线程阻塞

　　研究ThreadPoolExecutor.excute()源码会发现，它调用了BlockingQueue.offer()来实现多余任务的入队。BlockingQueue有两个方法：BlockingQueue.offer()和BlockingQueue.put()，前者在队列满时不阻塞，直接失败，后者在队列满时阻塞。那么，问题就很简单了，继承某个BlockingQueue，然后将offer()重写，改成调用put()就搞定了！最短的代码量，也能起到很好的效果哦！

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

public class ExecutorsEx extends Thread{

    /**
     * 创建一个堵塞队列
     *
     * @param threadSize
     * @return
     */
    public static ExecutorService newFixedThreadPool(int threadSize) {
        return new ThreadPoolExecutor(threadSize, threadSize, 0L, TimeUnit.MILLISECONDS,
                new LinkedBlockingQueue<Runnable>(1) {

                    private static final long serialVersionUID = -9028058603126367678L;

                    @Override
                    public boolean offer(Runnable e) {
                        try {
                            put(e);
                            return true;
                        } catch (InterruptedException ie) {
                            Thread.currentThread().interrupt();
                        }
                        return false;
                    }
                });
    }
    public static void main(String[] args) {
        ExecutorService service = ExecutorsEx.newFixedThreadPool(2);
        service.execute(new myThread());
        service.execute(new myThread());
        service.execute(new myThread());
        service.execute(new myThread());
        service.execute(new myThread());
        service.shutdown();
    }
}
class myThread extends Thread{

    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName()+"正在运行。。。。。。");
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}