j + Thread.currentThread().getName()+" 执行完毕"); } }); } Thread.sleep(5000L); pool.shutdown(); System.out.println("关闭后线程终止了吗？" + pool.isTerminated()); } }