手撕线程池

线程池是一个很重要的知识点，有时候面试官还会让手撕，所以这里就写了一个简单的线程池

参考：https://blog.csdn.net/hongtaolong/article/details/87808009

package com.CSDN;

import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;

public class MyThreadPoool {
    private static final int WORK_NUM=100;
    private static final int THREAD_NUM=5;
    private int worknum;
    private int threadnum;
    private final Set<WorkThread> threadset;
    private final ArrayBlockingQueue<Runnable> workqueue;

    public MyThreadPoool(){
        this(WORK_NUM,THREAD_NUM);
    }

    public MyThreadPoool(int worknum,int threadnum){
        this.worknum=worknum;
        this.threadnum=threadnum;
        threadset=new HashSet<>();
        workqueue=new ArrayBlockingQueue<Runnable>(worknum);
        for (int i = 0; i < threadnum; i++) {
            WorkThread w=new WorkThread("thead"+i);
            w.start();
            workqueue.add(w);
        }
    }

    public void excute(Runnable r){
        try{
            workqueue.add(r);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    public void shutdown(){
        System.out.println("the ThreadPool is ready to shutdown");
        if(threadset==null||threadset.isEmpty()){
            return;
        }
        for(WorkThread w:threadset){
            w.stopthread();
            w=null;
        }
        threadset.clear();
    }

    public class WorkThread extends Thread{
        public WorkThread(String name){
            setName(name);
        }
        public void run(){
            while(!interrupted()){
                try{
                    Runnable runnable=workqueue.take();
                    if(runnable!=null){
                        System.out.println(getName()+"ready execute:"+runnable.toString());
                        runnable.run();
                    }
                    runnable=null;
                }catch (Exception e){
                    interrupt();
                    e.printStackTrace();
                }
            }
        }

        public void stopthread(){
            interrupt();
        }
    }
}