用Java设计一个多线程程序，求p=1!+2!+3!+4!+5!+6!+7!+8!+9!+10!,用十个线程分别求1！、2！...10！，在主线程中求这十个阶层的和。

以下是Java设计的多线程程序，用于计算p=1!+2!+3!+4!+5!+6!+7!+8!+9!+10!：

public class FactorialThread extends Thread {
    private int num;
    private BigInteger result;

    public FactorialThread(int num) {
        this.num = num;
    }

    public BigInteger getResult() {
        return result;
    }

    @Override
    public void run() {
        result = factorial(num);
    }

    private BigInteger factorial(int n) {
        BigInteger res = BigInteger.ONE;
        for (int i = 2; i <= n; i++) {
            res = res.multiply(BigInteger.valueOf(i));
        }
        return res;
    }
}

public class MainThread {
    public static void main(String[] args) throws InterruptedException {
        FactorialThread[] threads = new FactorialThread[10];
        BigInteger sum = BigInteger.ZERO;

        // 创建10个线程，分别计算1!到10!
        for (int i = 0; i < threads.length; i++) {
            threads[i] = new FactorialThread(i + 1);
            threads[i].start();
        }

        // 等待所有线程执行完毕
        for (FactorialThread thread : threads) {
            thread.join();
            sum = sum.add(thread.getResult());
        }

        System.out.println("1!+2!+3!+...+10! = " + sum);
    }
}