线程池

package com.zh;

import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ThreadPoolTest implements Runnable {
    @Override
    public void run() {
        try {
            Thread.sleep(300);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {

        LinkedBlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>(5);
        RejectedExecutionHandler handler = new ThreadPoolExecutor.DiscardPolicy();
        // ThreadPoolExecutor threadPool = new ThreadPoolExecutor(5, 10, 60,
        // TimeUnit.SECONDS, queue,handler);
        ThreadPoolExecutor threadPool = new ThreadPoolExecutor(5, 10, 60, TimeUnit.SECONDS, queue); // 默认直接抛出异常
        for (int i = 0; i < 16; i++) {
            threadPool.execute(new Thread(new ThreadPoolTest(), "Thread".concat(i + "")));
            System.out.println("线程池中活跃的线程数： " + threadPool.getPoolSize());
            if (queue.size() > 0) {
                System.out.println("----------------队列中阻塞的线程数" + queue.size());
            }
        }
        threadPool.shutdown();
    }
}

 

运行过程

 刚开始都是在创建新的线程，达到核心线程数量5个后，新的任务进来后不再创建新的线程，而是将任务加入工作队列，任务队列到达上线5个后，新的任务又会创建新的线程，直到达到线程池最大的线程数量10个，后面的任务则根据配置的饱和策略来处理。我们这里没有具体配置，使用的是默认的配置AbortPolicy:直接抛出异常。