Java异步启动多个CompletableFuture并等待它们完成

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

public class CompletableFutureExample {
    public static void main(String[] args) {
        // 创建多个CompletableFuture对象
        CompletableFuture<String> future1 = CompletableFuture.supplyAsync(() -> task1());
        CompletableFuture<Integer> future2 = CompletableFuture.supplyAsync(() -> task2());
        CompletableFuture<Double> future3 = CompletableFuture.supplyAsync(() -> task3());

        // 等待所有CompletableFuture完成
        CompletableFuture<Void> allFutures = CompletableFuture.allOf(future1, future2, future3);

        // 处理完成的结果
        allFutures.thenRun(() -> {
            try {
                String result1 = future1.get();
                int result2 = future2.get();
                double result3 = future3.get();
                System.out.println("Task 1 result: " + result1);
                System.out.println("Task 2 result: " + result2);
                System.out.println("Task 3 result: " + result3);
            } catch (InterruptedException | ExecutionException e) {
                e.printStackTrace();
            }
        });

        // 等待所有任务完成
        try {
            allFutures.get();
        } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
        }
    }

    private static String task1() {
        // 异步任务1
        return "Task 1 completed";
    }

    private static int task2() {
        // 异步任务2
        return 42;
    }

    private static double task3() {
        // 异步任务3
        return 3.14;
    }
}