<%@ 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頁面中不可以直接使用script --> 
<script language="javascript"> 
<!-- 
  //寫一個函數(shù)判斷是否兩個數(shù)都有 
  function checkNum() 
  { 
   //判斷num1 num2是否為空 
   if((form1.num1.value == "") || (form1.num2.value == "")) 
   { 
    window.alert("null,不能為空！"); 
    return false; 
   } 
   //判斷是否是數(shù)字 
   if(Math.round(form1.num1.value) != form1.num1.value && Math.round(form1.num2.value) != form1.num2.value) 
   { 
    window.alert("num1和num2不是一個數(shù)"); 
    return false; 
   } 
   if(Math.round(form1.num1.value) != form1.num1.value) 
   { 
    window.alert("num1不是一個數(shù)"); 
    return false; 
   } 
   if(Math.round(form1.num2.value) != form1.num2.value) 
   { 
    window.alert("num2不是一個數(shù)"); 
    return false; 
   } 
    
  } 
  
 --> 
 </script> 
</head> 
<body> 
 
 <form name="form1" action="calculator/myResult.jsp" method="post"> 
  請輸入第一個數(shù)：<input type="text" name="num1"> 
  <select name="flag"> 
   <option value=+>+</option> 
   <option value=->-</option> 
   <option value=*>*</option> 
   <option value=/>/</option> 
  </select> 
  請輸入第二個數(shù)：<input type="text" name="num2"> 
  <input type="submit" value="計算" onclick="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個數(shù) 
 String s_num1 = request.getParameter("num1"); 
 //第2步接收到 第2個數(shù) 
 String s_num2 = request.getParameter("num2"); 
 //第3步接收到 運算符 
 String flag = request.getParameter("flag"); 
 //第4步 計算 
  
 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("結果是:"+result); 
 %> 
  
 </body> 
</html>

雖然過程很簡單但是有幾個值得學習的地方：
如何判斷輸入的數(shù)據(jù)是不是數(shù)字：使用Math.round(form1.num1.value) != form1.num1.value 來判斷；
如何獲取操作值：設置name屬性 flag實現(xiàn)。

希望本文所述對大家學習JSP編程有所幫助。

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