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JSP实现网页计算器

news 来源：原创 2024/5/19 20:54:05

（1）jsp实现网页计算器代码如下：只有两个jsp页面

myCal.jsp如下：

<%@ 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 'myCal.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">


<!-- jsp页面中不可以直接使用script -->
<script language="javascript">
<!--
		//写一个函数判断是否两个数都有
		function checkNum()
		{
			//判断num1 num2是否为空
			if((form1.num1.value == "") ||  (form1.num2.value == ""))
			{
				window.alert("null,不能为空！");
				return false;
			}
			//判断是否是数字
			if(Math.round(form1.num1.value) != form1.num1.value   &&  Math.round(form1.num2.value) != form1.num2.value)
			{
				window.alert("num1和num2不是一个数");
				return false;
			}
			if(Math.round(form1.num1.value) != form1.num1.value)
			{
				window.alert("num1不是一个数");
				return false;
			}
			if(Math.round(form1.num2.value) != form1.num2.value)
			{
				window.alert("num2不是一个数");
				return false;
			}
			
		}
	
	-->
	</script>
</head>
<body>

	<form name="form1" action="calculator/myResult.jsp" method="post">
		请输入第一个数：<input type="text" name="num1"> 
		<select name="flag">
			<option value=+>+</option>
			<option value=->-</option>
			<option value=*>*</option>
			<option value=/>/</option>
		</select> 
		请输入第二个数：<input type="text" name="num2"> 
		<input type="submit" value="计算" οnclick="return checkNum();">
	</form>

</body>
</html>

myResult.jsp如下：

<%@ 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 'myResult.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>
  <%
  	//第1步接收到 第1个数
  	String s_num1 = request.getParameter("num1");
  	//第2步接收到 第2个数
  	String s_num2 = request.getParameter("num2");
  	//第3步接收到 运算符
  	String flag = request.getParameter("flag");
  	//第4步 计算
  	
  	int num1 = Integer.parseInt(s_num1);
  	int num2 = Integer.parseInt(s_num2);
  	int result = 0;
  	if(flag.equals("+"))
  	{
  		result = num1+num2;
  	}
  	else if(flag.equals("-"))
  	{
  		result = num1-num2;
  	}
  	else if(flag.equals("*"))
  	{
  		result = num1*num2;
  	}
  	else if(flag.equals("/"))
  	{
  		result = num1/num2;
  	}
  	//第5步
  	out.println("结果是:"+result);
   %>  
    
  </body>
</html>

（2）虽然过程很简单但是有几个值得学习的地方：

如何判断输入的数据是不是数字：使用Math.round(form1.num1.value) != form1.num1.value 来判断；

如何获取操作值：设置name属性 flag实现；