java实现线程池，实现线程队列(转)

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import java.util.*;
public class ThreadPool
{

   private static ThreadPool theInstance;
   private final int nThreads;//线程池的大小
   private final Workers[] threads;//用数组实现线程池
   private final LinkedList queue;//任务队列

/**
* 单例构造方法
*
* @return
*/
public static ThreadPool getInstance() {
   if (theInstance == null)
    theInstance = new ThreadPool();
   return theInstance;
}

/**
* 私有构造方法默认1个线程在跑
*/
private ThreadPool() {
   //默认1个线程在跑
   this.nThreads = 1;
      queue = new LinkedList();
      threads = new Workers[nThreads];

      for (int i=0; i<nThreads; i++) {
     threads[i] = new Workers();
          threads[i].start();//启动所有工作线程
       }
}

   /**
    * 直接构造线程队列方法
    *
    * @deprecated
    * @param nThreads
    */
public ThreadPool(int nThreads){
     this.nThreads = nThreads;
     queue = new LinkedList();
     threads = new Workers[nThreads];

     for (int i=0; i<nThreads; i++) {
    threads[i] = new Workers();
         threads[i].start();//启动所有工作线程
      }
}

/*
   *
   *执行任务
   */
public void execute(Runnable r) {
    synchronized(queue) {
            queue.addLast(r);
            queue.notify();
    }
}

private class Workers extends Thread {//工作线程类
// logger logger
        public void run() {
               Runnable r;
               while (true) {
                    synchronized(queue) {
                      while (queue.isEmpty()) {//如果任务队列中没有任务，等待
                        try{
                          queue.wait();
                        }catch (InterruptedException ignored){}
                      }
                       r = (Runnable) queue.removeFirst();//有任务时，取出任务
                   }
                   try {
                       r.run();//执行任务
                   }catch (RuntimeException e) {
                      // You might want to log something here
                  }
              }
      }
   }

public static void main(String args[]){
ThreadPool wq=new ThreadPool(1);//10个工作线程
Mytask task[]=new Mytask[20];//20个任务

      for(int i=0;i<20;i++){
        task[i]=new Mytask();
           wq.execute(task[i]);
      }
}
}
class Mytask implements Runnable{//任务接口
         public void run(){
              String name=Thread.currentThread().getName();
              try{
               //System.out.println(System.currentTimeMillis());
                  Thread.sleep(100);//模拟任务执行的时间

              }catch(InterruptedException e){}
              System.out.println(name+" executed OK");
         }
}

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