面试题：Java中CompletableFuture如何实现简单的并行任务处理

Question

请使用Java的CompletableFuture编写代码示例，实现两个独立的任务并行执行，然后将它们的执行结果汇总并输出。假设这两个任务分别是计算1到100的整数和，以及计算1到50的整数平方和。

Answer 1

import java.util.concurrent.CompletableFuture;

public class CompletableFutureExample {
    public static void main(String[] args) {
        CompletableFuture<Integer> sumTask = CompletableFuture.supplyAsync(() -> {
            int sum = 0;
            for (int i = 1; i <= 100; i++) {
                sum += i;
            }
            return sum;
        });

        CompletableFuture<Integer> squareSumTask = CompletableFuture.supplyAsync(() -> {
            int squareSum = 0;
            for (int i = 1; i <= 50; i++) {
                squareSum += i * i;
            }
            return squareSum;
        });

        CompletableFuture<Void> combinedFuture = sumTask.thenCombine(squareSumTask, (sum, squareSum) -> {
            System.out.println("1到100的整数和: " + sum);
            System.out.println("1到50的整数平方和: " + squareSum);
            return null;
        });

        combinedFuture.join();
    }
}