网上在线考试系统 （带完整数据库）

package com.wgh.dao; import com.wgh.actionForm.StudentForm; import com.wgh.core.ChStr; import com.wgh.core.ConnDB; import java.sql.*; import java.text.SimpleDateFormat; import java.util.*; import java.text.NumberFormat; public class StudentDAO { private ConnDB conn=new ConnDB(); private ChStr chStr=new ChStr(); //考生身份验证 public int checkStudent(StudentForm studentForm) { int flag = 1; String sql = "SELECT * FROM tb_student where ID='" + studentForm.getID()+ "'"; ResultSet rs = conn.executeQuery(sql); try { if (rs.next()) { String pwd = studentForm.getPwd(); if (pwd.equals(rs.getString(3))) { rs.last(); int rowSum = rs.getRow(); //获取记录总数 rs.first(); if (rowSum!=1) { flag = 2; System.out.print("获取row的值：" + sql + rowSum); } } else { flag = 2; } }else{ flag = 2; } } catch (Exception ex) { flag = 2; System.out.println(ex.getMessage()); } return flag; } //添加数据 public String insert(StudentForm s) { String sql1="SELECT * FROM tb_student WHERE cardNo='"+s.getCardNo()+"'"; ResultSet rs = conn.executeQuery(sql1); //执行SQL查询语句 String sql = ""; String falg = "miss"; //用于记录返回信息的变量 String ID=""; try { if (rs.next()) { //假如存在记录 falg="re"; //表示考生信息已经注册 } else { /*****************自动生成准考证号***********************************************/ String sql_max="SELECT max(ID) FROM tb_student"; ResultSet rs_max=conn.executeQuery(sql_max); //查询最大的准考证号 java.util.Date date=new java.util.Date(); //实例化java.util.Date()类 String newTime=new SimpleDateFormat("yyyyMMdd").format(date); //格式化当前日期 if(rs_max.next()){ String max_ID=rs_max.getString(1); //获取最大的准考证号 int newId=Integer.parseInt(max_ID.substring(10,16))+1;//取出最大准考证号中的数字编号+1 String no=chStr.formatNO(newId,6); //将生成的编号格式化为6位 ID="CN"+newTime+no; //组合完整的准考证号 }else{ //当第一个考生注册时 ID="CN"+newTime+"000001"; //生成第一个准考证号 } /********************************************************************************/ sql = "INSERT INTO tb_student (ID,name,pwd,sex,question,answer,profession,cardNo) values('" + ID+ "','" +s.getName() +"','"+s.getPwd()+"','"+s.getSex()+"','"+s.getQuestion()+ "','"+s.getAnswer()+"','"+s.getProfession()+"','"+s.getCardNo()+"')"; int ret= conn.executeUpdate(sql); //保存考生注册信息 if(ret==0){ falg="miss"; //表示考生注册失败 }else{ falg="恭喜您，注册成功!\\r请记住您的准考证号："+ID; //返回生成的准考证号 } conn.close(); //关闭数据库连接 } } catch (Exception e) { falg="miss"; System.out.println("添加考生信息时的错误信息："+e.getMessage()); //输出错误提示信息到控制台 } return falg; } //查询方法 public List query(String id) { List studentList = new ArrayList(); StudentForm studentForm1 = null; String sql=""; if(id==null ||id.equals("")){ sql = "SELECT * FROM tb_student ORDER BY joinTime DESC"; }else{ sql = "SELECT * FROM tb_student WHERE id='" +id+ "'"; } ResultSet rs = conn.executeQuery(sql); try { while (rs.next()) { studentForm1 = new StudentForm(); studentForm1.setID(rs.getString(1)); studentForm1.setName(rs.getString(2)); studentForm1.setPwd(rs.getString(3)); studentForm1.setSex(rs.getString(4)); studentForm1.setJoinTime(java.text.DateFormat.getDateTimeInstance().parse(rs.getString(5))); studentForm1.setQuestion(rs.getString(6)); studentForm1.setAnswer(rs.getString(7)); studentForm1.setProfession(rs.getString(8)); studentForm1.setCardNo(rs.getString(9)); studentList.add(studentForm1); } } catch (Exception ex) {} return studentList; } //修改考生资料 public int update(StudentForm s){ String sql="UPDATE tb_student SET pwd='"+s.getPwd()+"',sex='"+s.getSex()+"',question='"+s.getQuestion()+"',answer='"+s.getAnswer()+"',profession='"+s.getProfession()+"' where ID='"+s.getID()+"'"; int ret=conn.executeUpdate(sql); System.out.println("修改考生资料时的SQL："+sql); conn.close(); return ret; } //找回密码（第一步） public StudentForm seekPwd1(StudentForm s){ String sql="SELECT * FROM tb_student WHERE ID='"+s.getID()+"'"; ResultSet rs = conn.executeQuery(sql); try { if (rs.next()) { s.setID(rs.getString(1)); s.setQuestion(rs.getString(6)); }else{ s.setID(""); } }catch(Exception e){ System.out.println("找回密码（第一步）出现的错误信息："+e.getMessage()); } return s; } // 找回密码（第二步） public StudentForm seekPwd2(StudentForm s){ String sql="SELECT * FROM tb_student WHERE ID='"+s.getID()+"'"; System.out.println("SQL"+sql); ResultSet rs = conn.executeQuery(sql); try { if (rs.next()) { String ID=rs.getString(1); String pwd=rs.getString(3); String answer=rs.getString(7); if(answer.equals(s.getAnswer())){ s.setID(ID); s.setPwd(pwd); System.out.println("密码："+pwd); }else{ s.setID(""); } } }catch(Exception e){ System.out.println("找回密码（第二步）出现的错误信息："+e.getMessage()); } return s; } // 删除数据 public int delete(StudentForm studentForm) { int flag=0; String[] delId=studentForm.getDelIdArray(); if (delId.length>0){ String id="'"; for(int i=0;i<delId.length;i++){ id=id+delId[i]+"','"; } id=id.substring(0,id.length()-2); String sql = "DELETE FROM tb_student where id in (" + id +")"; System.out.println("删除时的SQL："+sql); flag = conn.executeUpdate(sql); conn.close(); }else{ flag=0; } return flag; } }