多线程程序实现的方式3的好处和弊端 * 好处: * 可以有返回值 * 可以抛出异常

* 弊端:
	* 代码比较复杂,所以一般不用
// 创建线程池对象
		ExecutorService pool = Executors.newFixedThreadPool(2);

		// 可以执行Runnable对象或者Callable对象代表的线程
		Future<Integer> f1 = pool.submit(new MyCallable(100));
		Future<Integer> f2 = pool.submit(new MyCallable(200));

		// V get()
		Integer i1 = f1.get();
		Integer i2 = f2.get();

		System.out.println(i1);
		System.out.println(i2);

		// 结束
		pool.shutdown();

		public class MyCallable implements Callable<Integer> {

			private int number;
		
			public MyCallable(int number) {
				this.number = number;
			}
		
			@Override
			public Integer call() throws Exception {
				int sum = 0;
				for (int x = 1; x <= number; x++) {
					sum += x;
				}
				return sum;
			}
		
		}