public class ArrayQueueDemo {
    public static void main(String[] args) {
        ArrayQueue queue = new ArrayQueue(3);
        char key =  ' '; // 接收用户输入
        Scanner scanner = new Scanner(System.in);
        boolean loop = true;
        while (loop){
            System.out.println("s(show):显示队列");
            System.out.println("e(exit):退出程序");
            System.out.println("a(add):添加数据到队列");
            System.out.println("g(get):从队列中取出数据");
            System.out.println("h(head):查看队列头的数据");
            key = scanner.next().charAt(0);
            switch (key){
                case 's' :
                    queue.show();
                    break;
                case 'a' :
                    System.out.println("输入一个数：");
                    int value = scanner.nextInt();
                    queue.addQueue(value);
                    break;
                case 'g':
                    try {
                        int res = queue.getQueue();
                        System.out.printf("取出的数是：%d\n",res);
                    }catch (Exception e){

                        System.out.println(e.getMessage());
                    }
                    break;
                case 'h':
                    try {
                        int res = queue.getFront();
                        System.out.printf("队列的头数据是：%d\n",res);
                    }catch (Exception e){
                        System.out.println(e.getMessage());
                    }
                    break;
                case 'e':
                    scanner.close();
                    loop = false;
                    break;
                default:
                    break;
            }
        }
        System.out.println("程序退出");
    }
}

class ArrayQueue {
    private int maxSize;
    private int front;
    private int rear; // 队列尾
    private int[] arr; // 用数组来保存队列

    // 创建一个队列的构造器
    public ArrayQueue(int arrMaxSize) {
        maxSize = arrMaxSize;
        front = -1;
        rear = -1;
        arr = new int[maxSize];
    }

    // 判断队列是否是满的
    public boolean isFull() {
        return rear == maxSize - 1;
    }

    // 判断队列是否为空
    public boolean isEmpty() {
        return rear == maxSize;
    }

    // 添加
    public void addQueue(int n) {
        // 添加前应该先判断是否为满的
        if (isFull()) {
            throw new RuntimeException("队列满，不能加入");
        }
        // 先把尾向后移动
        rear++;
        arr[rear] = n;
    }

    // get取出
    public int getQueue() {
        if (isEmpty()) {
            throw new RuntimeException("队列为空,不能取到数据");
        }
        front++;
        return arr[front];
    }

    // 展示队列的头
    public int getFront() {
        if (isEmpty()) {
            throw new RuntimeException("队列为空,不能取到头部数据");
        }
        return arr[front + 1];
    }

    // 展示所有的队列的数值
    public void show() {
        if (isEmpty()) {
            System.out.println("队列为空，没有数据");
        }
        for (int i = 0; i < arr.length; i++) {
            System.out.printf("arr[%d]=%d\n", i, arr[i]);
        }
    }
}

程序存在缺陷：数组只能使用一次，即插入->删除之后不能再次插入，解决办法：环形队列