0 线程池类图

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一 ForkJoinPool

• 分治线程池

//指定并发数
public static ExecutorService newWorkStealingPool(int parallelism) {
    return new ForkJoinPool
            (parallelism,
                    ForkJoinPool.defaultForkJoinWorkerThreadFactory,
                    null, true);
}
//默认使用cpu核数的并发数
public static ExecutorService newWorkStealingPool() {
    return new ForkJoinPool
            (Runtime.getRuntime().availableProcessors(),
                    ForkJoinPool.defaultForkJoinWorkerThreadFactory,
                    null, true);
}

二 ThreadPoolExecutor

• 固定线程数线程池

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

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

• 单线程线程池。
  FinalizableDelegatedExecutorService委托模式，代理ThreadPoolExecutor的接口。提供finalize()接口实现，调用shutdown()关闭线程池

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

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

• 缓存线程池

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

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

三 调度线程池ScheduledThreadPoolExecutor

• 支持调度接口委托，和普通线程池接口委托
• 单调度线程池

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

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

• 指定线程数量调度线程池

public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) {
    return new ScheduledThreadPoolExecutor(corePoolSize);
}

public static ScheduledExecutorService newScheduledThreadPool(
        int corePoolSize, ThreadFactory threadFactory) {
    return new ScheduledThreadPoolExecutor(corePoolSize, threadFactory);
}