Java手写线程池的实现方法

import java.util.List;/** * 线程接口 * * @Author yjian * @Date 14:49 2017/10/14 **/public interface IThreadPool { //加入任务 void execute(Runnable task); //加入任务 void execute(Runnable[] tasks); //加入任务 void execute(List<Runnable> tasks); //销毁线程 void destroy();}

import java.util.LinkedList;import java.util.List;import java.util.concurrent.atomic.AtomicLong;/** * 线程实现类（简易实现，自行优化.提供思路） * * @Author yjian * @Date 14:49 2017/10/14 **/@SuppressWarnings("ALL")public class ThreadPoolImpl implements IThreadPool { //默认开启线程个数 static int WORKER_NUMBER = 5; //完成任务线程数 可见性 static volatile int sumCount = 0; //任务队列 list非线程安全，可以优化为BlockingQueue static List<Runnable> taskQueue = new LinkedList<Runnable>(); //线程工作组 WorkerThread[] workThreads; //原子性 static AtomicLong threadNum = new AtomicLong(); static ThreadPoolImpl threadPool; //构造方法 public ThreadPoolImpl() {  this(WORKER_NUMBER); } public ThreadPoolImpl(int workerNum) {  this.WORKER_NUMBER = workerNum;  //开辟工作线程空间  workThreads = new WorkerThread[WORKER_NUMBER];  //开始创建工作线程  for (int i = 0; i < WORKER_NUMBER; i++) {   workThreads[i] = new WorkerThread();   Thread thread = new Thread(workThreads[i], "ThreadPool-worker" + threadNum.incrementAndGet());   System.out.println("初始化线程数" + (i + 1) + "---------当前线程名称:" + thread.getName());   thread.start();  } } @Override public String toString() {  return "工作线程数量为" + WORKER_NUMBER    + "已完成的任务数" + sumCount +    "等待任务数量" + taskQueue.size(); } //获取线程池 public static IThreadPool getThreadPool() {  return getThreadPool(WORKER_NUMBER); } public static IThreadPool getThreadPool(int workerNum) {  //容错性，如果小于等于0就默认线程数  if (workerNum <= 0) {   workerNum = WORKER_NUMBER;  }  if (threadPool == null) {   threadPool = new ThreadPoolImpl(workerNum);  }  return threadPool; } @Override public void execute(Runnable task) {  synchronized (taskQueue) {   taskQueue.add(task);   taskQueue.notifyAll();  } } @Override public void execute(Runnable[] tasks) {  synchronized (taskQueue) {   for (Runnable task : tasks) {    taskQueue.add(task);   }   taskQueue.notifyAll();  } } @Override public void execute(List<Runnable> tasks) {  synchronized (taskQueue) {   for (Runnable task : tasks) {    taskQueue.add(task);   }   taskQueue.notifyAll();  } } @Override public void destroy() {  //循环是否还存在任务，如果存在等待20毫秒处理时间  while (!taskQueue.isEmpty()) {   try {    Thread.sleep(20);   } catch (InterruptedException e) {    e.printStackTrace();   }  }  //如果任务队列已处理完成，销毁线程，清空任务  for (int i = 0; i < WORKER_NUMBER; i++) {   workThreads[i].setWorkerFlag();   workThreads[i] = null;  }  threadPool = null;  taskQueue.clear(); } //创建工作线程池 class WorkerThread extends Thread {  //用来标识当前线程属于活动可用状态  private boolean isRunning = true;  @Override  public void run() {   Runnable runnable = null;   //死循环   while (isRunning) {    //非线程安全，所以采用同步锁    synchronized (taskQueue) {     while (isRunning && taskQueue.isEmpty()) {      try {       //如果任务队列为空，等待20毫秒 监听任务到达       taskQueue.wait(20);      } catch (Exception e) {       e.printStackTrace();      }     }     //任务队列不为空     if (!taskQueue.isEmpty()) {      runnable = taskQueue.remove(0);//获取第一个任务     }    }    if (runnable != null) {     runnable.run();    }    sumCount++;    runnable = null;   }  }  //销毁线程  public void setWorkerFlag() {   isRunning = false;  } }}

import java.util.ArrayList;import java.util.List;/** * 测试类 * * @Author yjian * @Date 15:37 2017/10/14 **/public class ThreadPoolTest { public static void main(String[] args) {  //获取线程池  IThreadPool t = ThreadPoolImpl.getThreadPool(20);  List<Runnable> taskList = new ArrayList<Runnable>();  for (int i = 0; i < 100; i++) {   taskList.add(new Task());  }  //执行任务  t.execute(taskList);  System.out.println(t);  //销毁线程  t.destroy();  System.out.println(t); } static class Task implements Runnable {  private static volatile int i = 1;  @Override  public void run() {   System.out.println("当前处理的线程:" + Thread.currentThread().getName() + " 执行任务" + (i++) + " 完成");  } }}