JSP小实例--计算器

package cn.com.caculate;

import java.math.BigDecimal;

public class caculate {
private String firstNum="0";
private String secondNum="0";
private char operator='+';
private String result="0";
public String getFirstNum() {
return firstNum;
}
public void setFirstNum(String firstNum) {
this.firstNum = firstNum;
}
public String getSecondNum() {
return secondNum;
}
public void setSecondNum(String secondNum) {
this.secondNum = secondNum;
} public char getOperator() {
return operator;
}
public void setOperator(char operator) {
this.operator = operator;
}
public String getResult() {
return result;
}
public void setResult(String result) {
this.result = result;
}
public void calculate()
{
BigDecimal first=new BigDecimal(this.firstNum);
BigDecimal second=new BigDecimal(this.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)
{
throw new RuntimeException("除零异常!");
}
this.result=first.divide(second, 20, BigDecimal.ROUND_HALF_UP).toString();
break;
default:
throw new RuntimeException("操作有错误!");
}
}
}
<%@ 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%>"> <title>My JSP 'calculator.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 style="text-align:center;">
<jsp:useBean id="caculate" class="cn.com.caculate.caculate"></jsp:useBean>
<jsp:setProperty name="caculate" property="*"/>
<%
try{
caculate.calculate();
}
catch(Exception e){ out.write(e.getMessage());
}
%>
<br/>-----------------------------------------------------<br/>
计算结果是:
<jsp:getProperty name="caculate" property="firstNum"/>
<jsp:getProperty name="caculate" property="operator"/>
<jsp:getProperty name="caculate" property="secondNum"/>
=
<jsp:getProperty name="caculate" property="result"/>
<br/>-----------------------------------------------------<br/>
<form action="calculator.jsp" method="post">
<table width="404" border="1">
<tr>
<td colspan="3">简单的计算器</td>
</tr>
<tr>
<td>第一个数</td>
<td>
<input type="text" name="firstNum"/>
</td>
</tr>
<tr>
<td>选择操纵</td>
<td>
<select name="operator">
<option value='+'>+</option>
<option value='-'>-</option>
<option value='*'>*</option>
<option value='/'>/</option>
</select>
</td>
</tr>
<tr>
<td>第二个数</td>
<td>
<input type="text" name="secondNum"/> </td>
</tr>
<tr>
<td colspan="3">
<input type="submit" value="计算"/>
</td>
</tr>
</table>
</form>
</body>
</html>
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