投票系统
实现结果图
（1）JDBC数据库连接工具类conn.java
package com.gx.bean;
import java.sql.*;
public class conn {
public Connection getConn(){
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://localhost:3308/manage","root","yww1352465324");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e){
e.printStackTrace();
}
return conn;
}
public PreparedStatement prepare(Connection conn,String sql){
PreparedStatement pstmt = null;
try{
if (conn != null) {
pstmt = conn.prepareStatement(sql);
}
}catch (SQLException e){
e.printStackTrace();
}
return pstmt;
}
public Statement getStatement(Connection conn){
Statement stmt = null;
try{
if (conn != null) {
stmt = conn.createStatement();
}
}catch (SQLException e){
e.printStackTrace();
}
return stmt;
}
public ResultSet getResultSet(Statement stmt,String sql){
ResultSet rs = null;
if(stmt!=null){
try {
rs = stmt.executeQuery(sql);
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
return rs;
}
public void excuteUpdate(Statement stmt,String sql){
if(stmt!=null){
try {
stmt.executeUpdate(sql);
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
public void close(Connection conn){
if(conn!=null){
try {
conn.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
conn=null;
}
}
public void close(ResultSet rs){
if(rs!=null){
try {
rs.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
rs=null;
}
}
public void close(Statement stmt){
if(stmt!=null){
try {
stmt.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
stmt=null;
}
}
}
（2）web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
</web-app>
（3）index.jsp
<%@ page import="java.sql.ResultSet" %>
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.Statement" %><%--
Created by IntelliJ IDEA.
User: 12526
Date: 2021/1/15
Time: 17:15
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>投票系统</title>
</head>
<body>
<jsp:useBean id="DB" class="com.gx.bean.conn" />
<center>
<h2>您最喜爱的电影是</h2>
<table border bordercolor="#0066ff" bgcolor="#CCFFFF">
<form action="vote.jsp" method="post">
<%
Connection conn = DB.getConn();
Statement stmt = DB.getStatement(conn);
ResultSet rs = DB.getResultSet(stmt,"select * from vote");
while(rs.next()){
out.println("<tr>");
out.println("<td><input type='radio' name='id' value='"+rs.getString("id")+"'>");
out.println(rs.getString("item")+"</td>");
out.println("</tr>");
}
DB.close(conn);
DB.close(stmt);
DB.close(rs);
//session.setMaxInactiveInterval (-1),就是说设置的这个session永远不会失效
session.setMaxInactiveInterval(-1);
%>
<tr><td align="center"><input type="submit" value="投票"></td></tr>
</form>
<tr><td align="center"><a href="info.jsp">查看投票</a></td></tr>
</table>
<p><a href="manage.jsp">投票系统维护</a></p>
</center>
</body>
</html>
（4）add.jsp
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.Statement" %>
<%@ page import="java.sql.ResultSet" %><%--
Created by IntelliJ IDEA.
User: 12526
Date: 2021/1/16
Time: 18:36
To change this template use File | Settings | File Templates.
--%>
<%--<%@ include file="checkadmin.jsp"%>--%>
<%@ page contentType="text/html;charset=utf-8" language="java" %>
<%@ include file="checkadmin.jsp"%>
<html>
<head>
<title>Title</title>
</head>
<body>
<jsp:useBean id="DB" class="com.gx.bean.conn" scope="session"/>
<center>
<h2>系统维护</h2>
<table border bordercolor="#0099FF">
<tr>
<th colspan="3" bgcolor="#CCFFFF">
删除投票项
</th>
<%
Connection conn = DB.getConn();
Statement stmt = DB.getStatement(conn);
ResultSet rs = DB.getResultSet(stmt,"select * from vote");
int i = 1;
while (rs.next()){
out.println("<tr>");
out.println("<td>"+i+"</td>");
out.println("<td>"+rs.getString("item")+"</td>");
out.println("<td align='center'><a href='delete.jsp?delid="+ rs.getString("id") +" '>删除</a></td>");
i++;
}
DB.close(rs);
DB.close(conn);
DB.close(stmt);
%>
</tr>
<tr>
<th colspan="3" bgcolor="#CCFFFF">
添加投票项
</th>
</tr>
<tr>
<td colspan="3">
<form action="add.jsp" method="post">
内容:
<input type="text" name="additem" size="30">
<input type="submit" value="提交">
<input type="reset" value="重置">
</form>
</td>
</tr>
<tr>
<td colspan="3" align="center" bgcolor="#CCFFFF">
<a href="index.jsp">返回投票页面</a>
</td>
</tr>
</table>
</center>
</body>
</html>
（5）login.jsp
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page import="java.sql.Statement" %><%--
Created by IntelliJ IDEA.
User: 12526
Date: 2021/1/16
Time: 12:12
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=utf-8" language="java" %>
<html>
<head>
<title>登录页</title>
</head>
<body>
<jsp:useBean id="DB" class="com.gx.bean.conn" scope="session"/>
<center>
<form action="process.jsp" method="post">
<table>
<tr>
<td width="40%">用 户 名:</td>
<td><input type="text" name="user"></td>
</tr>
<tr>
<td width="40%">密 码:</td>
<td><input type="password" name="pw"></td>
</tr>
<tr>
<td colspan="2" align="center">
<input type="submit" value="登录">
<input type="reset" value="清空">
</td>
</tr>
</table>
</form>
</center>
</body>
<%
String warning = request.getParameter("warning");
if (warning!=null){
warning =new String(warning.getBytes());
out.println("<h3>"+warning+",请重新登录或<a href='index.jsp'>返回首页</a></h3>");
}
%>
</html>
（6）vote.jsp
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.Statement" %>
<%@ page import="java.sql.ResultSet" %><%--
Created by IntelliJ IDEA.
User: 12526
Date: 2021/1/15
Time: 17:47
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title></title>
</head>
<body>
<jsp:useBean id="DB" class="com.gx.bean.conn" />
<%
String id = request.getParameter("id");
Connection conn = DB.getConn();
Statement stmt = DB.getStatement(conn);
ResultSet rs = DB.getResultSet(stmt,"select * from vote where id ="+id);
int num = 0;
if(rs.next()){
num = rs.getInt("count");
System.out.println(num);
}
num++;
System.out.println(num);
//空格一定要书写规范，否则sql语句会失败
String sql = "update vote set count ="+num+" where id="+id+"";
DB.excuteUpdate(stmt,sql);
DB.close(conn);
DB.close(stmt);
DB.close(rs);
%>
<jsp:forward page="info.jsp" />
</body>
</html>
（7）process.jsp
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page import="java.sql.Statement" %><%--
Created by IntelliJ IDEA.
User: 12526
Date: 2021/1/16
Time: 12:14
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=utf-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<jsp:useBean id="DB" class="com.gx.bean.conn" scope="session" />
<%
Connection conn = DB.getConn();
Statement stmt = DB.getStatement(conn);
String user = request.getParameter("user");
String password = request.getParameter("pw");
System.out.println(user);
System.out.println(password);
String sql = "select * from admin where name = '" + user + "' and password = '" + password + "'";
ResultSet rs = DB.getResultSet(stmt,sql);
System.out.println(rs);
if(rs.next()){
DB.close(rs);
DB.close(conn);
DB.close(stmt);
session.setAttribute("admin","ok");
%>
<jsp:forward page="manage.jsp" />
<%
}
else {
rs.close();
DB.close(conn);
DB.close(stmt);
%>
<jsp:forward page="login.jsp">
<jsp:param name="warning" value="对不起，您的用户名或密码不正确" />
</jsp:forward>
</body>
<%
}
%>
</html>
（8）delete.jsp
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.Statement" %>
<%@ page import="java.sql.ResultSet" %><%--
Created by IntelliJ IDEA.
User: 12526
Date: 2021/1/16
Time: 19:38
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>删除投票项</title>
</head>
<body>
<jsp:useBean id="DB" class="com.gx.bean.conn" scope="session"/>
<%
String delid = request.getParameter("delid");
System.out.println(delid);
Connection conn = DB.getConn();
Statement stmt = DB.getStatement(conn);
String sql = "delete from vote where id ="+delid;
if(delid!=null){
DB.excuteUpdate(stmt,sql);
}
DB.close(conn);
DB.close(stmt);
%>
<jsp:forward page="manage.jsp" />
</body>
</html>
（9）checkadmin.jsp
<%--
Created by IntelliJ IDEA.
User: 12526
Date: 2021/1/16
Time: 20:10
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=utf-8" language="java"%>
<html>
<head>
<title>Title</title>
</head>
<body>
<%
if(session.getAttribute("admin") == null){
response.sendRedirect("login.jsp");
}
%>
</body>
</html>
（10）info.jsp
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.Statement" %>
<%@ page import="java.sql.ResultSet" %><%--
Created by IntelliJ IDEA.
User: 12526
Date: 2021/1/15
Time: 20:08
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>投票结果</title>
</head>
<body>
<jsp:useBean id="DB" class="com.gx.bean.conn" />
<center>
<h2>投票结果</h2>
<table border bordercolor="#0099ff">
<tr>
<th bgcolor="#CCFFFF">选项</th>
<th bgcolor="#CCFFFF">得票数</th>
<th bgcolor="#CCFFFF">比例</th>
</tr>
<%
int totalNum =0;
Connection conn = DB.getConn();
Statement stmt = DB.getStatement(conn);
ResultSet rs = DB.getResultSet(stmt,"select count from vote");
while(rs.next()){
totalNum += rs.getInt(1);
}
DB.close(rs);
rs = DB.getResultSet(stmt,"select * from vote");
while (rs.next()){
out.println("<tr>");
int num = rs.getInt("count");
out.println("<td>"+rs.getString("item")+"</td>");
out.println("<td>得:"+num+"票</td>");
out.println("<td>得票率: ");
out.println(num*100/totalNum+"%</td>");
}
DB.close(conn);
DB.close(stmt);
DB.close(rs);
%>
</table>
<p><a href="index.jsp">返回投票页面</a></p>
</center>
</body>
</html>
（11）manage.jsp
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.Statement" %>
<%@ page import="java.sql.ResultSet" %><%--
Created by IntelliJ IDEA.
User: 12526
Date: 2021/1/16
Time: 18:36
To change this template use File | Settings | File Templates.
--%>
<%--<%@ include file="checkadmin.jsp"%>--%>
<%@ page contentType="text/html;charset=utf-8" language="java" %>
<%@ include file="checkadmin.jsp"%>
<html>
<head>
<title>Title</title>
</head>
<body>
<jsp:useBean id="DB" class="com.gx.bean.conn" scope="session"/>
<center>
<h2>系统维护</h2>
<table border bordercolor="#0099FF">
<tr>
<th colspan="3" bgcolor="#CCFFFF">
删除投票项
</th>
<%
Connection conn = DB.getConn();
Statement stmt = DB.getStatement(conn);
ResultSet rs = DB.getResultSet(stmt,"select * from vote");
int i = 1;
while (rs.next()){
out.println("<tr>");
out.println("<td>"+i+"</td>");
out.println("<td>"+rs.getString("item")+"</td>");
out.println("<td align='center'><a href='delete.jsp?delid="+ rs.getString("id") +" '>删除</a></td>");
i++;
}
DB.close(rs);
DB.close(conn);
DB.close(stmt);
%>
</tr>
<tr>
<th colspan="3" bgcolor="#CCFFFF">
添加投票项
</th>
</tr>
<tr>
<td colspan="3">
<form action="add.jsp" method="post">
内容:
<input type="text" name="additem" size="30">
<input type="submit" value="提交">
<input type="reset" value="重置">
</form>
</td>
</tr>
<tr>
<td colspan="3" align="center" bgcolor="#CCFFFF">
<a href="index.jsp">返回投票页面</a>
</td>
</tr>
</table>
</center>
</body>
</html>
项目结构目录
数据库