1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
2 <%
3 String path = request.getContextPath();
4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
5 %>
6
7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
8 <html>
9 <head>
10 <base href="<%=basePath%>">
11
12 <title>My JSP ‘Calculator.jsp‘ starting page</title>
13
14
15 </head>
16
17 <body>
18
19 <jsp:useBean id="Calculator" class="cn.itcast.domain.Calculator"></jsp:useBean>
20 <jsp:setProperty property="*" name="Calculator"/>
21
22 <%
23 try{
24 Calculator.calculate();
25 }catch(Exception e){
26 out.write(e.getMessage());
27 }
28 %>
29
30 <br/>--------------------------------------------<br/>
31 计算的结果是：
32 <jsp:getProperty name="Calculator" property="firstnum"/>
33 <jsp:getProperty name="Calculator" property="operator"/>
34 <jsp:getProperty name="Calculator" property="secondnum"/>
35 =
36 <jsp:getProperty name="Calculator" property="result"/>
37 <br/>--------------------------------------------<br/>
38 <br/>
39 <form action="/JSPDemo/Calculator.jsp" method="post" style="text-align:center;">
40 <table width="40%" border="1">
41 <tr>
42 <td colspan="2">简单的计算器</td>
43 </tr>
44 <tr>
45 <td>第一个参数</td>
46 <td>
47 <input type="text" name="firstnum" />
48 </td>
49 </tr>
50 <tr>
51 <td>操作符</td>
52 <td>
53 <select name="operator" >
54 <option value="+">+</option>
55 <option value="-">-</option>
56 <option value="*">*</option>
57 <option value="/">/</option>
58 </select>
59 </td>
60 </tr>
61 <tr>
62 <td>第二个参数</td>
63 <td>
64 <input type="text" name="secondnum" />
65 </td>
66 </tr>
67 <tr>
68 <td colspan="2">
69 <input type="submit" value="计算" />
70 </td>
71 </tr>
72 </table>
73 </form>
74
75 </body>
76 </html>
Calculator.jsp
1 package cn.itcast.domain;
2
3
4 import java.math.BigDecimal;
5
6 //封装计算器数据的bean
7 public class Calculator {
8
9 private String firstnum = "0";
10 private String secondnum = "0";
11 private char operator = ‘+‘;
12 private String result;
13
14 public void calculate(){
15 BigDecimal first = new BigDecimal(this.firstnum);
16 BigDecimal second = new BigDecimal(this.secondnum);
17
18 switch(this.operator){
19 case ‘+‘:{
20 this.result = first.add(second).toString();
21 break;
22 }
23 case ‘-‘:{
24 this.result = first.subtract(second).toString();
25 break;
26 }
27 case ‘*‘:{
28 this.result = first.multiply(second).toString();
29 break;
30 }
31 case ‘/‘:{
32 if(second.doubleValue()==0){
33 throw new RuntimeException("被除数不能为0");
34 }
35 this.result = first.divide(second,20,BigDecimal.ROUND_HALF_UP).toString();
36 break;
37 }
38
39 default:
40 throw new RuntimeException("运算符只能+-*/");
41 }
42
43 }
44
45 public String getFirstnum() {
46 return firstnum;
47 }
48
49 public void setFirstnum(String firstnum) {
50 this.firstnum = firstnum;
51 }
52
53 public String getSecondnum() {
54 return secondnum;
55 }
56
57 public void setSecondnum(String secondnum) {
58 this.secondnum = secondnum;
59 }
60
61 public char getOperator() {
62 return operator;
63 }
64
65 public void setOperator(char operator) {
66 this.operator = operator;
67 }
68
69 public String getResult() {
70 return result;
71 }
72
73 public void setResult(String result) {
74 this.result = result;
75 }
76 }
Calculator
jsp开发模式和web计算器案例
时间： 2024-11-18 05:25:12