基于java+servlet+mysql学生信息管理系统-期末大作业

package service; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; import dao.StuDao; import model.Student; import utils.DBUtils; public class StuService implements StuDao {//实现接口 Connection con=null;//定义全局变量 @Override//实现方法 public List<Student> selectAll() {//查询所有 List<Student> list=new ArrayList<Student>();//定义list集合 try { con=DBUtils.getConnection();//获取连接 String sql="select * from student";// PreparedStatement pst=con.prepareStatement(sql);//执行sql ResultSet rs=pst.executeQuery();//获取查询结果集 while(rs.next()){//ֹ Student stu=new Student();//实例化对象 stu.setId(rs.getInt("id")); stu.setsNo(rs.getString("sNo"));//传参 stu.setsName(rs.getString("sName")); stu.setsAge(rs.getInt("sAge")); stu.setsAddress(rs.getString("sAddress")); stu.setSchool(rs.getString("school")); list.add(stu);//丢到list集合里 } } catch (Exception e) { e.printStackTrace(); } finally{ DBUtils.closeConnection(con);//关闭连接 } return list;//返回list集合 } @Override public int delete(Integer id) { try { con=DBUtils.getConnection(); String sql="delete from student where id=?"; PreparedStatement pst=con.prepareStatement(sql); pst.setInt(1,id); pst.executeUpdate(); } catch (Exception e) { e.printStackTrace(); return 0; } finally{ DBUtils.closeConnection(con); } return 1; } @Override public boolean insert(Student stu) { String sql="insert into student(sNo,sName,sAge,sAddress,school) values(?,?,?,?,?)"; try { con=DBUtils.getConnection(); PreparedStatement pst=con.prepareStatement(sql); pst=con.prepareStatement(sql); pst.setString(1, stu.getsNo()); pst.setString(2, stu.getsName()); pst.setInt(3,stu.getsAge()); pst.setString(4, stu.getsAddress()); pst.setString(5, stu.getSchool()); pst.execute(); return true; } catch (Exception e) { e.printStackTrace(); return false; } finally{ DBUtils.closeConnection(con); } } @Override public boolean update(Student stu,Integer id) { //TODO Auto-generated method stub try{ con=DBUtils.getConnection(); String sql="update student set sNo=?, sName=?,sAge=?,sAddress=?,school=? where id=?"; PreparedStatement pst=con.prepareStatement(sql); pst.setString(1,stu.getsNo()); pst.setString(2,stu.getsName()); pst.setInt(3,stu.getsAge()); pst.setString(4,stu.getsAddress()); pst.setString(5, stu.getSchool()); pst.setLong(6,id); pst.execute(); return true; }catch(Exception e){ e.printStackTrace(); return false; }finally{ DBUtils.closeConnection(con); } } @Override public List<Student> findBysName(String sName) { Connection con=null; List<Student> list =new ArrayList<Student>(); try{ con=DBUtils.getConnection(); String sql="select * from student where sName like ?"; PreparedStatement pst=con.prepareStatement(sql); pst.setString(1, "%"+sName+"%"); ResultSet rs=pst.executeQuery(); while(rs.next()) { Student stu =new Student(); stu.setId(rs.getInt("id")); stu.setsNo(rs.getString("sNo"));//传参 stu.setsName(rs.getString("sName")); stu.setsAge(rs.getInt("sAge")); stu.setsAddress(rs.getString("sAddress")); stu.setSchool(rs.getString("school")); list.add(stu); } return list; }catch(Exception e){ e.printStackTrace(); return null; }finally{ DBUtils.closeConnection(con); } } @Override public Student findBysNo(Integer id) { try{ con=DBUtils.getConnection(); String sql="select * from student where id=?"; PreparedStatement pst=con.prepareStatement(sql); pst.setInt(1,id); ResultSet rs=pst.executeQuery(); if(rs.next()){ Student stu=new Student(); stu.setId(rs.getInt("id")); stu.setsNo(rs.getString("sNo")); stu.setsName(rs.getString("sName")); stu.setsAge(rs.getInt("sAge")); stu.setSchool(rs.getString("school")); stu.setsAddress(rs.getString("sAddress")); return stu; }else{ return null; } }catch(Exception e){ e.printStackTrace(); return null; }finally{ DBUtils.closeConnection(con); } } public static void main(String[] args) { StuService s=new StuService(); //System.out.println(b); List<Student> list=s.findBysName("李"); for(Student st:list) { System.out.println(st.getsAddress()); } } }