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最新推荐文章于 2025-07-23 10:52:02 发布

转载最新推荐文章于 2025-07-23 10:52:02 发布 · 95 阅读

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/coderookie0820/archive/2013/05/04/4367483.html

文章标签：

#java #测试

java代码：

//封装计算器数据的bean
public class CalculatorBean {
	
	private String firstNum = "0";
	private char operator ='+';
	private String secondNum ="0";
	private String result;
	
	public String getFirstNum() {
		return firstNum;
	}
	public void setFirstNum(String firstNum) {
		this.firstNum = firstNum;
	}
	public char getOperator() {
		return operator;
	}
	public void setOperator(char operator) {
		this.operator = operator;
	}
	public String getSecondNum() {
		return secondNum;
	}
	public void setSecondNum(String secondNum) {
		this.secondNum = secondNum;
	}
	public String getResult() {
		return result;
	}
	public void setResult(String result) {
		this.result = result;
	}
	
	public void calculator(){
		
		if(!firstNum.matches("^[-+]?(([0-9]+)([.]([0-9]+))?|([.]([0-9]+))?)$")||!secondNum.matches("^[-+]?(([0-9]+)([.]([0-9]+))?|([.]([0-9]+))?)$")){//判断运算参数是否是数字
			throw new RuntimeException("运算参数必须为数字");
		}
		BigDecimal first = new BigDecimal(firstNum);
		BigDecimal second = new BigDecimal(secondNum);
		
		switch(this.operator){
			case '+':{
				this.result = first.add(second).toString();
				break;
			}
			case '-':{
				this.result = first.subtract(second).toString();
				break;
			}
			case '*':{
				this.result = first.multiply(second).toString();
				break;
			}
			case '/':{
				if(second.doubleValue()==0){
					//除数为0,将异常抛出到jsp页面,若抛出异常，后续代码则不执行
					throw new RuntimeException("除数不能为0");
				}
				this.result = first.divide(second,20,BigDecimal.ROUND_HALF_UP).toString();
				break;
			}
			default:
				throw new RuntimeException("运算符只能是：+-*/	");
		}
		
	}
}

jsp代码：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>计算器</title>
  </head>
  
  <body style="text-align:center;">
  
  	<jsp:useBean id="calculatorBean" class="cn.itcast.domain.CalculatorBean"></jsp:useBean>
  	<jsp:setProperty name="calculatorBean" property="*"/>
  	
  	<%
  		try{
  			calculatorBean.calculator();
  		}
  		catch(Exception e){
  			out.write(e.getMessage());
  		}
  	 %>
  	 
  	<br/>=======================================================</br>
  	计算结果是：
  	<jsp:getProperty name="calculatorBean" property="firstNum"/>
  	<jsp:getProperty name="calculatorBean" property="operator"/>
  	<jsp:getProperty name="calculatorBean" property="secondNum"/>
  	=
  	<jsp:getProperty name="calculatorBean" property="result"/>
  	
  	<br/>=======================================================</br>
  
	<br/>  
  
  	<form action="/day09/calculator.jsp" method="post">
	  	<table width="40%" border="1">
	  		<tr>
	  			<td colspan="2">简单计算器</td>
	  		</tr>
	  		<tr>
	  			<td>第一个参数</td>
	  			<td>
	  				<input type="text" name="firstNum" />
	  			</td>
	  		</tr>
	  		<tr>
	  			<td>操作符</td>
	  			<td>
	  				<select name="operator">
	  					<option value="+">+</option>
	  					<option value="-">-</option>
	  					<option value="*">*</option>
	  					<option value="/">/</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>
  </body>
</html>

三层架构原理图：