两个栈实现队列

import java.util.Stack;public class Solution {    Stack<Integer> stack1 = new Stack<Integer>();    Stack<Integer> stack2 = new Stack<Integer>();        public void push(int node) {        stack1.push(node);    }        public int pop() {          if(stack2.empty()){          while(!stack1.empty())              stack2.push(stack1.pop());          }          return stack2.pop();    }}