1.给每个哲学家分配一个编号，同时给每个餐具也分配一个编号。 2.将每个哲学家的就餐过程设计成一个线程。 3.在每个线程中，先尝试获取左边的叉子，再尝试获取右边的刀子。 4.如果获取到了两个餐具，就进行就餐，然后释放两个餐具。 如果没有获取到两个餐具，就释放已经获取到的餐具，等待一段时间后再重复尝试。用java语言为每一步添加代码块

1. 给每个哲学家和餐具分配编号

public class DiningPhilosophers {
    private static final int NUM_PHILOSOPHERS = 5;

    private static final Object[] forks = new Object[NUM_PHILOSOPHERS];
    private static final Philosopher[] philosophers = new Philosopher[NUM_PHILOSOPHERS];

    public static void main(String[] args) {
        for (int i = 0; i < NUM_PHILOSOPHERS; i++) {
            forks[i] = new Object();
        }

        for (int i = 0; i < NUM_PHILOSOPHERS; i++) {
            philosophers[i] = new Philosopher(i, forks[i], forks[(i + 1) % NUM_PHILOSOPHERS]);
            new Thread(philosophers[i]).start();
        }
    }
}

class Philosopher implements Runnable {
    private final int id;
    private final Object leftFork;
    private final Object rightFork;

    public Philosopher(int id, Object leftFork, Object rightFork) {
        this.id = id;
        this.leftFork = leftFork;
        this.rightFork = rightFork;
    }

    @Override
    public void run() {
        while (true) {
            try {
                think();
                eat();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    private void think() throws InterruptedException {
        System.out.println("Philosopher " + id + " is thinking...");
        Thread.sleep((long) (Math.random() * 10000));
    }

    private void eat() throws InterruptedException {
        System.out.println("Philosopher " + id + " is hungry...");
        synchronized (leftFork) {
            System.out.println("Philosopher " + id + " picked up left fork " + (id + 1) % 5);
            synchronized (rightFork) {
                System.out.println("Philosopher " + id + " picked up right fork " + id);
                System.out.println("Philosopher " + id + " is eating...");
                Thread.sleep((long) (Math.random() * 10000));
                System.out.println("Philosopher " + id + " finished eating. Put down right fork " + id + " and left fork " + (id + 1) % 5);
            }
        }
    }
}

2. 将每个哲学家的就餐过程设计成一个线程

for (int i = 0; i < NUM_PHILOSOPHERS; i++) {
    philosophers[i] = new Philosopher(i, forks[i], forks[(i + 1) % NUM_PHILOSOPHERS]);
    new Thread(philosophers[i]).start();
}

3. 在每个线程中，先尝试获取左边的叉子，再尝试获取右边的刀子

synchronized (leftFork) {
    synchronized (rightFork) {
        // eat
    }
}

4. 如果获取到了两个餐具，就进行就餐，然后释放两个餐具。如果没有获取到两个餐具，就释放已经获取到的餐具，等待一段时间后再重复尝试。

private void eat() throws InterruptedException {
    System.out.println("Philosopher " + id + " is hungry...");
    while (true) {
        if (tryPickUpForks()) {
            System.out.println("Philosopher " + id + " is eating...");
            Thread.sleep((long) (Math.random() * 10000));
            putDownForks();
            System.out.println("Philosopher " + id + " finished eating. Put down right fork " + id + " and left fork " + (id + 1) % 5);
            break;
        }
    }
}

private boolean tryPickUpForks() throws InterruptedException {
    if (!isLeftForkTaken()) {
        synchronized (leftFork) {
            if (!isRightForkTaken()) {
                synchronized (rightFork) {
                    return true;
                }
            }
        }
    }
    Thread.sleep((long) (Math.random() * 1000));
    return false;
}

private void putDownForks() {
    synchronized (leftFork) {
        synchronized (rightFork) {
            // do nothing
        }
    }
}

private boolean isLeftForkTaken() {
    synchronized (leftFork) {
        return Thread.holdsLock(leftFork);
    }
}

private boolean isRightForkTaken() {
    synchronized (rightFork) {
        return Thread.holdsLock(rightFork);
    }
}