本文目录一览：

1. java如何自定义栈？
2. 用java编写出来：用数组实现一个栈
3. java用链表实现栈

java如何自定义栈？

public class Stack {
    int[] data;
    int maxSize;
    int top;
    public Stack(int maxSize) {
        this.maxSize = maxSize;
        data = new int[maxSize];
        top = -1;
    }
    // 入栈
    public boolean push(int data) {
        // 入栈先判断栈中是否已满
        if (top + 1 == maxSize) {
            System.out.println("栈已满");
            return false;
        }
        this.data[++top] = data;
        return true;
    }
    // 出栈
    public int pop() throws Exception {
        // 出栈先判断栈是否已空
        if (top == -1) {
            throw new Exception("栈已空");
        }
        return this.data[top--];
    }
    public static void main(String[] args) throws Exception {
        Stack stack = new Stack(1000);
        stack.push(1);
        stack.push(2);
        stack.push(3);
        stack.push(4);
        stack.push(5);
        while (stack.top >= 0) {
            System.out.println(stack.pop());
        }
    }
}

用java编写出来：用数组实现一个栈

public class Stack {
    private Object[] stack;
    private int size;
    public Stack() {
        this(10);
    }
    public Stack(int len) {
        stack = new Object[len];
    }
    public int size() {
        return size;
    }
    public int capacity() {
        return stack.length;
    }
    public void ensureCapacity() {
        if (size() == capacity()) {
            Object[] newStack = new Object[size() * 3 / 2 + 1];
            System.arraycopy(stack, 0, newStack, 0, size());
            stack = newStack;
        }
    }
    public void push(Object o) {
        size++;
        ensureCapacity();
        stack[size - 1] = o;
    }
    public boolean isEmpty() {
        return size == 0;
    }
    public Object pop() {
        if (isEmpty()) {
            throw new ArrayIndexOutOfBoundsException("不能为空");
        }
        Object o = stack[--size];
        stack[size] = null;
        return o;
    }
    public static void main(String[] args) {
        Stack stack = new Stack(3);
        String[] data = new String[]{"a", "b", "c"};
        for (int i = 0; i < data.length; i++) {
            stack.push(data[i]);
            System.out.println(data[i] + "");
        }
        System.out.println("***********");
        while (!stack.isEmpty()) {
            System.out.println(stack.pop() + "");
        }
    }
}

你自己对比一下，我是在你的里面修改的。

java用链表实现栈

public Linked(Object element) {
    this.element = element;
    nextNode = null;
}

是啥意思，给值还return？？把这函数删了