線程池最佳線程數(shù)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：核心線程數(shù)maximumPoolSize：最大線程數(shù)keepAliveTime：空閑線程回收時間間隔unit：空閑線程回收時間間隔單位workQueue：提交任務的隊列，當線程數(shù)量超過核心線程數(shù)時，可以將任務提交到任務隊列中。比較常用的有：ArrayBlockingQueue; LinkedBlockingQueue; SynchronousQueue;threadFactory：線程工廠，可以自定義線程的一些屬性，比如：名稱或者守護線程等handler：表示當拒絕處理任務時的策略

ThreadPoolExecutor.AbortPolicy:丟棄任務并拋出RejectedExecutionException異常。ThreadPoolExecutor.DiscardPolicy：也是丟棄任務，但是不拋出異常。ThreadPoolExecutor.DiscardOldestPolicy：丟棄隊列最前面的任務，然后重新嘗試執(zhí)行任務（重復此過程）ThreadPoolExecutor.CallerRunsPolicy：由調用線程處理該任務

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();

最佳線程數(shù)目 = （（線程等待時間+線程CPU時間）/線程CPU時間 ）* CPU數(shù)目