Java小项目之：投票系统

Java小项目之：投票系统

今天给大家带来的是java编写的投票小系统，代码简易，适合初学者练手！

代码展示：

package com.tarena.wgh.servlet;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.*;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class PollServlet extends HttpServlet {

/**

 * The doPost method of the servlet. <br>

 *

 * This method is called when a form has its tag value method equals to post.

 *

 * @param request the request send by the client to the server

 * @param response the response send by the server to the client

 * @throws ServletException if an error occurred

 * @throws IOException if an error occurred

 */

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

request.setCharacterEncoding("GBK"); //设置请求的编码方式

String item=request.getParameter("item"); //获取投票项

ServletContext servletContext=request.getSession().getServletContext(); //获取ServletContext对象该对象在application范围内有效

Map map=null;

if(servletContext.getAttribute("pollResult")!=null){

map=(Map)servletContext.getAttribute("pollResult"); //获取投票结果

map.put(item,Integer.parseInt(map.get(item).toString())+1); //将当前的投票项加1

}else{ //初始化一个保存投票信息的Map集合，并将选定投票项的投票数设置为1，其他为0

String[] arr={"基础教程类","实例集锦类","经验技巧类","速查手册类","案例剖析类"};

map=new HashMap();

for(int i=0;i<arr.length;i++){

if(item.equals(arr[i])){ //判断是否为选定的投票项

map.put(arr[i], 1);

}else{

map.put(arr[i], 0);

}

}

}

servletContext.setAttribute("pollResult", map); //保存投票结果到ServletContext对象中

response.setCharacterEncoding("GBK"); //设置响应的编码方式，如果不设置弹出的对话框中的文字将乱码

PrintWriter out=response.getWriter();

out.println("<script>alert('投票成功！');window.location.href='showResult.jsp';</script>");

}

}

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