JSP学习笔记---应用做个简易计算器JSP+javabean

来源：互联网发布：福州哪里可以学编程编辑：程序博客网时间：2024/06/05 10:12

注意：

1.用到了<jsp:setProperty property="*" name="calculate"/>标签，注意javabean中参数变量务必要与表单提交数据名称相同。

Main.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>My JSP 'Main.jsp' starting page</title>  </head>    <body>    <jsp:useBean id="calculate"   class="com.wanhao.Calculate"/>  <jsp:setProperty property="*" name="calculate"/><%     calculate.calculate();     out.write(calculate.getFirstNum()+calculate.getOperator()+calculate.getSecondNum()+"="+calculate.getResult()); %> <form  action="/Calculate/Main.jsp"  method="post">输入第一个数：<input type="text" name="firstNum">选择操作：<select name="operator">      <option>+      <option>-      <option>*      <option>/</select>输入第二个数：<input type="text" name="secondNum"><input type="submit" name="计算"   ></form>   </body></html>

Calculate.java

package com.wanhao;import java.math.BigDecimal;public class Calculate {    String firstNum="0";    char operator='+';    String secondNum="0";    String result="0";public char getOperator() {return operator;}public void setOperator(char operator) {this.operator = operator;}public String getResult() {return result;}public void setResult(String result) {this.result = result;}public String getFirstNum() {return firstNum;}public void setFirstNum(String firstNum) {this.firstNum = firstNum;}public String getSecondNum() {return secondNum;}public void setSecondNum(String secondNum) {this.secondNum = secondNum;}public void calculate(){BigDecimal  number1=new BigDecimal(firstNum);BigDecimal number2=new BigDecimal(secondNum);         switch(operator)         {         case '+':  result=number1.add(number2).toString();break;         case '-':   result=number1.subtract(number2).toString();break;         case '*':   result=number1.multiply(number2).toString();break;         case '/':   result=number1.divide(number2, 10, BigDecimal.ROUND_UP).toString();break;         default:  result="0";         }}    }

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