实现个简单的线程池

1 可以手动实现一个最简单的线程池，不考虑性能和等待机制等。
public class Worker extends Thread {

    private LkThreadPool pool;
    private Runnable target;
    private boolean isShutDown=false;


    public Worker(Runnable target,LkThreadPool pool){
        this.pool=pool;
        this.target=target;
    }

    public synchronized void setTarget(Runnable newTarget){
        target=newTarget;
        notifyAll();
    }

    public synchronized void run(){
        while (!isShutDown){
            System.out.println(Thread.currentThread()+"   开始执行");
            if(target!=null){
                //执行
                target.run();
            }

            pool.repool(this);
            System.out.println(Thread.currentThread()+"   执行完毕 回收");
            synchronized (this){
                try {
                    wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public synchronized void shutDown(){
        isShutDown=false;

        notifyAll();
    }

}

public class LkThreadPool {

    private LinkedBlockingQueue<Worker> threadList ;

    private boolean isShutDown=false;

    private int threadCount=0;

    public LkThreadPool(int threadSize){
        if(threadSize>0){
            threadList= new LinkedBlockingQueue<Worker>(threadSize);
        }

    }

    //用完的线程返回线程池
    public synchronized void repool(Worker worker){
        try {
            threadList.put(worker);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public synchronized void start(Runnable target){
        if(threadList.size()>0){
           //有空闲线程
           Worker worker=threadList.poll();
           worker.setTarget(target);
        }else{
           Worker worker=new Worker(target,this);
           worker.start();
        }
    }

    public synchronized void shutdown(){
        isShutDown=true;
        for(Worker worker:threadList){
            worker.shutDown();
        }

    }

}