Servlet投票系统，简单增删改查.zip

package dao; import java.sql.*; import java.util.ArrayList; import java.util.List; import bean.Topic; public class TopicDao { public List<Topic> query(){ Connection c=null; List<Topic> list =new ArrayList<Topic>(); try{ c=ConnectionManager.getConnection(); String sql="select * from topic"; PreparedStatement pst=c.prepareStatement(sql); ResultSet rs=pst.executeQuery(); while(rs.next()){ Topic topic =new Topic(); topic.setId(rs.getInt("id")); topic.setTitle(rs.getString("title")); topic.setOption1(rs.getString("option1")); topic.setOption2(rs.getString("option2")); topic.setOption3(rs.getString("option3")); topic.setOption4(rs.getString("option4")); topic.setStartTime(rs.getDate("startTime")); topic.setEndTime(rs.getDate("endTime")); topic.setCount1(rs.getInt("count1")); topic.setCount2(rs.getInt("count2")); topic.setCount3(rs.getInt("count3")); topic.setCount4(rs.getInt("count4")); list.add(topic); } return list; }catch(Exception e){ e.printStackTrace(); return null; }finally{ ConnectionManager.closeConnection(c); } } public boolean insert(Topic topic){ Connection c=null ; ; try{ c=ConnectionManager.getConnection(); String sql="insert into topic(title,startTime,endTime,isStart,option1,option2,option3,option4,count1,count2,count3,count4) values (?,?,?,0,?,?,?,?,0,0,0,0)"; PreparedStatement pst=c.prepareStatement(sql); pst.setString(1,topic.getTitle()); pst.setString (2,String.valueOf(topic.getStartTime())); pst.setString(3,String.valueOf(topic.getStartTime())); pst.setString(4,topic.getOption1()); pst.setString(5,topic.getOption2()); pst.setString(6,topic.getOption3()); pst.setString(7,topic.getOption4()); //pst.setString(8,topic.getOption5()); pst.execute(); return true; }catch(Exception e){ e.printStackTrace(); return false; }finally{ ConnectionManager.closeConnection(c); } } public Topic query(int id){ Connection c=null ; ; try{ c=ConnectionManager.getConnection(); String sql="select * from topic where id=?"; PreparedStatement pst=c.prepareStatement(sql); pst.setInt(1,id); ResultSet rs=pst.executeQuery(); if(rs.next()){ Topic topic=new Topic(); topic.setId(rs.getInt("id")); topic.setTitle(rs.getString("title")); topic.setStartTime(rs.getDate("startTime")); topic.setEndTime(rs.getDate("endTime")); topic.setIsStart(rs.getInt("isStart")); topic.setOption1(rs.getString("option1")); topic.setOption2(rs.getString("option2")); topic.setOption3(rs.getString("option3")); topic.setOption4(rs.getString("option4")); topic.setCount1(rs.getInt("count1")); topic.setCount2(rs.getInt("count2")); topic.setCount3(rs.getInt("count3")); topic.setCount4(rs.getInt("count4")); return topic; }else{ return null; } }catch(Exception e){ e.printStackTrace(); return null; }finally{ ConnectionManager.closeConnection(c); } } public boolean vote(int id,int option){ Connection c=null; try{ c=ConnectionManager.getConnection(); String sql=""; if(option==1){ sql="update topic set count1=count1+1 where id=?"; }else if(option==2){ sql="update topic set count2=count2+1 where id=?"; }else if(option==3){ sql="update topic set count3=count3+1 where id=?"; }else if(option==4){ sql="update topic set count4=count4+1 where id=?"; } PreparedStatement pst=c.prepareStatement(sql); pst.setInt(1, id); pst.execute(); return true; }catch(Exception e){ e.printStackTrace(); return false; }finally{ ConnectionManager.closeConnection(c); } } public boolean delete(int id){ Connection c=null; try{ c=ConnectionManager.getConnection(); String sql="delete from topic where id=?"; PreparedStatement pst=c.prepareStatement(sql); pst.setInt(1,id); pst.execute(); return true; }catch(Exception e){ e.printStackTrace(); return false; }finally{ ConnectionManager.closeConnection(c); } } public boolean update(Topic topic,int id){ Connection c=null; try{ c=ConnectionManager.getConnection(); String sql="update topic set title=?,startTime=?,endTime=?,option1=?,option2=?,option3=?,option4=? where id=?"; PreparedStatement pst=c.prepareStatement(sql); pst.setString(1, topic.getTitle()); pst.setDate(2, topic.getStartTime()); pst.setDate(3, topic.getEndTime()); pst.setString(4, topic.getOption1()); pst.setString(5, topic.getOption2()); pst.setString(6, topic.getOption3()); pst.setString(7, topic.getOption4()); //System.out.println(topic.getCount1()+" "+topic.getOption1()+" "+topic.getTitle()+" id is: "+id); pst.setInt(8,id); pst.execute(); return true; }catch(Exception e){ e.printStackTrace(); return false; }finally{ ConnectionManager.closeConnection(c); } } public static void main(String args[]){ TopicDao topicdao=new TopicDao(); //List<Topic> list=topicdao.query(); //System.out.println(""+list.size()); //TopicDao topicdao=new TopicDao(); Topic topic =new Topic(); topic.setTitle(""); topic.setStartTime(new Date(2017-1-6)); topic.setEndTime(new Date(2017-2-6)); topic.setOption1("1"); topic.setOption2("2"); topic.setOption3("sadfadfsux2"); topic.setOption4("lad"); //boolean b=topicdao.update(topic,11); boolean b=topicdao.insert(topic); //System.out.println("update "+b);*/ //Topic topic=topicdao.query(1); //boolean c=topicdao.vote(1, 3); //boolean c=topicdao.update(topic, 17); //boolean c=topicdao.delete(10); System.out.print(b); } }