jsp實現網頁計算器代碼如下：只有兩個jsp頁面
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頁面中不可以直接使用script --> <script language="javascript"> <!-- //寫一個函數判斷是否兩個數都有 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"); return false; } if(Math.round(form1.num1.value) != form1.num1.value) { window.alert("num1不是一個數"); return false; } if(Math.round(form1.num2.value) != form1.num2.value) { window.alert("num2不是一個數"); return false; } } --> </script> </head> <body> <form name="form1" action="calculator/myResult.jsp" method="post"> 請輸入第一個數：<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：<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 String s_num1 = request.getParameter("num1"); //第2步接收到 第2個數 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：
如何判斷輸入的數據是不是數字：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。
希望本文所述對大家學習JSP編程有所幫助。
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