内容：在Java中利用Callable进行带返回结果的线程计算，利用Future表示异步计算的结果，分别计算不同范围的Long求和，类似的思想还能够借鉴到需要大量计算的地方。
public class Sums {public static class Sum implements Callable<Long> {private final Long from;private final Long to;public Sum(long from, long to) {this.from = from;this.to = to;}@Overridepublic Long call() throws Exception {long ans = 0;for (long i = from; i <= to; i++)ans += i;return ans;}}public static void main(String[] args) throws InterruptedException, ExecutionException {ExecutorService executor = Executors.newFixedThreadPool(2);List<Future<Long>> ans = executor.invokeAll(Arrays.asList(new Sum(0, 1000), new Sum(10000, 100000), new Sum(1000000, 1000000)));executor.shutdown();long sum = 0;for (Future<Long> i : ans) {long tmp = i.get();System.out.println(tmp);sum += tmp;}System.out.println("sum : " + sum);}}
，与其在那里苦苦挣扎，碍于面子硬撑，倒不如微笑着面对，
