SSH三大框架经典例子

package com.livechain.dao; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import com.livechain.model.Student; public class StudentDAO { private Connection conn; private PreparedStatement ps; private ResultSet rs; public StudentDAO() { conn = DBConnection.openConnection(); } //关闭资源 public void closeResource() { try { if(rs!=null) { rs.close(); rs = null; } if(ps!=null) { ps.close(); ps = null; } if(conn!=null) { conn.close(); conn = null; } } catch (Exception e) { e.printStackTrace(); } } //添加学生方法 public int addStudent(Student student) { int result = 0; String sql = "INSERT INTO students(sname,sexy,age,school) VALUES(?,?,?,?)"; try { ps = conn.prepareStatement(sql); ps.setString(1,student.getSname()); ps.setString(2,student.getSexy()); ps.setInt(3,student.getAge()); ps.setString(4,student.getSchool()); result = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } finally { this.closeResource(); } return result; } //修改学生信息方法 public int updateStudent(Student student) { int result = 0; String sql = "UPDATE students SET sname=?,sexy=?,age=?,school=? WHERE sid=?"; try { ps = conn.prepareStatement(sql); int i = 1; ps.setString(i++,student.getSname()); ps.setString(i++,student.getSexy()); ps.setInt(i++,student.getAge()); ps.setString(i++,student.getSchool()); ps.setInt(i++,student.getSid()); result = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return result; } //查询所有学生信息 public List<Student> getAllStudents() { List<Student> list = new ArrayList<Student>(); String sql = "SELECT * FROM students"; try { ps = conn.prepareStatement(sql); rs = ps.executeQuery(); Student student = null; while(rs.next()) { student = new Student(); student.setSid(rs.getInt("sid")); student.setSname(rs.getString("sname")); student.setSexy(rs.getString("sexy")); student.setAge(rs.getInt("age")); student.setSchool(rs.getString("school")); list.add(student); } } catch (SQLException e) { e.printStackTrace(); } return list; } //通过编号查学生信息 public Student getStudentById(Integer id) { Student student = null; String sql = "SELECT * FROM students WHERE sid=?"; try { ps = conn.prepareStatement(sql); ps.setInt(1,id); rs = ps.executeQuery(); if(rs.next()) { student = new Student(); student.setSid(rs.getInt("sid")); student.setSname(rs.getString("sname")); student.setSexy(rs.getString("sexy")); student.setAge(rs.getInt("age")); student.setSchool(rs.getString("school")); } } catch (SQLException e) { e.printStackTrace(); } return student; } //通过ID删除学生 public int deleteStudentById(Integer id) { int result = 0; String sql = "DELETE FROM students WHERE sid=?"; try { ps = conn.prepareStatement(sql); int i = 1; ps.setInt(i++,id); result = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return result; } }