問題描述：計算一批正整數(shù)中質(zhì)數(shù)的個數(shù)
使用方法：
使用CompletableFuture結(jié)合線程池 多線程統(tǒng)計質(zhì)數(shù)的個數(shù)，最后匯總各個線程的數(shù)量。代碼如下：

// 創(chuàng)建一個固定大小的線程池
ExecutorService executorService = Executors.newFixedThreadPool(10);

CompletableFuture<Integer> future1 = CompletableFuture.supplyAsync(() -> {
  int count = getPrimeNumberCount(2, 100000);
  System.out.println(Thread.currentThread().getName() + ", count = " + count);
  return count;
}, executorService);
CompletableFuture<Integer> future2 = CompletableFuture.supplyAsync(() -> {
  int count = getPrimeNumberCount(100000, 200000);
  System.out.println(Thread.currentThread().getName() + ", count = " + count);
  return count;
}, executorService);

System.out.println(future1.join() + future2.join());