使用jsp調(diào)用javabean實(shí)現(xiàn)超簡(jiǎn)單網(wǎng)頁(yè)計(jì)算器示例

package com.amos.model;

import java.math.BigDecimal;

/**
* @ClassName: Calculator
* @Description: 計(jì)算器
* @author: amosli
* @email:amosli@infomorrow.com
* @date Mar 20, 2014 1:04:59 AM 
*/
public class Calculator {
    private String firstnum="0";
    private String secondnum="0";
    private char operator='+';
    private String result;

    public String getResult() {
        return result;
    }

    public char getOperator() {
        return operator;
    }

    public void setOperator(char operator) {
        this.operator = operator;
    }

    public void setResult(String result) {
        this.result = result;
    }

    public String getFirstnum() {
        return firstnum;
    }

    public void setFirstnum(String firstnum) {
        this.firstnum = firstnum.trim();
    }

    public String getSecondnum() {
        return secondnum;
    }

    public void setSecondnum(String secondnum) {
        this.secondnum = secondnum.trim();
    }

    public void calculate() {
        BigDecimal a = new BigDecimal(this.firstnum);
        BigDecimal b = new BigDecimal(this.secondnum);
        switch (this.operator) {
        case '+':
            this.result = a.add(b).toString();
            break;
        case '-':
            this.result = a.subtract(b).toString();
            break;
        case '*':
            this.result = a.multiply(b).toString();
            break;
        case '/':
            if (b.doubleValue()==0) {
                throw new RuntimeException("被除數(shù)不能為零");
            }
            this.result = a.divide(b,10,BigDecimal.ROUND_HALF_DOWN).toString();
            break;
        default:
            break;
        }
    }
}

%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
title>jsp計(jì)算器/title>
/head>
body>
    jsp:useBean id="calcBean" class="com.amos.model.Calculator">/jsp:useBean>
    jsp:setProperty property="*" name="calcBean" />
    %
        calcBean.calculate();
    %>
    hr>
    計(jì)算結(jié)果是:
    jsp:getProperty property="firstnum" name="calcBean" />
    jsp:getProperty property="operator" name="calcBean" />
    jsp:getProperty property="secondnum" name="calcBean" />
    =jsp:getProperty property="result" name="calcBean" />
    hr>
    form action="/jsp/calculator.jsp" method="post">
        table style="text-align: center;">
            tr>
                td colspan="2">簡(jiǎn)單的計(jì)算器/td>
            /tr>
            tr>
                td>第一個(gè)參數(shù)/td>
                td>input type="text" name="firstnum" />/td>
            /tr>
            tr>
                td>select name="operator">
                        option value="+">+/option>
                        option value="-">-/option>
                        option value="*">*/option>
                        option value="/">//option>
                /select>/td>
            /tr>
            tr>
                td>第二個(gè)數(shù)/td>
                td>input type="text" name="secondnum" />/td>
            /tr>
            tr>
                td>
                    button name="calc" type="submit">計(jì)算/button>
                /td>
            /tr>
        /table>
    /form>
/body>
/html>

0.1+0.02=0.12000000000000001

error-page>
      exception-type>java.lang.Exception/exception-type>
      location>/error/error.jsp/location>
  /error-page>

sorry,出錯(cuò)了!!
    %out.print(exception.getMessage()); %>