Threads 和 Executors

多线程

发布日期: 2023-02-02

更新日期: 2023-08-27

文章字数: 498

阅读时长: 2 分

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Thread

Executor

Threads

Executors

Executors 是 java.util.concurrent; 包中的一个工具类，用来快速的创建线程池对象等。

创建 ExecutorService

// 创建一个核心线程数等于最大线程数的线程池，线程队列是无界的
public static ExecutorService newFixedThreadPool(int nThreads) &#123;
    return new ThreadPoolExecutor(nThreads, nThreads,
                                  0L, TimeUnit.MILLISECONDS,
                                  new LinkedBlockingQueue<Runnable>());
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// 创建一个核心线程数等于最大线程数的线程池，线程队列是无界的，可指定工厂函数对象
public static ExecutorService newFixedThreadPool(int nThreads, ThreadFactory threadFactory) &#123;
    return new ThreadPoolExecutor(nThreads, nThreads,
                                  0L, TimeUnit.MILLISECONDS,
                                  new LinkedBlockingQueue<Runnable>(),
                                  threadFactory);
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并行线程池，不太常见

// 创建并行线程池，可以使用多个队列
public static ExecutorService newWorkStealingPool(int parallelism) &#123;
    return new ForkJoinPool
        (parallelism,
         ForkJoinPool.defaultForkJoinWorkerThreadFactory,
         null, true);
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public static ExecutorService newWorkStealingPool() &#123;
    return new ForkJoinPool
        (Runtime.getRuntime().availableProcessors(),
         ForkJoinPool.defaultForkJoinWorkerThreadFactory,
         null, true);
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// 创建单线程，其中核心线程数和最大线程数都是 1，任务队列是无界的
public static ExecutorService newSingleThreadExecutor() &#123;
    return new FinalizableDelegatedExecutorService
        (new ThreadPoolExecutor(1, 1,
                                0L, TimeUnit.MILLISECONDS,
                                new LinkedBlockingQueue<Runnable>()));
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// 创建单线程，其中核心线程数和最大线程数都是 1，可以自定义指定 工厂函数对象
public static ExecutorService newSingleThreadExecutor(ThreadFactory threadFactory) &#123;
    return new FinalizableDelegatedExecutorService
        (new ThreadPoolExecutor(1, 1,
                                0L, TimeUnit.MILLISECONDS,
                                new LinkedBlockingQueue<Runnable>(),
                                threadFactory));
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// 创建缓存线程池，核心线程为 0，最大线程为 Integer.MAX_VALUE，同步队列，长度为1
public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory) &#123;
    return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
                                  60L, TimeUnit.SECONDS,
                                  new SynchronousQueue<Runnable>(),
                                  threadFactory);
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创建 ScheduledExecutorService

// 创建单线程，即线程池核心线程为 1 
public static ScheduledExecutorService newSingleThreadScheduledExecutor() &#123;
    return new DelegatedScheduledExecutorService
        (new ScheduledThreadPoolExecutor(1));
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// 创建单线程，并可以指定工厂对象
public static ScheduledExecutorService newSingleThreadScheduledExecutor() &#123;
    return new DelegatedScheduledExecutorService
        (new ScheduledThreadPoolExecutor(1));
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// 创建指定核心线程数的任务调度线程池
public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) &#123;
    return new ScheduledThreadPoolExecutor(corePoolSize);
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// 创建指定核心线程数的任务调度线程池，并且可以指定工厂函数
public static ScheduledExecutorService newScheduledThreadPool(
    int corePoolSize, ThreadFactory threadFactory) &#123;
    return new ScheduledThreadPoolExecutor(corePoolSize, threadFactory);
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