Java Web项目开发案例精粹02投票系统源码

package com.sanqing.daoImpl; 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.sanqing.bean.Vote; import com.sanqing.dao.VoteDAO; import com.sanqing.util.DBConnection; import com.sanqing.util.Page; public class VoteDAOImpl implements VoteDAO{ public void addVote(Vote vote) { Connection conn = DBConnection.getConnection(); //获得连接对象 String addSQL = "insert into " + "tb_vote(voteName,channelID) values(?,?)"; PreparedStatement pstmt = null; //声明预处理对象 try { pstmt = conn.prepareStatement(addSQL); //获得预处理对象并赋值 pstmt.setString(1, vote.getVoteName()); //设置投票名称 pstmt.setInt(2, vote.getChannelID()); //设置频道ID pstmt.executeUpdate(); //执行添加 } catch (SQLException e) { e.printStackTrace(); } finally{ DBConnection.close(pstmt); //关闭预处理对象 DBConnection.close(conn); //关闭连接对象 } } public void deleteVote(int voteID) { Connection conn = DBConnection.getConnection(); //获得连接对象 String deleteSQL = "delete from tb_vote where voteID=?"; PreparedStatement pstmt = null; //声明预处理对象 try { pstmt = conn.prepareStatement(deleteSQL); //获得预处理对象并赋值 pstmt.setInt(1, voteID); //设置投票编号 pstmt.executeUpdate(); //执行删除 } catch (SQLException e) { e.printStackTrace(); } finally{ DBConnection.close(pstmt); //关闭预处理对象 DBConnection.close(conn); //关闭连接对象 } } public List<Vote> findAllVote(Page page) { Connection conn = DBConnection.getConnection(); //获得连接对象 String findByIDSQL = "select * from tb_vote limit ?,?"; //查询SQL语句 PreparedStatement pstmt = null; //声明预处理对象 ResultSet rs = null; List<Vote> votes = new ArrayList<Vote>(); try { pstmt = conn.prepareStatement(findByIDSQL); //获得预处理对象并赋值 pstmt.setInt(1, page.getBeginIndex()); pstmt.setInt(2, page.getEveryPage()); rs = pstmt.executeQuery(); //执行查询 while(rs.next()) { Vote vote = new Vote(); vote.setVoteID(rs.getInt(1)); vote.setVoteName(rs.getString(2)); vote.setChannelID(rs.getInt(3)); votes.add(vote); } } catch (SQLException e) { e.printStackTrace(); } finally{ DBConnection.close(rs); //关闭结果集对象 DBConnection.close(pstmt); //关闭预处理对象 DBConnection.close(conn); //关闭连接对象 } return votes; } public Vote findVoteById(int voteID) { Connection conn = DBConnection.getConnection(); //获得连接对象 String querySQL = "select * from tb_vote where voteID = ?"; PreparedStatement pstmt = null; //声明预处理对象 ResultSet rs = null; Vote vote = null; try { pstmt = conn.prepareStatement(querySQL); //获得预处理对象并赋值 pstmt.setInt(1, voteID); rs = pstmt.executeQuery(); //执行查询 if(rs.next()) { vote = new Vote(); vote.setVoteID(rs.getInt(1)); vote.setVoteName(rs.getString(2)); vote.setChannelID(rs.getInt(3)); } } catch (SQLException e) { e.printStackTrace(); } finally{ DBConnection.close(rs); //关闭结果集对象 DBConnection.close(pstmt); //关闭预处理对象 DBConnection.close(conn); //关闭连接对象 } return vote; } public void updateVote(Vote vote) { } public Vote findVoteByName(String voteName) { Connection conn = DBConnection.getConnection(); //获得连接对象 String querySQL = "select * from tb_vote where voteName = ?"; PreparedStatement pstmt = null; //声明预处理对象 ResultSet rs = null; Vote vote = null; try { pstmt = conn.prepareStatement(querySQL); //获得预处理对象并赋值 pstmt.setString(1, voteName); rs = pstmt.executeQuery(); //执行查询 if(rs.next()) { vote = new Vote(); vote.setVoteID(rs.getInt(1)); vote.setVoteName(rs.getString(2)); vote.setChannelID(rs.getInt(3)); } } catch (SQLException e) { e.printStackTrace(); } finally{ DBConnection.close(rs); //关闭结果集对象 DBConnection.close(pstmt); //关闭预处理对象 DBConnection.close(conn); //关闭连接对象 } return vote; } public int findAllCount() { Connection conn = DBConnection.getConnection(); //获得连接对象 String findSQL = "select count(*) from tb_vote"; PreparedStatement pstmt = null; //声明预处理对象 ResultSet rs = null; int count = 0; try { pstmt = conn.prepareStatement(findSQL); //获得预处理对象并赋值 rs = pstmt.executeQuery(); //执行查询 if(rs.next()) { count = rs.getInt(1); } } catch (SQLException e) { e.printStackTrace(); } finally{ DBConnection.close(rs); //关闭结果集对象 DBConnection.close(pstmt); //关闭预处理对象 DBConnection.close(conn); //关闭连接对象 } return count; } public List<Vote> findVoteByChannel(Page page, int channelID) { Connection conn = DBConnection.getConnection(); //获得连接对象 String findByIDSQL = "select * from tb_vote where channelID=? limit ?,?"; //查询SQL语句 PreparedStatement pstmt = null; //声明预处理对象 ResultSet rs = null; List<Vote> votes = new ArrayList<Vote>(); try { pstmt = conn.prepareStatement(findByIDSQL); //获得预处理对象并赋值 pstmt.setInt(1, channelID); pstmt.setInt(2, page.getBeginIndex()); pstmt.setInt(3, page.getEveryPage()); rs = pstmt.executeQuery(); //执行查询 while(rs.next()) { Vote vote = new Vote(); vote.setVoteID(rs.getInt(1)); vote.setVoteName(rs.getString(2)); vote.setChannelID(rs.getInt(3)); votes.add(vote); } } catch (SQLException e) { e.printStackTrace(); } finally{ DBConnection.close(rs); //关闭结果集对象 DBConnection.close(pstmt); //关闭预处理对象 DBConnection.close(conn); //关闭连接对象 } return votes; } public int fintCountByChannel(int channelID) { Connection conn = DBConnection.getConnection(); //获得连接对象 String findSQL = "select count(*) from tb_vote where channelID=?"; PreparedStatement pstmt = null; //声明预处理对象 ResultSet rs = null; int count = 0; try { pstmt = conn.prepareStatement(findSQL); //获得预处理对象并赋值 pstmt.setInt(1, channelID); rs = pstmt.executeQuery(); //执行查询 if(rs.next()) { count = rs.getInt(1); } } catch (SQLException e) { e.printStackTrace(); } finally{ DBConnection.close(rs); //关闭结果集对象 DBConnection.close(pstmt); //关闭预处理对象 DBConnection.close(conn); //关闭连接对象 } return count; } }