使用链表实现栈

public class LinkedListStack<E> implements Stack<E> {

    private LinkedList<E> list;

    public LinkedListStack(){
        list = new LinkedList<>();
    }

    @Override
    public int getSize(){
        return list.getSize();
    }

    @Override
    public boolean isEmpty(){
        return list.isEmpty();
    }

    @Override
    public void push(E e){
        list.addFirst(e);
    }

    @Override
    public E pop(){
        return list.removeFirst();
    }

    @Override
    public E peek(){
        return list.getFirst();
    }

    @Override
    public String toString(){
        StringBuilder res = new StringBuilder();
        res.append("Stack: top ");
        res.append(list);
        return res.toString();
    }

    public static void main(String[] args) {
        LinkedListStack<Integer> stack = new LinkedListStack<>();

        for(int i = 0; i < 5; i ++){
            stack.push(i);
            System.out.println(stack);
        }

        stack.pop();
        System.out.println(stack);
    }
}

运行结果：

Stack: top 0->null
Stack: top 1->0->null
Stack: top 2->1->0->null
Stack: top 3->2->1->0->null
Stack: top 4->3->2->1->0->null
Stack: top 3->2->1->0->null

数组栈和链表栈的对比

import java.util.Random;

public class Main {
    //测试使用stack运行opCount个push和pop操作所需要的时间，单位：秒
    private static double testStack(Stack<Integer> stack,int opCount){
        long startTime = System.nanoTime();

        Random random = new Random();
        for (int i = 0; i < opCount; i++) {
            stack.push(random.nextInt(Integer.MAX_VALUE));
        }
        for (int i = 0; i < opCount; i++) {
            stack.pop();
        }
        long endTime = System.nanoTime();
        return (endTime - startTime)/1000000000.0;
    }

    public static void main(String[] args) {
        int opCount = 10000000;
        ArrayStack<Integer> arrayStack = new ArrayStack<>();
        double time1 = testStack(arrayStack,opCount);
        System.out.println("ArrayStack,time: " + time1 + " s");
        LinkedListStack<Integer> linkedListStack = new LinkedListStack<>();
        double time2 = testStack(linkedListStack,opCount);
        System.out.println("LinkedListStack,time: " + time2 + " s");

        //其实这个时间比较复杂，因为LinkedListStack中包含更多的new操作
    }
}