//结点类
public class Node {Object element; //数据域Node next;  //指针域//头结点的构造方法public Node(Node nextval){this.next = nextval;}//非头结点的构造方法public Node(Object obj,Node nextval){this.element = obj;this.next = nextval;}//获得当前结点的后继结点public Node getNext(){return this.next;}//获得当前的数据域的值public Object getElement(){return this.element;}//设置当前结点的指针域public void setNext(Node nextval){this.next = nextval;}//设置当前结点的数据域public void setElement(Object obj){this.element = obj;}public String toString(){return this.element.toString();  }
}

//栈接口
public interface Stack {//入栈public void push(Object obj) throws Exception;//出栈public Object pop() throws Exception;//获得栈顶元素public Object getTop() throws Exception;//判断栈是否为空public boolean isEmpty();
}//顺序栈
public class SequenceStack implements Stack {Object[] stack; //对象数组final int defaultSize =10; //默认最大长度int top; //栈顶位置int maxSize; //最大长度public SequenceStack(){init(defaultSize);  }public SequenceStack(int size){init(size);}public void init(int size){this.maxSize = size;top =0;stack = new Object[size];}@Overridepublic Object getTop() throws Exception {// TODO Auto-generated method stubif(isEmpty()){throw new Exception("堆栈为空！");}return stack[top-1];}@Overridepublic boolean isEmpty() {// TODO Auto-generated method stubreturn top==0;}@Overridepublic Object pop() throws Exception {// TODO Auto-generated method stubif(isEmpty()){throw new Exception("堆栈为空！");}top--;return stack[top];}@Overridepublic void push(Object obj) throws Exception {// TODO Auto-generated method stub//首先判断栈是否已满if(top == maxSize){throw new Exception("堆栈已满！");}stack[top]=obj;top++;}}
//链表堆栈
public class LinkStack implements Stack {Node head;  //栈顶指针int size;  //结点的个数public LinkStack(){head = null;size = 0;}@Overridepublic Object getTop() throws Exception {// TODO Auto-generated method stubreturn head.getElement();}@Overridepublic boolean isEmpty() {// TODO Auto-generated method stubreturn head==null;}@Overridepublic Object pop() throws Exception {// TODO Auto-generated method stubif(isEmpty()){throw new Exception("栈为空！");}Object obj = head.getElement();head = head.getNext();size--;return obj;}@Overridepublic void push(Object obj) throws Exception {// TODO Auto-generated method stubhead = new Node(obj,head);size++;}}

以上是节点，顺序栈和链表栈；

下面分别是表达式括号的匹配使用和表达式计算；

public class Test {public static String[] expToStringArray(String exp){int n = exp.length();String[] arr = new String[n];for(int i=0;i<arr.length;i++){arr[i]= exp.substring(i, i+1);}return arr;}//判断表达式的括号是否正确public static void signCheck(String exp)throws Exception{SequenceStack stack = new SequenceStack();String[] arr = Test.expToStringArray(exp);for(int i=0;i<arr.length;i++){if(arr[i].equals("(")||arr[i].equals("[")||arr[i].equals("{")){stack.push(arr[i]);}else if(arr[i].equals(")")&& !stack.isEmpty()&& stack.getTop().equals("(")){stack.pop();}else if(arr[i].equals(")")&& !stack.isEmpty()&& !stack.getTop().equals("(")){System.out.println("左右括号匹配次序不正确！");return ;}else if(arr[i].equals("]")&& !stack.isEmpty()&& stack.getTop().equals("[")){stack.pop();}else if(arr[i].equals("]")&& !stack.isEmpty()&& !stack.getTop().equals("[")){System.out.println("左右括号匹配次序不正确！");return ;}else if(arr[i].equals("}")&& !stack.isEmpty()&& stack.getTop().equals("{")){stack.pop();}else if(arr[i].equals("}")&& !stack.isEmpty()&& !stack.getTop().equals("{")){System.out.println("左右括号匹配次序不正确！");return ;}else if(arr[i].equals(")")||arr[i].equals("]")||arr[i].equals("}")&& stack.isEmpty()){System.out.println("右括号多于左括号！");return ;}}if(!stack.isEmpty()){System.out.println("左括号多于右括号！");}else{System.out.println("括号匹配正确！");}}//计算后缀表达式，表达式一个一个根据规则入栈和出栈public static void expCaculate(LinkStack stack) throws Exception{char ch; //扫描每次输入的字符。int x1,x2,b=0; //x1,x2:两个操作数 ，b字符的ASCII码System.out.println("输入后缀表达式并以#符号结束:");while((ch =(char)(b=System.in.read()))!='#'){//如果是数字，说明是操作数则压入堆栈if(Character.isDigit(ch)){stack.push(new Integer(Character.toString(ch)));}//如果不是数字，说明是运算符else{x2 = ((Integer)stack.pop()).intValue();x1 = ((Integer)stack.pop()).intValue();switch(ch){case '+':x1+=x2;break;case '-':x1-=x2;break;case '*':x1*=x2;break;case '/':if(x2==0){throw new Exception("分母不能为零！");}else{x1/=x2;}break;}stack.push(new Integer(x1));}}System.out.println("后缀表达式计算结果是："+stack.getTop());}/*** @param args*/public static void main(String[] args) throws Exception {// TODO Auto-generated method stub//SequenceStack stack = new SequenceStack(10);/*LinkStack stack = new LinkStack();Scanner in = new Scanner(System.in);int temp;for(int i=0;i<10;i++){System.out.println("请输入第"+(i+1)+"个整数：");temp = in.nextInt();stack.push(temp);}while(!stack.isEmpty()){System.out.println(stack.pop());}*///String str = "([(a+b)-(c*e)]+{a+b}";//Test.signCheck(str);//(2+3)*(3-1)/2=5   23+31-*2/LinkStack stack = new LinkStack();Test.expCaculate(stack);}}