线程池最佳线程数量到底要如何配置？

public class MyCallable implements Callable<String> {
@Override
public String call() throws Exception {          System.out.println("MyCallable call");return "success";    }
public static void main(String[] args) {
        ExecutorService threadPool = Executors.newSingleThreadExecutor();try {
            Future future = threadPool.submit(new MyCallable());            System.out.println(future.get());        } catch (Exception e) {           System.out.println(e);        } finally {            threadPool.shutdown();        }
    }
}

public class MyWorker implements Runnable {

@Overridepublic void run() {        System.out.println("MyWorker run");    }
public static void main(String[] args) {        ExecutorService threadPool = Executors.newFixedThreadPool(8);try {            threadPool.execute(new MyWorker());        } catch (Exception e) {            System.out.println(e);        } finally {            threadPool.shutdown();        }
    }}

public class MyTask implements Runnable {
@Overridepublic void run() {        System.out.println("MyTask call");    }
public static void main(String[] args) {
        ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(8);try {            scheduledExecutorService.schedule(new MyRunnable(), 60, TimeUnit.SECONDS);        } finally {            scheduledExecutorService.shutdown();       }    }}

corePoolSize：核心线程数maximumPoolSize：最大线程数keepAliveTime：空闲线程回收时间间隔unit：空闲线程回收时间间隔单位workQueue：提交任务的队列，当线程数量超过核心线程数时，可以将任务提交到任务队列中。比较常用的有：ArrayBlockingQueue; LinkedBlockingQueue; SynchronousQueue;threadFactory：线程工厂，可以自定义线程的一些属性，比如：名称或者守护线程等handler：表示当拒绝处理任务时的策略

ThreadPoolExecutor.AbortPolicy:丢弃任务并抛出RejectedExecutionException异常。ThreadPoolExecutor.DiscardPolicy：也是丢弃任务，但是不抛出异常。ThreadPoolExecutor.DiscardOldestPolicy：丢弃队列最前面的任务，然后重新尝试执行任务（重复此过程）ThreadPoolExecutor.CallerRunsPolicy：由调用线程处理该任务

public class MyThreadPool implements  Runnable {
private static final ExecutorService  executorService = new ThreadPoolExecutor(8,10,30,            TimeUnit.SECONDS,new ArrayBlockingQueue<>(500),new ThreadPoolExecutor.AbortPolicy());
@Overridepublic void run() {        System.out.println("MyThreadPool run");    }
public static void main(String[] args) {int availableProcessors = Runtime.getRuntime().availableProcessors();try {            executorService.execute(new MyThreadPool());        } catch (Exception e) {            System.out.println(e);        } finally {            executorService.shutdown();        }    }}

int availableProcessors = Runtime.getRuntime().availableProcessors();

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