javaweb15

bean.jdbc

package bean;
import java.sql.*;


public class jdbc {
static Connection conn=null;
public static   Connection getConnection() throws ClassNotFoundException, SQLException {
String user="root";
String drivername="com.mysql.jdbc.Driver";
String usepwd="test";
String dbname="sys";
String url1="jdbc:mysql://localhost:3306/"+dbname;
String url2="?user="+user+"&password="+usepwd;
String url3="&useUnicode=true&characterEncoding=UTF-8";
String url=url1+url2+url3;
Class.forName(drivername);
try{conn=DriverManager.getConnection(url);
return conn;}catch(Exception e) {
e.printStackTrace();
return null;
}
}
public static void free(ResultSet rs,Statement st,Connection conn)
{  
    try
    { 
        if(rs!=null)              
            rs.close();                       
    }catch (SQLException e) 
    { 
        e.printStackTrace();  
    }finally{
             try
             {
                 if(st!=null)
                     st.close();                 
             }catch (SQLException e) { e.printStackTrace();  
             } finally{
                 if(conn!=null)                       
                     try
                 { 
                         conn.close();  
                 }
                 catch (SQLException e) {  
                     e.printStackTrace();  
                  }  
                 }   
               }
    }

}

bean.Dao

package bean;


import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;


public class Dao {
public int pd(String id, String pw) throws Exception {
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
conn = jdbc.getConnection();
String sql = "select * from web5";
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
String id1 = rs.getString(1);
if (id1.equals(id)) {
String pwd1 = rs.getString(2);
if (pwd1.equals(pw)) {
return 1;
}
}
}


return 0;
}
public void update(String rank) throws ClassNotFoundException, SQLException {
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
conn = jdbc.getConnection();
String sql = "select * from web15 where rank=?";
ps = conn.prepareStatement(sql);
ps.setString(1, rank);
rs = ps.executeQuery();
rs.next();
int n=rs.getInt("pnum");
n++;
String sql2="update web15 set pnum=? where rank=?";
PreparedStatement ps1=conn.prepareStatement(sql2);
ps1.setInt(1, n);
ps1.setString(2, rank);
ps1.executeUpdate();


}

}

servelet.servelet

package servelet;


import java.io.IOException;
import java.io.PrintWriter;


import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


import bean.Dao;


/**
 * Servlet implementation class servelet
 */
@WebServlet("/servelet")
public class servelet extends HttpServlet {
private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public servelet() {
        super();
        // TODO Auto-generated constructor stub
    }


/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
}


/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html; charset=utf-8");
String id=request.getParameter("id");
String pwd=request.getParameter("pwd");
   PrintWriter out=response.getWriter();
Dao d=new Dao();
try {
int n=d.pd(id, pwd);
if(n==0) {
out.print("账号密码错误");
}
else {
RequestDispatcher rd=request.getRequestDispatcher("web15-1.jsp");
rd.forward(request, response);
}
} catch (Exception e) {
e.printStackTrace();
}

}

}

web15.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; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="servelet" method="post">
<div align="center">
<h1>候选人投票系统</h1>
<br><br><br><br><br><br>
请输入账号:<input name="id"><br><br>
请输入密码:<input name="pwd"><br><br>
<input type="submit"value="登录">
</div>
</form>
</body>

</html>

web15-1.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; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="web15-2.jsp">
<div align="center">
<h2>请投票</h2>
<br><br><br><br><br>
<input type="radio" name="rank" value="1">&nbsp&nbsp小明<br>
<input type="radio" name="rank" value="2">&nbsp&nbsp小烈<br>
<input type="radio" name="rank" value="3">&nbsp&nbsp小华<br>
<input type="radio" name="rank" value="4">&nbsp&nbsp小丽<br>
<br>
<input type="submit" value="投票">
</div>
</form>
</body>

</html>

web15-2.jsp

<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.PreparedStatement"%>
<%@page import="java.sql.Connection"%>
<%@page import="bean.Dao" import="bean.jdbc"%>
<%@ 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; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
String rank=request.getParameter("rank");
Dao d=new Dao();
d.update(rank);
%>
<br><br><br><br><br><br><br><br>
<div align="center">
<h2>投票成功，谢谢您的参与<br>
<a href="web15-3.jsp">查看投票结果</a></h2>
</div>
</body>

</html>

web15-3.jsp

<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.PreparedStatement"%>
<%@page import="bean.jdbc"%>
<%@page import="java.sql.Connection"%>
<%@ 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; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<br><br><br><br><br><br><br><br>
<table border="1"align="center" valign="center" width="150px">
<tr><td>赛号</td><td>姓名</td><td>票数</td></tr>
<%
Connection conn=jdbc.getConnection();
conn = jdbc.getConnection();
String sql = "select * from web15";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet rs = ps.executeQuery();
while(rs.next()){%>
<tr>
<td><%=rs.getInt("rank") %></td>
<td><%=rs.getString("name") %></td>
<td><%=rs.getInt("pnum") %></td>
</tr>
<%}
%>
</table>
</body>
</html>