jsp实现计算器

JavaBean

package com.itheima.domain;

import java.math.BigDecimal;

public class BigDecimalDemo {

	private double firstNum;

	private char fuHao='+';

	private double secondNum;

	public double getFirstNum() {

		return firstNum;

	}

	public void setFirstNum(double firstNum) {

		this.firstNum = firstNum;

	}

	public char getFuHao() {

		return fuHao;

	}

	public void setFuHao(char fuHao) {

		this.fuHao = fuHao;

	}

	public double getSecondNum() {

		return secondNum;

	}

	public void setSecondNum(double secondNum) {

		this.secondNum = secondNum;

	}

	public double toResult(){

		double result = 0;

		switch (fuHao) {

		case '+':

			result=new BigDecimal(firstNum).add(new BigDecimal(secondNum)).doubleValue();

			break;

		case '-':

			result=new BigDecimal(firstNum).subtract(new BigDecimal(secondNum)).doubleValue();

			break;

		case '*':

			result=new BigDecimal(firstNum).multiply(new BigDecimal(secondNum)).doubleValue();

			break;

		case '/':

			if(secondNum!=0){

				result=new BigDecimal(firstNum).divide(new BigDecimal(secondNum)).doubleValue();

			}else{

				throw new RuntimeException();

			}

			break;

		default:

			break;

		}

		return  result;

	}

}

jsp页面

<%@page import="javax.servlet.jsp.tagext.TryCatchFinally"%>

<%@ page language="java" contentType="text/html; charset=utf-8"

    pageEncoding="utf-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

<title>Insert title here</title>

</head>

<body>

<jsp:useBean id="bd" class="com.itheima.domain.BigDecimalDemo"></jsp:useBean>

<jsp:setProperty property="*" name="bd"/>

<%

	double a;

	try{

		a=bd.toResult();

	}catch(Exception e){

		out.println("除法第二个数不能为0");

		a=0;//如果出现异常，则打印出0

	}

%>

<hr/>

您的计算结果是：<jsp:getProperty property="firstNum" name="bd"/>

<jsp:getProperty property="fuHao" name="bd"/>

<jsp:getProperty property="secondNum" name="bd"/>

=<%=a %>

<hr/>

<form action="" method="get">

	<table border='1' width='50%'>

		<tr>

			<td>您输入的第一个数</td>

			<td><input type="text" name="firstNum"></td>

		</tr>

		<tr>

			<td>您选择的运算符</td>

			<td>

				<select name="fuHao">

					<option value="+">+</option>

					<option value="-">-</option>

					<option value="*">*</option>

					<option value="/">/</option>

				</select>

			</td>

		</tr>

		<tr>

			<td>你输入的第二个数是</td>

			<td><input type="text" name="secondNum"></td>

		</tr>

		<tr>

		<td colspan="2"><input type="submit" value="计算"></td>

		</tr>

	</table>

</form>

</body>

</html>

巴特西

jsp实现计算器

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