单向队列：一端操作
1.一般：FIFO
2.优先队列和堆栈：LIFO
插入：offer(e)
移除：poll()
获取：peek()

双向队列：两端操作
插入：offerFirst(e) offerLast(e)
移除：pollFirst() pollLast()
获取：peekFirst() peekLast()

ArrayDeque测试

public class QueueTest {

    public static void main(String[] args) {
        Queue<Request> que=new ArrayDeque<Request>();
        //模拟排队情况
        for(int i=0;i<10;i++){
            final int num=i;
            que.offer(new Request() {
                @Override
                public void deposite() {
                    System.out.println("第"+num+"个人办理存款业务，存款额度为："+Math.random()*10000);
                }
            });
        }
        dealWith(que);
    }

    public static void dealWith(Queue<Request> que){
        Request req=null;
        while (null!=(req=que.poll())){
            req.deposite();
        }
    }

}

interface Request{
    //存款
    void deposite();
}

自己实现堆栈

public class StackTest<E> {
    //容器
    private Deque<E> container=new ArrayDeque<E>();
    //容量
    private int cap;

    public StackTest(int cap) {
        this.cap = cap;
    }

    //压栈
    public boolean push(E e){
        if(container.size()>=cap){
            return false;
        }
        return container.offerLast(e);
    }
    //弹栈
    public E pop(){
        return container.pollLast();
    }
    //获取
    public E peek(){
        return container.peekLast();
    }

    public int size(){
        return this.container.size();
    }

    public static void main(String[] args) {
        StackTest<String> backHistory=new StackTest<String>(3);
        backHistory.push("www.baidu.com");
        backHistory.push("www.google.com");
        backHistory.push("www.163.com");
        backHistory.push("www.sina.com");

        System.out.println(backHistory.size());

        String item=null;
        while (null!=(item=backHistory.pop())){
            System.out.println(item);
        }

    }
}```