java.util.concurrent线程池EXecutor

• Executors线程工厂创建特定线程池
  1. newFixedThreadPool()返回固定数量的线程池，线程数不变，任务提交线程池空闲立即执行，没有暂缓在一个任务队列等待
  2. newSingleThreadExecutor()一个线程的线程池空闲则执行,
  3. newCachedThreadPool()根据实际情况调整线程个数的线程池，不限制最大线程数，无任务不创建线程，60s回收

  4. newScheduledThreadPool()返回ScheduledExecutorService，可指定线程数量

     ExecutorService executorService = Executors.newCachedThreadPool();

     public static ExecutorService newCachedThreadPool() { return new ThreadPoolExecutor(0, Integer.MAX_VALUE, 60L, TimeUnit.SECONDS, new SynchronousQueue()); }

      public ThreadPoolExecutor(int corePoolSize,
                        int maximumPoolSize,
                        long keepAliveTime,
                        TimeUnit unit,
                        BlockingQueue<Runnable> workQueue) {  this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,
       Executors.defaultThreadFactory(), defaultHandler);  }
     

     • corePoolSize 核心线程数(初始化线程数)
     • maximumPoolSize 最大线程数
     • keepAliveTime 空闲时间
     • TimeUnit 空闲单位
     • workQueue 队列