前言

昨天学习关于定时器的相关知识。今天花时间去模拟实现了一个定时器，同时也去模拟实现了一个线程池(线程数目为定值)。我感觉我收获了很多，对于线程的理解加深了。跟大家分享一下~

 线程池和定时器(这个是主要)的实现

代码 

线程池

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
class MyThreadPool{
    //.创建任务队列
    private BlockingQueue<Runnable> blockingQueue=null;
    //.创建固定线程数目的线程池
    public MyThreadPool(int n) throws InterruptedException {
        //给任务队列给出容量大小
        blockingQueue=new ArrayBlockingQueue<>(1000);
        //创建线程
      for(int i=0;i<n;i++){
          Thread t=new Thread(()->{
              Runnable task= null;
              try {
                  while(true){
                      task = blockingQueue.take();
                      task.run();
                  }

              } catch (InterruptedException e) {
                  throw new RuntimeException(e);
              }


          });
//          t.setDaemon(true);
          t.start();

      }
    }
    //提交任务,将任务放入任务队列
    public void submit(Runnable task) throws InterruptedException {
        blockingQueue.put(task);
    }
}

public class demo40 {
    public static void main(String[] args) throws InterruptedException {
        MyThreadPool myThreadPool=new MyThreadPool(10);
        //往线程池里面提交任务
        for(int i=0;i<100;i++){
            int id=i;
            myThreadPool.submit(()->{
                System.out.println(Thread.currentThread().getName()+" "+id);
            });
        }

    }
}

 定时器

package Maybe;

import java.util.PriorityQueue;

class Mytimertask implements Comparable<Mytimertask>{
    private long time;
    private Runnable task;
    public Mytimertask(Runnable task,long time){
        this.task=task;
        this.time=time;
    }
    public void run(){
        task.run();
    }
    public long gettime(){
        return time;
    }

    @Override
    public int compareTo(Mytimertask o) {
        return (int)(o.time-this.time);
    }
}
class Mytimer{
    Object locker=new Object();
    PriorityQueue<Mytimertask> queue=new PriorityQueue<>();
    public void schedule(Runnable task,long delay){
        synchronized(locker){
            Mytimertask task1=new Mytimertask(task,System.currentTimeMillis()+delay);
            queue.offer(task1);
            locker.notifyAll();
        }
    }
    public Mytimer(){
        Thread t=new Thread(()->{
            synchronized(locker){
                while(true){
                    while(queue.isEmpty()){
                        try {
                            locker.wait();
                        } catch (InterruptedException e) {
                            throw new RuntimeException(e);
                        }
                    }
                    Mytimertask task=queue.peek();
                    if(task.gettime()>System.currentTimeMillis()){
                        try {
                            locker.wait(task.gettime()-System.currentTimeMillis());
                        } catch (InterruptedException e) {
                            throw new RuntimeException(e);
                        }
                    }else{
                        task.run();
                        queue.poll();
                    }
                }
            }

        });
        t.start();
    }
}



public class may {
    public static void main(String[] args) {
        Mytimer mytimer=new Mytimer();
        mytimer.schedule(new Runnable() {
            @Override
            public void run() {
                System.out.println("hello 3000");
            }
        },3000);
        mytimer.schedule(new Runnable() {
            @Override
            public void run() {
                System.out.println("hello 2000");
            }
        },2000);

    }
}

结语 

本次的分享就到此为止了~ 最近要期末了，自学的东西要慢下来了，等期末过后，再猛猛地学。

希望期末周能快点过~~