使用jsp+JavaBean简单实现计算器

最新推荐文章于 2021-06-08 22:43:51 发布

iteye_6233

最新推荐文章于 2021-06-08 22:43:51 发布

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文章标签： java

本文介绍如何利用JavaBean和JSP技术在Web应用中实现一个基本的计算器功能，包括创建JavaBean组件、设置属性、进行计算以及通过JSP页面展示计算结果。

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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>