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1、SingleThreadExecutor 单线程的线程池

public static ScheduledExecutorService newSingleThreadScheduledExecutor() {        return new DelegatedScheduledExecutorService            (new ScheduledThreadPoolExecutor(1));    }

2、FixedThreadPool固定大小线程池

public static ExecutorService newFixedThreadPool(int nThreads) {        return new ThreadPoolExecutor(nThreads, nThreads,                                      0L, TimeUnit.MILLISECONDS,                                      new LinkedBlockingQueue
   
    ());    }
   

3、ScheduledThreadPool 延迟执行或固定周期执行的线程池

public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) {        return new ScheduledThreadPoolExecutor(corePoolSize);    }    public ScheduledThreadPoolExecutor(int corePoolSize) {        super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS,              new DelayedWorkQueue());    }    public ThreadPoolExecutor(int corePoolSize,                              int maximumPoolSize,                              long keepAliveTime,                              TimeUnit unit,                              BlockingQueue
   
     workQueue) {        this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,             Executors.defaultThreadFactory(), defaultHandler);    }
   

4、CachedThreadPool 可变大小的线程池

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

上述前四个线程池类型基本都依赖下面的基础函数

/**     * Creates a new {@code ThreadPoolExecutor} with the given initial     * parameters and default thread factory and rejected execution handler.     * It may be more convenient to use one of the {@link Executors} factory     * methods instead of this general purpose constructor.     *     * @param corePoolSize 线程池中的核心线程数     * @param maximumPoolSize 池中最大线程数     * @param keepAliveTime 当线程数超过核心线程数时，这个代表空线程在被终止前最长生存时间     * @param unit 最长存活时间的单位     * @param workQueue 线程池的工作队列，这个队列仅保存被Runnable任务execute方法提交的任务     * @throws IllegalArgumentException 如果下面条件出现会抛出IllegalArgumentException 异常：     *         {@code corePoolSize < 0}
     *         {@code keepAliveTime < 0}
     *         {@code maximumPoolSize <= 0}
     *         {@code maximumPoolSize < corePoolSize}     * @throws NullPointerException if {@code workQueue} is null     */    public ThreadPoolExecutor(int corePoolSize,                              int maximumPoolSize,                              long keepAliveTime,                              TimeUnit unit,                              BlockingQueue
   
     workQueue) {        this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,             Executors.defaultThreadFactory(), defaultHandler);    }
   

只是第一、三个的工作队列有所不同是DelayedWorkQueue，如下所示：

public ScheduledThreadPoolExecutor(int corePoolSize) {        super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS,              new DelayedWorkQueue());    }

5、WorkStealingPool 采用工作窃取算法队列的线程池

该线程池与前四个不同，适合处理比较耗时的工作任务

/**     * Creates a work-stealing thread pool using all     * {@link Runtime#availableProcessors available processors}     * as its target parallelism level.     * @return the newly created thread pool     * @see #newWorkStealingPool(int)     * @since 1.8     */  public static ExecutorService newWorkStealingPool() {        return new ForkJoinPool            (Runtime.getRuntime().availableProcessors(),             ForkJoinPool.defaultForkJoinWorkerThreadFactory,             null, true);    }

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