javaweb项目：校园宿舍管理系统

package com.dao; import com.db.DBHelper; import com.bean.StudentBean; import java.util.*; import java.sql.*; public class StudentDao { //验证登录 public String CheckLogin(String username, String password){ String id = null; String sql="select * from Student where Student_Username='"+username+"' and Student_Password='"+password+"' and Student_State='入住'"; Statement stat = null; ResultSet rs = null; Connection conn = new DBHelper().getConn(); try{ stat = conn.createStatement(); rs = stat.executeQuery(sql); while (rs.next()) { id = rs.getString("Student_ID"); } } catch(SQLException ex){} return id; } //验证密码 public boolean CheckPassword(String id, String password){ boolean ps = false; String sql="select * from Student where Student_ID='"+id+"' and Student_Password='"+password+"'"; Statement stat = null; ResultSet rs = null; Connection conn = new DBHelper().getConn(); try{ stat = conn.createStatement(); rs = stat.executeQuery(sql); while (rs.next()) { ps=true; } } catch(SQLException ex){} return ps; } //获取所有列表 public List<StudentBean> GetAllList(String strwhere,String strorder){ String sql="select * from Student"; if(!(isInvalid(strwhere))) { sql+=" where "+strwhere; } if(!(isInvalid(strorder))) { sql+=" order by "+strorder; } // System.out.println(sql); Statement stat = null; ResultSet rs = null; Connection conn = new DBHelper().getConn(); List<StudentBean> list=new ArrayList<StudentBean>(); try{ stat = conn.createStatement(); rs = stat.executeQuery(sql); while(rs.next()){ StudentBean cnbean=new StudentBean(); cnbean.setStudent_ID(rs.getInt("Student_ID")); cnbean.setStudent_DomitoryID(rs.getInt("Student_DomitoryID")); cnbean.setStudent_Username(rs.getString("Student_Username")); cnbean.setStudent_Password(rs.getString("Student_Password")); cnbean.setStudent_Name(rs.getString("Student_Name")); cnbean.setStudent_Sex(rs.getString("Student_Sex")); cnbean.setStudent_Class(rs.getString("Student_Class")); cnbean.setStudent_State(rs.getString("Student_State")); list.add(cnbean); } } catch (SQLException e) { e.printStackTrace(); } finally { try { if (conn != null) conn.close(); if (stat != null) stat.close(); if (rs != null) rs.close(); } catch (SQLException e) { e.printStackTrace(); } } return list; } //获取列表 public List<StudentBean> GetList(String strwhere,String strorder){ String sql="select * from Student,Domitory,Building where Student_DomitoryID=Domitory_ID and Domitory_BuildingID=Building_ID"; if(!(isInvalid(strwhere))) { sql+=" and "+strwhere; } if(!(isInvalid(strorder))) { sql+=" order by "+strorder; } // System.out.println(sql); Statement stat = null; ResultSet rs = null; Connection conn = new DBHelper().getConn(); List<StudentBean> list=new ArrayList<StudentBean>(); try{ stat = conn.createStatement(); rs = stat.executeQuery(sql); while(rs.next()){ StudentBean cnbean=new StudentBean(); cnbean.setStudent_ID(rs.getInt("Student_ID")); cnbean.setStudent_DomitoryID(rs.getInt("Student_DomitoryID")); cnbean.setStudent_Username(rs.getString("Student_Username")); cnbean.setStudent_Password(rs.getString("Student_Password")); cnbean.setStudent_Name(rs.getString("Student_Name")); cnbean.setStudent_Sex(rs.getString("Student_Sex")); cnbean.setStudent_Class(rs.getString("Student_Class")); cnbean.setStudent_State(rs.getString("Student_State")); cnbean.setDomitory_Name(rs.getString("Domitory_Name")); cnbean.setBuilding_Name(rs.getString("Building_Name")); cnbean.setDomitory_Type(rs.getString("Domitory_Type")); cnbean.setDomitory_Number(rs.getString("Domitory_Number")); cnbean.setDomitory_Tel(rs.getString("Domitory_Tel")); list.add(cnbean); } } catch (SQLException e) { e.printStackTrace(); } finally { try { if (conn != null) conn.close(); if (stat != null) stat.close(); if (rs != null) rs.close(); } catch (SQLException e) { e.printStackTrace(); } } return list; } //获取指定ID的实体Bean public StudentBean GetAllFirstBean(String strwhere){ String sql="select * from Student where "+strwhere; Statement stat = null; ResultSet rs = null; Connection conn = new DBHelper().getConn(); StudentBean cnbean=new StudentBean(); try{ stat = conn.createStatement(); rs = stat.executeQuery(sql); if(rs.next()){ cnbean.setStudent_ID(rs.getInt("Student_ID")); cnbean.setStudent_DomitoryID(rs.getInt("Student_DomitoryID")); cnbean.setStudent_Username(rs.getString("Student_Username")); cnbean.setStudent_Password(rs.getString("Student_Password")); cnbean.setStudent_Name(rs.getString("Student_Name")); cnbean.setStudent_Sex(rs.getString("Student_Sex")); cnbean.setStudent_Class(rs.getString("Student_Class")); cnbean.setStudent_State(rs.getString("Student_State")); } } catch (SQLException e) { e.printStackTrace(); } finally { try { if (conn != null) conn.close(); if (stat != null) stat.close(); if (rs != null) rs.close(); } catch (SQLException e) { e.printStackTrace(); } } return cnbean; } //获取指定ID的实体Bean public StudentBean GetFirstBean(String strwhere){ String sql="select * from Student,Domitory,Building where Student_DomitoryID=Domitory_ID and Domitory_BuildingID=Building_ID and "+strwhere; Statement stat = null; ResultSet rs = null; Connection conn = new DBHelper().getConn(); StudentBean cnbean=new StudentBean(); try{ stat = conn.createStatement(); rs = stat.executeQuery(sql); if(rs.next()){ cnbean.setStudent_ID(rs.getInt("Student_ID")); cnbean.setStudent_DomitoryID(rs.getInt("Student_DomitoryID")); cnbean.setStudent_Username(rs.getString("Student_Username")); cnbean.setStudent_Password(rs.getString("Student_Password")); cnbean.setStudent_Name(rs.getString("Student_Name")); cnbean.setStudent_Sex(rs.getString("Student_Sex")); cnbean.setStudent_Class(rs.getString("Student_Class")); cnbean.setStudent_State(rs.getString("Student_State")); cnbean.setDomitory_Name(rs.getString("Domitory_Name")); cnbean.setBuilding_Name(rs.getString("Building_Name")); } } catch (SQLException e) { e.printStackTrace(); } finally { try { if (conn != null) conn.close(); if (stat != null) stat.close(); if (rs != null) rs.close(); } catch (SQLException e) { e.printStackTrace(); } } return cnbean; } //获取指定ID的实体Bean public StudentBean GetAllBean(int id){ String sql="select * from Student where Student_ID="+id; Statement stat = null; ResultSet rs = null; Connection conn = new DBHelper().getConn(); StudentBean cnbean=new StudentBean(); try{ stat = conn.createStatement(); rs = stat.executeQuery(sql); while(rs.next()){ cnbean.setStudent_ID(rs.getInt("Student_ID")); cnbean.setStudent_DomitoryID(rs.getInt("Student_DomitoryID")); cnbean.setStudent_Username(rs.getString("Student_Username")); cnbean.setStudent_Password(rs.getString("Student_Password")); cnbean.setStudent_Name(rs.getString("Student_Name")); cnbean.setStudent_Sex(rs.getString("Student_Sex")); cnbean.setStudent_Class(rs.getString("Student_Class")); cnbean.setStudent_State(rs.getString("Student_State")); } } catch (SQLException e) { e.printStackTrace(); } finally { try { if (conn != null) conn.close(); if (stat != null) stat.close(); if (rs != null) rs.close(); } catch (SQLException e) { e.printStackTrace();