手写个线程池-白红宇

手写一个线程池，练手
import java.util.concurrent.ArrayBlockingQueue;import java.util.concurrent.BlockingQueue;import java.util.concurrent.atomic.AtomicInteger;/** * ... * * @author : liangfen.zhou * Date : 2018/12/18 下午4:48 */public class TestPool {    private int coreSize,            maxSize;    private AtomicInteger running = new AtomicInteger(0);    private BlockingQueue
    
      queue;    public TestPool(int coreSize, int maxSize, BlockingQueue
     
       queue) {        this.coreSize = coreSize;        this.maxSize = maxSize;        this.queue = queue;    }    public void execute(Runnable runnable) {        if (running.get() < coreSize) {            if(!addWorker(runnable)){                reject();            }        } else {            System.out.println("当前队列大小："+queue.size());            //添加任务到队列中            if(!queue.offer(runnable)){                //如果添加失败则继续创建线程                System.out.println("offer 失败,当前线程数："+running.get());                if(!addWorker(runnable)){                    reject();                }            }        }    }    private void reject() {        throw new RuntimeException("超出大小,当前线程数："+running.get()+" 队列大小："+queue.size());    }    private boolean addWorker(Runnable runnable) {        //如果当前线程数大于最大数则创建失败        if (running.get() >= maxSize) {            return false;        }        Worker worker = new Worker(runnable);        worker.start();        return true;    }    private class Worker extends Thread {        private Runnable runnable;        public Worker(Runnable runnable) {            this.runnable = runnable;            //增加线程运行线程数            System.out.println("创建线程:当前线程数:"+running.incrementAndGet());        }        @Override        public void run() {            try {                while (true) {                    //运行线程                    runnable.run();                    System.out.println("运行结束,当前线程数："+running.get());                    //如果当前运行线程数大于核心大小就退出线程                    if (running.get() > coreSize) {                        break;                    }else{                        //反之从队列里取数据，理论上至少存活coreSize个线程                        try {                            System.out.println("000000：队列大小："+queue.size());                            runnable = queue.take();                            System.out.println("11111111：队列大小："+queue.size());                        } catch (InterruptedException e) {                            e.printStackTrace();                        }                    }                }            } finally {                //线程结束，减少运行数                running.decrementAndGet();                System.out.println("结束线程，当前线程数："+running.get());            }        }    }    public static void main(String[] args) {        Thread.currentThread().setName("main");        TestPool pool = new TestPool(2, 2, new ArrayBlockingQueue<>(3));        for(int i=0;i<100;i++){            final  int j = i;            System.out.println("i="+i+" "+Thread.currentThread().getName());            pool.execute(()->{                try {                    Thread.sleep(100);                    System.out.println("睡0.1秒 完成:"+j);                } catch (InterruptedException e) {                    e.printStackTrace();                }            });        }    }}复制代码