jsp及servlet分别实现简单的计算器

来源：互联网发布：五行量化指标源码编辑：程序博客网时间：2024/05/30 20:09

本文通过servlet和jsp分别实现计算器的加减乘除运算，下面直接演示代码：

1、servlet实现简单的计算器

1）、CalBean.java 计算器运算的bean封装类

package example.bean.learn;public class CalBean {private double firstParam;private double secondParam;private String operator;private double result;public double getFirstParam() {return firstParam;}public void setFirstParam(double firstParam) {this.firstParam = firstParam;}public double getSecondParam() {return secondParam;}public void setSecondParam(double secondParam) {this.secondParam = secondParam;}public String getOperator() {return operator;}public void setOperator(String operator) {this.operator = operator;}public double getResult() {return result;}public void setResult(double result) {this.result = result;}public double calculate() {result = 0;try {if ("+".equals(operator))result = firstParam + secondParam;if ("-".equals(operator))result = firstParam - secondParam;if ("*".equals(operator))result = firstParam * secondParam;if ("/".equals(operator) && (0 != secondParam))result = firstParam / secondParam;} catch (Exception e) {e.printStackTrace();}return result;}//判断输入的是不是数字public boolean isNum(String str) {return str.matches("^[-+]?(([0-9]+)([.]([0-9]+))?|([.]([0-9]+))?)$");}}

2）、Calculate.java 计算器的servlet类

package example.calculate.learn;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import example.bean.learn.CalBean;/** * Servlet implementation class Calculate */public class Calculate extends HttpServlet {private static final long serialVersionUID = 1L;/** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse *      response) */protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse *      response) */protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {request.setCharacterEncoding("utf-8");response.setCharacterEncoding("utf-8");response.setContentType("text/html");PrintWriter out = response.getWriter();String firstParam = request.getParameter("firstParam");String secondParam = request.getParameter("secondParam");String operator = request.getParameter("operator");CalBean cal = new CalBean();if (firstParam != null && cal.isNum(firstParam) && secondParam != null&& cal.isNum(secondParam)) {if (!firstParam.isEmpty()) {cal.setFirstParam(Double.valueOf(firstParam));}if (!secondParam.isEmpty()) {cal.setSecondParam(Double.valueOf(secondParam));}cal.setOperator(operator);if (cal.getOperator().equals("/") && cal.getSecondParam() == 0.0) {out.println("<html><head>");out.println("<title>" + "简易计算器" + "</title>");out.println("</head>");out.println("<body>");out.println("输入有误，除数不能为零" + "<br>");out.println("<a href='index.html'>返回</a>");out.println("</body>");out.println("</html>");} else {double result = cal.calculate();// request.setAttribute("result", result);// request.setAttribute("firstParam", firstParam);// request.setAttribute("secondParam", secondParam);// request.setAttribute("operator", operator);//// RequestDispatcher dispatcher = request// .getRequestDispatcher("index.jsp");// dispatcher.forward(request, response);out.println("<html><head>");out.println("<title>" + "简易计算器" + "</title>");out.println("</head>");out.println("<body>");out.println(firstParam + " " + operator + " " + secondParam+ "= " + result + "<br>");out.println("<a href='index.html'>返回</a>");out.println("</body>");out.println("</html>");}} else {out.println("<html><head>");out.println("<title>" + "简易计算器" + "</title>");out.println("</head>");out.println("<body>");out.println("输入有误，无法进行计算，请输入数字且除数不能为零" + "<br>");out.println("<a href='index.html'>返回</a>");out.println("</body>");out.println("</html>");}}}

3）、index.html 计算器界面

<!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>简易计算器</title></head><body><form action="Calculate" method="post"><input type="text" name="firstParam" value=""> <select name="operator"><option value="+">+</option><option value="-">-</option><option value="*">*</option><option value="/">/</option></select> <input type="text" name="secondParam" value="">=？ <inputtype="submit" value="计算"></form></body></html>

4）、web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">  <display-name>10.1</display-name>  <welcome-file-list>    <welcome-file>index.html</welcome-file>    <welcome-file>index.htm</welcome-file>    <welcome-file>default.html</welcome-file>    <welcome-file>default.htm</welcome-file>    <welcome-file>default.jsp</welcome-file>  </welcome-file-list>  <servlet>    <servlet-name>Calculate</servlet-name>    <servlet-class>example.calculate.learn.Calculate</servlet-class>  </servlet>  <servlet-mapping>    <servlet-name>Calculate</servlet-name>    <url-pattern>/Calculate</url-pattern>  </servlet-mapping> </web-app>

2、jsp实现简单的计算器,CalBean.java共用

1)、cal.jsp

<%@ 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; utf-8"><title>简单加速器</title></head><body>    <jsp:useBean id="calBean" class="example.bean.learn.CalBean"></jsp:useBean><jsp:setProperty property="*" name="calBean"/><%  calBean.calculate(); %><form action="cal.jsp" method="post"><input type="text" name="firstParam" > <selectname="operator"><option value="+">+</option><option value="-">-</option><option value="*">*</option><option value="/">/</option></select> <input type="text" name="secondParam" /> =<button type="submit">计算</button></form><br>计算结果是：<jsp:getProperty property="firstParam" name="calBean"/><jsp:getProperty property="operator" name="calBean"/><jsp:getProperty property="secondParam" name="calBean"/>=<jsp:getProperty property="result" name="calBean"/></body></html>

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