Java如何手动创建线程池

ThreadPoolExecutor(int corePoolSize,  int maximumPoolSize,  long keepAliveTime,  TimeUnit unit,  BlockingQueue workQueue)

ThreadPoolExecutor(int corePoolSize,  int maximumPoolSize,  long keepAliveTime,  TimeUnit unit,  BlockingQueue workQueue,  RejectedExecutionHandler handler)

ThreadPoolExecutor(int corePoolSize,  int maximumPoolSize, long keepAliveTime, BlockingQueue workQueue,  ThreadFactory threadFactory)

ThreadPoolExecutor(int corePoolSize,  int maximumPoolSize,  long keepAliveTime,  TimeUnit unit, BlockingQueue workQueue,  RejectedExecutionHandler handler)

public class ThreadPool {     /**      * 线程池的基本大小      */     static int corePoolSize = 10;     /**      * 线程池最大数量      */     static int maximumPoolSizeSize = 100;     /**      * 线程活动保持时间      */     static long keepAliveTime = 1;     /**      * 任务队列      */     static ArrayBlockingQueue workQueue = new ArrayBlockingQueue(10);     public static void main(String[] args) {         ThreadPoolExecutor executor = new ThreadPoolExecutor(                 corePoolSize,                 maximumPoolSizeSize,                 keepAliveTime,                 TimeUnit.SECONDS,                 workQueue,                 new ThreadFactoryBuilder().setNameFormat("XX-task-%d").build());         //提交一个任务         executor.execute(() -> System.out.println("ok"));     } }

public void execute(Runnable command) {         if (command == null)             throw new NullPointerException();         /*          * Proceed in 3 steps:          *          * 1. If fewer than corePoolSize threads are running, try to          * start a new thread with the given command as its first          * task.  The call to addWorker atomically checks runState and          * workerCount, and so prevents false alarms that would add          * threads when it shouldn't, by returning false.          *          * 2. If a task can be successfully queued, then we still need          * to double-check whether we should have added a thread          * (because existing ones died since last checking) or that          * the pool shut down since entry into this method. So we          * recheck state and if necessary roll back the enqueuing if          * stopped, or start a new thread if there are none.          *          * 3. If we cannot queue task, then we try to add a new          * thread.  If it fails, we know we are shut down or saturated          * and so reject the task.          */         int c = ctl.get();         if (workerCountOf(c) 

public class ThreadPoolUtils { public static ThreadPoolExecutor pool=null; // 无响应执行 public static void execute(Runnable runnable){ getThreadPool().execute(runnable); } // 有响应执行 public static Future submit(Callable callable){ return getThreadPool().submit(callable); } // 创造线程池 private static synchronized ThreadPoolExecutor getThreadPool(){ if(pool==null){ // 获取处理器数量 int cpuNum = Runtime.getRuntime().availableProcessors(); // 根据cpu数量,计算出合理的线程并发数 // 最佳线程数目 = （（线程等待时间+线程CPU时间）/线程CPU时间 ）* CPU数目 int maximumPoolSize = cpuNum * 2 + 1; // 七个参数 // 1. 核心线程数 // 2. 最大线程数 // 3. 空闲线程最大存活时间 // 4. 时间单位 // 5. 阻塞队列 // 6. 创建线程工厂 // 7. 拒绝策略 pool=new ThreadPoolExecutor(maximumPoolSize-1, maximumPoolSize, 5, TimeUnit.SECONDS, new ArrayBlockingQueue<>(50), Executors.defaultThreadFactory(), new ThreadPoolExecutor.AbortPolicy()); } return pool; } }