基于Servlet+jsp的web计算器
这次老大为了让我们自己复习web中页面的跳转给布置得任务
天下代码一大抄，关键看你怎么抄
首先我想到的计算算法不是什么堆栈，是简单的（其实很复杂，但是我就只需要知道有这个东西，东西别人做好了...传说中的CV大法好？Emmm，当你知道有这么个算法但是不会自己写可是自己会用的时候，也就相当于...自己会了.....）
废话不多说一下是收集的正则工具类，支持括号运算
package pers.cal.util;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class UtilArithmetic {
// public static void main(String[] args) {
// String src = "(3 + (5 - 2) * 10 / 2 * 3 + 15) * (8 - 4)";
// System.out.println(cal(src));
// }
public static String cal(String src) {
StringBuilder builder = new StringBuilder();
if (src.contains("(")) {
Pattern pattern = Pattern.compile("\\(([^()]+)\\)");
Matcher matcher = pattern.matcher(src);
int lastEnd = 0;
while (matcher.find()) {
builder.append(src.substring(lastEnd, matcher.start()));
System.out.println(builder.toString());
builder.append(cal(matcher.group(1)));
lastEnd = matcher.end();
}
builder.append(src.substring(lastEnd));
} else {
Pattern pattern = Pattern.compile("([\\d.]+)\\s*([*/])\\s*([\\d.]+)");
builder.append(src);
Matcher matcher = pattern.matcher(builder.toString());
while (matcher.find()){
float f1 = Float.parseFloat(matcher.group(1));
float f2 = Float.parseFloat(matcher.group(3));
float result = 0;
switch (matcher.group(2)){
case "*":
result = f1 * f2;
break;
case "/":
result = f1 / f2;
break;
}
builder.replace(matcher.start(), matcher.end(),
String.valueOf(result));
matcher.reset(builder.toString());
}
pattern = Pattern.compile("([\\d.]+)\\s*([+-])\\s*([\\d.]+)");
matcher = pattern.matcher(builder.toString());
while (matcher.find()){
float f1 = Float.parseFloat(matcher.group(1));
float f2 = Float.parseFloat(matcher.group(3));
float result = 0;
switch (matcher.group(2)){
case "+":
result = f1 + f2;
break;
case "-":
result = f1 - f2;
break;
}
builder.replace(matcher.start(), matcher.end(),
String.valueOf(result));
matcher.reset(builder.toString());
}
return builder.toString();
}
System.out.println(builder);
return cal(builder.toString());
}
}
调用的时候直接用cal(String str)就好
然后是对应的前台jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
基于Servlet+jsp的Web计算器的项目
金 聖 聰 ®
他的css
html {
font-size: 62.5%;
box-sizing: border-box;
margin: 0;
padding: 0;
box-sizing: inherit
}
body {
width: 100vw;
min-height: 100vh;
background-color: #B0C4DE;
display: flex;
justify-content: center;
align-items: center;
}
.calculator {
background: #1d1e22;
padding:2.8rem .64rem .64rem;
color: white;
border-radius: .5rem;
box-shadow: 0 .3rem 3rem .1rem rgba(0,0,0,0.6);
position: relative;
min-width: 40rem;
}
.calculator-display {
font-size: 5rem;
height: 80px;
padding: 0 20px;
background-color: #1d1e22;
color: #fff;
display: flex;
align-items: center;
justify-content: flex-end;
}
#result{
color:white;
background-color:#003300;
width:100%;
height:50%;
font-size:33%;
text-align:right;
}
button {
height: 60px;
border-radius: 3px;
border: 1px solid #c4c4c4;
font-size: 2rem;
background-color: #fff;
}
.calculator-keys {
display: grid;
grid-gap: 2rem;
padding: 2rem 1.36rem;
background-color: #fff;
}
.equal-sign {
grid-row: 5 / span 1;
grid-column: 3 / 5;
height: 100%;
}
.copyRight{
text-align: center;
display:block;
color:black;
font-weight:bolder;
font-size: 33px;
}长这个样子
用到了El表达式
相关jar包
xml配置
Calculation
ServletDemo
pers.cal.servlet.CalculationServlet
ServletDemo
/calculator.do
对应的Servlet
package pers.cal.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import pers.cal.util.UtilArithmetic;
public class CalculationServlet extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String result = req.getParameter("result");
// req.setAttribute("result", "admin");
String finalRes = result;
result = finalRes+"="+UtilArithmetic.cal(result);
HttpSession session = req.getSession();
session.setAttribute("count",result);
System.out.println(result);
req.getRequestDispatcher("index.jsp").forward(req, resp);
}
}
最后是结构
晚安。
做个好梦
おやすみ～