线程池以及四种常见线程池

线程池以及四种常见线程池

public ThreadPoolExecutor(int corePoolSize,//核心线程池大小，核心线程将会尽可能地一直活着
                          int maximumPoolSize,//线程池最大数量包括核心线程数量
                          long keepAliveTime,//非核心线程最长存活时间
                          TimeUnit unit,//keepAliveTime的单位
                          BlockingQueue<Runnable> workQueue,//等待线程的队列
                          ThreadFactory threadFactory,//线程工程
                          RejectedExecutionHandler handler)//线程拒绝执行回调

四种常见的线程池：

• Executors.newCachedThreadPool()

  new ThreadPoolExecutor(0, Integer.MAX_VALUE,
                                    60L, TimeUnit.SECONDS,
                                    new SynchronousQueue<Runnable>())
  

• Executors.newFixedThreadPool(int nThreads)

  new ThreadPoolExecutor(nThreads, nThreads,
                                    0L, TimeUnit.MILLISECONDS,
                                    new LinkedBlockingQueue<Runnable>())
  

• Executors.newScheduledThreadPool(int nCorepoolSize)

  public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) {
      return new ScheduledThreadPoolExecutor(corePoolSize);
  }
  
  //ScheduledThreadPoolExecutor():
  public ScheduledThreadPoolExecutor(int corePoolSize) {
      super(corePoolSize, Integer.MAX_VALUE,
            DEFAULT_KEEPALIVE_MILLIS, MILLISECONDS,
            new DelayedWorkQueue());
  }
  

  ​

• Executors.newSingleThreadPool()

  public static ExecutorService newSingleThreadExecutor() {
      return new FinalizableDelegatedExecutorService
          (new ThreadPoolExecutor(1, 1,
                                  0L, TimeUnit.MILLISECONDS,
                                  new LinkedBlockingQueue<Runnable>()));
  }
  

  ​