JSP MVC模式案例之投票系统

      create table voteitems(
      	id number(8) primary key,
      	item varchar2(50) not null,
      	times number(8) default 0
      );
      create sequence seq_voteitems;
      insert into voteitems(id,item) values (seq_voteitems.nextval,'jsp');
      insert into voteitems(id,item) values (seq_voteitems.nextval,'asp');
      insert into voteitems(id,item) values (seq_voteitems.nextval,'asp.net');
      insert into voteitems(id,item) values (seq_voteitems.nextval,'php');
      commit;
  
 

      package com.javaweb.dao.util;
      import java.sql.Connection;
      import java.sql.DriverManager;
      import java.sql.ResultSet;
      import java.sql.SQLException;
      import java.sql.Statement;
      public class BaseDao {
     	private static String url = "jdbc:oracle:thin:@localhost:1521:orcl";
     	private static String driver = "oracle.jdbc.driver.OracleDriver";
     	private static String user="scott";
     	private static String pwd = "tiger";
     	public static Connection getConnection()
     		throws ClassNotFoundException, SQLException{
      		Class.forName(driver);
     		Connection con = DriverManager.getConnection(url,user,pwd);
     		return con;
      	}
     	public static void closeAll(ResultSet rs,Statement stmt,Connection con)
     		throws SQLException{
     		if(rs!=null)
      			rs.close();
     		if(stmt!=null)
      			stmt.close();
     		if(con!=null)
      			con.close();
      	}
      }
  
 

       package com.javaweb.dao;
       import java.util.List;
       import com.javaweb.entity.VoteItems;
       public interface VoteItemsDao {
      	public List<VoteItems> findAll();
      	public boolean update(int id);
       }
   
 

      package com.javaweb.dao.impl;
      import java.sql.Connection;
      import java.sql.PreparedStatement;
      import java.sql.ResultSet;
      import java.sql.SQLException;
      import java.util.ArrayList;
      import java.util.List;
      import com.javaweb.dao.VoteItemsDao;
      import com.javaweb.dao.util.BaseDao;
      import com.javaweb.entity.VoteItems;
      public class VoteItemsDaoImpl extends BaseDao implements VoteItemsDao {
     	public static void main(String[] args) {
      		System.out.println(new VoteItemsDaoImpl().findAll().size());
      	}
     	public List<VoteItems> findAll() {
     		Connection con = null;
     		PreparedStatement pstmt = null;
      		ResultSet rs=null;
      		List<VoteItems> items=null;
      		String sql="select id,item,times from voteitems";
     		try {
      			con=getConnection();
      			items=new ArrayList<VoteItems>();
      			pstmt=con.prepareStatement(sql);
      			rs=pstmt.executeQuery();
     			while(rs.next()){
      				VoteItems item=new VoteItems();
      				item.setId(rs.getInt(1));
      				item.setItem(rs.getString(2));
      				item.setTimes(rs.getInt(3));
      				 items.add(item);
      			}
      		} catch (ClassNotFoundException e) {
      			e.printStackTrace();
      		} catch (SQLException e) {
      			e.printStackTrace();
      		}finally{
     			try {
      				closeAll(rs, pstmt, con);
      			} catch (SQLException e) {
     				// TODO Auto-generated catch block
      				e.printStackTrace();
      			}
      		}
     		return  items;
      	}
     	public boolean update(int id) {
     		String sql = "update voteitems set times = times + 1 where id = "+id;
     		Connection con = null;
     		PreparedStatement pstmt = null;
     		int n = -1;
     		try {
      			con = getConnection();
      			pstmt = con.prepareStatement(sql);
      			n=pstmt.executeUpdate();
      		} catch (ClassNotFoundException e) {
     			// TODO Auto-generated catch block
      			e.printStackTrace();
      		} catch (SQLException e) {
     			// TODO Auto-generated catch block
      			e.printStackTrace();
      		}finally{
     			try {
      				closeAll(null, pstmt, con);
      			} catch (SQLException e) {
     				// TODO Auto-generated catch block
      				e.printStackTrace();
      			}
      		}
     		return n>0;
      	}
      }
  
 

      package com.javaweb.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 com.javaweb.dao.VoteItemsDao;
      import com.javaweb.dao.impl.VoteItemsDaoImpl;
      public class UpdateVoteServlet extends HttpServlet {
     	/**
       * The doGet method of the servlet. <br>
       *
       * This method is called when a form has its tag value method equals to get.
       *
       * @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 doGet(HttpServletRequest request, HttpServletResponse response)
     			throws ServletException, IOException {
      		doPost(request, response);
      	}
     	/**
       * 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 {
      		String[] strItems = request.getParameterValues("items");
     		VoteItemsDao dao = new VoteItemsDaoImpl();
     		for(String item:strItems){
      			dao.update(Integer.parseInt(item));
      			System.out.println(item);
      		}
      // 
       		response.sendRedirect("ShowVoteServlet");
     		//request.getRequestDispatcher("ShowVoteServlet").forward(request, response);
      	}
      }
  
 

      package com.javaweb.servlet;
      import java.io.IOException;
      import java.util.List;
      import javax.servlet.ServletException;
      import javax.servlet.http.HttpServlet;
      import javax.servlet.http.HttpServletRequest;
      import javax.servlet.http.HttpServletResponse;
      import com.javaweb.dao.VoteItemsDao;
      import com.javaweb.dao.impl.VoteItemsDaoImpl;
      import com.javaweb.entity.VoteItems;
      public class ShowVoteServlet extends HttpServlet {
     	/**
       * The doGet method of the servlet. <br>
       *
       * This method is called when a form has its tag value method equals to get.
       *
       * @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 doGet(HttpServletRequest request, HttpServletResponse response)
     			throws ServletException, IOException {
      		doPost(request, response);
      	}
     	/**
       * 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 {
     		VoteItemsDao dao = new VoteItemsDaoImpl();
      		List<VoteItems> voteitems = dao.findAll();
      		request.setAttribute("voteitems", voteitems);
      		request.getRequestDispatcher("vote_result.jsp").
      			forward(request, response);
      	}
      }
  
 

      <%@ page language="java" contentType="text/html; charset=utf-8"%>
      <%@ page import="java.util.*,com.javaweb.entity.*,com.javaweb.dao.*,com.javaweb.dao.impl.*" %>
      <%
      	VoteItemsDao voteDao = new VoteItemsDaoImpl();
      	List<VoteItems> votes = voteDao.findAll();
      %>
      <html>
      <head>
      <title>调查问卷</title>
      <style>
     	.outside{					/* 外层表格 */
     		background:url(bg1.jpg);
     		font-size:12px;
     		padding:0px;
      	}
     	.title{						/* 表格标题 */
     		color:#FFFFFF;
     		font-weight:bold;
     		text-align:center;
     		padding-top:3px;
     		padding-bottom:0px;
      	}
     	.tdoutside{
     		padding:0px 1px 4px 1px;
      	}
     	.inside{					/* 内层表格 */
     		width:269px;
     		font-size:12px;
     		padding:0px;
     		margin:0px;
      	}
     	.tdinside{
     		padding:7px 0px 7px 10px;
     		background-color:#FFD455;
      	}
     	form{
     		margin:0px; padding:0px;
      	}
     	input{
     		font-size:12px;
      	}
     	a{
     		color:#000000;
      	}
      </style></head>
      <body>
      <table class="outside">
     	<tr><td class="title">点调查</td></tr>
     	<tr><td class="tdoutside">
     		<form method="post" action="UpdateVoteServlet">
     		<table class="inside" cellspacing="0">
     			<tr>
     				<td class="tdinside">
      				你对哪种技术最感兴趣<br>
      				<%
      					for(VoteItems v:votes){
      						%>
     						<input type="checkbox" name="items" value="<%=v.getId() %>"><%=v.getItem() %><br>
      						<%
      					}
      				 %>
     				<input type="submit" value="提交">
     				<a href="ShowResultServlet">查看结果</a>
     				</td>
     			</tr>
     		</table>
     		</form>
     	</td></tr>
      </table>
      </body>
      </html>
  
 

      <%@ page language="java" import="java.util.*,com.javaweb.entity.*" pageEncoding="utf-8"%>
      <%
      String path = request.getContextPath();
      String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
      	List<VoteItems> voteitems =
      		(List<VoteItems>)request.getAttribute("voteitems");
      %>
      <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
      <html>
       <head>
         <base href="<%=basePath%>">
         <title>My JSP 'vote_result.jsp' starting page</title>
     	<meta http-equiv="pragma" content="no-cache">
     	<meta http-equiv="cache-control" content="no-cache">
     	<meta http-equiv="expires" content="0">
     	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
     	<meta http-equiv="description" content="This is my page">
     	<!--
       <link rel="stylesheet" type="text/css" href="styles.css">
       -->
       </head>
       <body>
         <table>
          	<%
          		for(VoteItems v:voteitems){
          	 %>
         	<tr>
         		<td><%=v.getItem() %></td>
         		<td><%=v.getTimes() %></td>
         	</tr>
          	<%} %>
         </table>
       </body>
      </html>
  
 

文章来源: aaaedu.blog.csdn.net，作者：tea_year，版权归原作者所有，如需转载，请联系作者。

原文链接：aaaedu.blog.csdn.net/article/details/53138122