使用jsp+JavaBean简单实现计算器

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1、实现javabean

package cn.csdn.web.domain;import java.math.BigDecimal;public class Calculate {private Double firstNum;private char operator;private Double secondNum;private Double result;public Calculate() {super();}public Double getFirstNum() {return firstNum;}public void setFirstNum(Double firstNum) {this.firstNum = firstNum;}public char getOperator() {return operator;}public void setOperator(char operator) {this.operator = operator;}public Double getSecondNum() {return secondNum;}public void setSecondNum(Double secondNum) {this.secondNum = secondNum;}public Double getResult() {return result;}public void setResult(Double result) {this.result = result;}public Double calculate() {switch (this.operator) {case '+':this.result = this.firstNum + this.secondNum;break;case '-':this.result = this.firstNum - this.secondNum;break;case '*':this.result = this.firstNum * this.secondNum;break;case '/':if (this.secondNum == 0) {System.out.println("除数不能为零");} else {this.result = this.firstNum / this.secondNum;BigDecimal bigDecimal = new BigDecimal(this.result);bigDecimal = bigDecimal.setScale(2, BigDecimal.ROUND_HALF_UP);this.result = bigDecimal.doubleValue();}break;default:System.out.println("无法判断");break;}return result;}}

2、实现jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme() + "://"+ request.getServerName() + ":" + request.getServerPort()+ path + "/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><base href="<%=basePath%>"><style>table {border-collapse: collapse;}</style><title>My JSP 'calculate.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><div align="center"><h1>计算哭器简单实现</h1><hr color="red"><div><!-- 创建一个javabean组件 --><jsp:useBean id="calculate" class="cn.csdn.web.domain.Calculate"></jsp:useBean><jsp:setProperty property="*" name="calculate" /><%calculate.calculate();%>计算结果是：<jsp:getProperty property="firstNum" name="calculate" /><jsp:getProperty property="operator" name="calculate" /><jsp:getProperty property="secondNum" name="calculate" />=<jsp:getProperty property="result" name="calculate" /></div><form action="./calculate.jsp" method="post"><table border="1px"><caption>计算器</caption><tr><td colspan="2"></td></tr><tr><td>第一个参数：</td><td><input type="text" name="firstNum" /></td></tr><tr><td>运算符</td><td><select name="operator"><option selected="selected">+</option><option>-</option><option>*</option><option>/</option></select></td></tr><tr><td>第二个参数：</td><td><input type="text" name="secondNum" /></td></tr><tr><td colspan="2"><input type="submit" value="计算" /></td></tr></table></form></div></body></html>