如何在Java 7中使用執行緒池來實現任務的平行計算與合併

import java.util.concurrent.*;

public class ThreadPoolExample {

    private static final int THREAD_POOL_SIZE = 4;

    public static void main(String[] args) {
        // 创建线程池
        ExecutorService executor = Executors.newFixedThreadPool(THREAD_POOL_SIZE);
        
        // 创建一个Callable任务
        Callable<Integer> callableTask = () -> {
            int sum = 0;
            for (int i = 0; i < 100; i++) {
                sum += i * i;
                Thread.sleep(10); // 模拟计算过程
            }
            return sum;
        };
        
        // 提交任务到线程池
        Future<Integer> future1 = executor.submit(callableTask);
        Future<Integer> future2 = executor.submit(callableTask);
        Future<Integer> future3 = executor.submit(callableTask);
        Future<Integer> future4 = executor.submit(callableTask);
        
        // 等待任务执行完成并获取结果
        try {
            int sum = future1.get() + future2.get() + future3.get() + future4.get();
            System.out.println("计算结果：" + sum);
        } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
        }
        
        // 关闭线程池
        executor.shutdown();
    }
}