Java8 线程池

1，完成多任务的线程自动负载均衡
2，完成多线程结果归并

ExecutorService executorService = Executors.newFixedThreadPool(5);
List<Future<Integer>> list = new ArrayList<>();

for (int i = 0; i < 10; i++) {
  Future<Integer> future = executorService.submit(new Callable<Integer>() {
    public Integer call() throws Exception {
      int sum = 0;
      for (int i = 1; i <= 100; i++) {
        sum += i;
      }
      System.out.println("111");
      return sum;
    }
  });
  list.add(future);
}

for (Future<Integer> integerFuture : list) {
  Integer s = integerFuture.get();
  System.out.println(s);
}
executorService.shutdown();

输出10次 5050，不执行integerFuture.get();也会打印 111，表明call是被执行的。