理解线程池原理

1、理解什么是线程

      线程是程序运行的最小单位

2、Thread、Runnable、Callable有什么联系

     Thread是线程，Runnable和Callable可以理解为任务，线程的作用是把任务运送到cpu去执行。

public class threadDemo implements Runnable{
    
     @Override
      public void run(){
           //线程工作内容
      }
}

public class threadDemo implements Callable{
    
     @Override
     public String run(){
         //线程内容
         return "hh";
     }
}

3、 实现一个简易线程池

public class FixThreadPool {

    private List<Thread> workers;//线程列表

    private LinkedBlockingQueue<Runnable> blockingQueue;//任务队列

    //线程
    public static class worker extends Thread{

        private FixThreadPool pool;

        public worker(FixThreadPool pool) {
            this.pool = pool;
        }

        @Override
        public void run() {
            while (true) { //反复执行
                Runnable task = null;
                try {
                    //从任务队列中取出任务
                    task = this.pool.blockingQueue.take();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                //执行任务
                if (null != task) {
                    task.run();
                }
            }
        }
    }


    public FixThreadPool(int poolSize, int taskSize) {
        if(poolSize <= 0 || taskSize <= 0){
            throw new IllegalArgumentException("非法参数");
        }
//        this.FixThreadPool = new ArrayList<>(poolSize);
        this.blockingQueue = new LinkedBlockingQueue(taskSize);
        this.workers = Collections.synchronizedList(new ArrayList<>());
        for (int i = 0; i < poolSize; i++) {
            worker worker = new worker(this);
            workers.add(worker);
            worker.start();
        }
    }

    public boolean submit(Runnable task) {
        return this.blockingQueue.offer(task);
    }
}