<%@ page language="java" pageEncoding="UTF-8"%>
<%@ page isErrorPage="true"%>
<%@ page errorPage="calculator.jsp" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>简单的计算机</title>
</head>
<body>
<%--创建Calculator对象--%>
<jsp:useBean id="cal" class="cn.zq.domain.Calculator" />
<%--设置值 通配符*表示设置所有属性--%>
<jsp:setProperty property="*" name="cal"/>
<%--
进行计算
--%>
<c:if test="${empty pageContext.exception}">
<%
cal.calculate();
%>
</c:if>
<hr/>
<p>计算结果：${cal.firstNum } ${cal.operator } ${cal.secondNum } = ${cal.result }</p>
<hr/>
<%--
构建url
--%>
<c:url var="formUrl" value="/calculator.jsp"/>
<form action="${formUrl }" method="post">
<table border="1" cellpadding="2">
<tr>
<td colspan="2" align="center">我的计算器</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 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>本文使用的javabean代码如下：
package cn.zq.domain;
public class Calculator {
private String firstNum;
private String operator;
private String secondNum;
private String result;
public String getFirstNum() {
return firstNum;
}
public void setFirstNum(String firstNum) {
this.firstNum = firstNum;
}
public String getOperator() {
return operator;
}
public void setOperator(String 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 Calculator() {}
public Calculator(String firstNum, String operator, String secondNum,
String result) {
this.firstNum = firstNum;
this.operator = operator;
this.secondNum = secondNum;
this.result = result;
}
public void calculate(){
if(operator != null && !operator.equals("")){
double first = new Double(firstNum);
double second = new Double(secondNum);
char oper = operator.charAt(0);
switch (oper) {
case '+':
result = first + second + "";
break;
case '-':
result = first - second + "";
break;
case '*':
result = first * second + "";
break;
case '/':
result = first / second + "";
break;
default:
throw new RuntimeException("未知运算符!");
}
}
}
}最终完成的效果图如下：
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