基于表单的投票系统--MySql ,DAO ,VO_MySQL
- WBOYOriginal
- 2016-06-01 13:09:451092browse
一。系统分析
只要一个界面 ，但是建议写两个，一个用于显示投票界面 ，一个用于接受用户的投票，将所对应的老师得票加1 ，
工作完了再回到前一个界面 。
各个页面与作用：
VoteDao.java 连接数据库，查询老师的编号 ，姓名 ，得票，修改老师的得票数，将编号对应的得票 数加 1
Vote.java 封装老师的编号 ，姓名 ，得票 数
display.jsp 调用VoteDao查询老师编号 ，姓名 ，得票数，并显示
vote.jsp 获得request 传送 过来的老师编号数组 ，调用 VoteDao 将每个编号对应的得票数加1 ，回到display.jsp
二。数据库初始化
属性：teacherno teachername votenumber
在mySQL中写成脚本运行，用source 命令。
use test;create table t_vote( teacherno varchar(20), teachername varchar(20), vote int );insert into t_vote values('1', 'lishengjing',1);insert into t_vote values('2', 'huangwenjun',1);insert into t_vote values('3', 'zhaosy',2);insert into t_vote values('4', 'chaoshehn',3); 三。java 代码
要将MySQL的驱动复制到 web-inf/lib中，将bar.jpg 复制到WebRoot下的img目录。导入包时最好用 import java.sql*;
public class VoteDao { private Connection conn=null; public void initConnection() throws Exception{ Class.forName("com.mysql.jdbc.Driver"); String url ="jdbc:mysql://localhost:3306/test"; conn = DriverManager.getConnection(url , "root","root"); } public ArrayList getAllVotes()throws Exception{ ArrayList all = new ArrayList (); initConnection(); String sql = "select * from t_vote"; Statement stat= conn.createStatement(); ResultSet rs = stat.executeQuery(sql); while (rs.next()){ Vote vote = new Vote(); vote.setTeacherno(rs.getString("teacherno")); vote.setTeachername(rs.getString("teachername")); vote.setVotenumber(rs.getInt("vote")); all.add(vote); } clossConnection(); return all; } public void updateVotes(String [] teacherno )throws Exception{ initConnection(); String sql = "update t_vote set vote=vote+1 where teacherno=?"; PreparedStatement ps = conn.prepareStatement(sql); for (int i =0;i<teacherno.length;i++){ ps.setString(1, teacherno[i]); ps.executeUpdate(); } clossConnection(); } public void clossConnection ()throws Exception{ conn.close(); }} 四。JSP代码部分
display.jsp
<body> <form action ="vote.jsp" method ="post"> <table align="center"> <caption> 欢迎投票<input type="submit" value="提交"> </caption> <tr bgcolor="yellow"> <td>编号</td> <td>姓名</td> <td>得票数</td> </tr> <% VoteDao vdao= new VoteDao(); ArrayList votes = vdao.getAllVotes(); for (int i=0;i<votes.size();i++){ Vote vote =(Vote) votes.get(i); %> <tr bgcolor="pink"> <td><%=vote.getTeacherno()%></td> <td><%=vote.getTeachername()%></td> <td><img src ="img/bar.jpg" style="max-width:90%"基于表单的投票系统--MySql ,DAO ,VO_MySQL" >" height ="10"/> <%=vote.getVotenumber() %></td> <td><input name="teacherno" type="checkbox" value="<%=vote.getTeacherno()%>"></td> </tr> <% } %> </table> </form> </body> vote,jsp
<body> <% String [] teacherno = request.getParameterValues("teacherno") ; VoteDao vdao = new VoteDao(); vdao.updateVotes(teacherno); %> <jsp:forward page="display.jsp"></jsp:forward> </body> Statement：
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Previous article：centos 下安装 mysql 5.6_MySQLNext article：MySQL存储过程中的IN，OUT，INOUT类型_MySQL