mvc简易学生管理系统

package com.hs.dao.impl; import com.hs.dao.StudentDao; import com.hs.entity.Student; import com.hs.until.DbUtil01; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; public class StudentDaoImpl implements StudentDao { private DbUtil01 db=new DbUtil01(); @Override public List<Student> findAllStudent() { String sql="select * from student"; Object[] objs={}; List<Student> studentList=new ArrayList<>(); try { ResultSet resultSet = db.select(sql, objs); while (resultSet.next()){ Student student=new Student(); student.setSid(resultSet.getInt("sid")); student.setSname(resultSet.getString("sname")); student.setSsex(resultSet.getString("ssex")); student.setSage(resultSet.getInt("sage")); studentList.add(student); } } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); }finally { db.close(); } return studentList; } @Override public int addStudent(String sname, String ssex, String sage) { String sql="insert into student values(null,?,?,?)"; Object[] o={sname,ssex,sage}; int i= 0; try { i = db.update(sql,o); } catch (SQLException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } finally { db.close(); } return i; } @Override public int deleteStudent(int sid) { Object[] objs={sid}; String sql="delete from student where sid=?"; int i=0; try { i = db.update(sql, objs); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); }finally { db.close(); } return i; } @Override public Student findStudentBySid(int sid) { String sql="select * from student where sid=?"; Object[] objs={sid}; Student student=null; try { ResultSet select = db.select(sql, objs); if (select.next()){ student=new Student(); student.setSid(select.getInt("sid")); student.setSname(select.getString("sname")); student.setSsex(select.getString("ssex")); student.setSage(select.getInt("sage")); } } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); }finally { db.close(); } return student; } @Override public int updateStudentBySid(int sid, String sname, String ssex, String sage) { String sql="update student set sname=?,ssex=?,sage=? where sid=?"; Object[] objc={sname,ssex,sage,sid}; int i=0; try { i = db.update(sql, objc); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); }finally { db.close(); } return i; } }