sms_0.4.rar_beginning3t1_java

package com.djg.sms.dao.impl; 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.djg.sms.dao.IStudentDao; import com.djg.sms.domain.Student; import com.djg.sms.util.JDBCUtil; public class StudentDaoJDBCImpl implements IStudentDao { @Override public List<Student> findAll() { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; List<Student> stuList = null; try { conn = JDBCUtil.getConnection(); String sql = "select * from t_student"; ps = conn.prepareStatement(sql); rs = ps.executeQuery(); //遍历结果集 if(rs != null){ boolean flag = true; while(rs.next()){ if(flag){ stuList = new ArrayList<Student>(); flag = false; } Student s = new Student(); s.setSno(rs.getInt("sno")); s.setName(rs.getString("name")); s.setMyclass(rs.getString("myclass")); s.setScore(rs.getDouble("score")); stuList.add(s); } } } catch (SQLException e) { e.printStackTrace(); } return stuList; } @Override public Student findById(int id) { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; Student student = null; try { conn = JDBCUtil.getConnection(); String sql = "select * from t_student where sno = ?"; ps = conn.prepareStatement(sql); ps.setInt(1, id); rs = ps.executeQuery(); //遍历结果集 if(rs != null){ while(rs.next()){ student = new Student(); student.setSno(rs.getInt("sno")); student.setName(rs.getString("name")); student.setMyclass(rs.getString("myclass")); student.setScore(rs.getDouble("score")); } } } catch (SQLException e) { e.printStackTrace(); } return student; } @Override public int add(Student s) { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; int n = 0; try { conn = JDBCUtil.getConnection(); String sql = "insert into t_student (name,myclass,score) values(?,?,?)"; ps = conn.prepareStatement(sql); ps.setString(1, s.getName()); ps.setString(2, s.getMyclass()); ps.setDouble(3, s.getScore()); n = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return n; } @Override public int deleteById(int id) { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; int n = 0; try { conn = JDBCUtil.getConnection(); String sql = "delete from t_student where sno = ?"; ps = conn.prepareStatement(sql); ps.setInt(1, id); n = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return n; } @Override public int modify(int id, Student s) { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; int n = 0; try { conn = JDBCUtil.getConnection(); String sql = "update t_student set name=?,myclass=?,score=? where sno=?"; ps = conn.prepareStatement(sql); ps.setString(1, s.getName()); ps.setString(2, s.getMyclass()); ps.setDouble(3, s.getScore()); ps.setInt(4, id); n = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return n; } @Override public int findTotalCount() { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; int n = 0; try { conn = JDBCUtil.getConnection(); String sql = "select count(*) as totalcount from t_student"; ps = conn.prepareStatement(sql); rs = ps.executeQuery(); if(rs != null){ while(rs.next()){ n = rs.getInt("totalcount"); } } } catch (SQLException e) { e.printStackTrace(); } return n; } @Override public List<Student> findOnePage(int pageIndex, int pageSize) { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; List<Student> stuList = null; //计算分页相关参数 //变量startRecordNo 存储的是当前分页第一条记录的前一个位置 int startRecordNo = (pageIndex - 1) * pageSize; try { conn = JDBCUtil.getConnection(); String sql = "select * from t_student limit ?,?"; ps = conn.prepareStatement(sql); ps.setInt(1, startRecordNo); ps.setInt(2, pageSize); rs = ps.executeQuery(); //遍历结果集 if(rs != null){ boolean flag = true; while(rs.next()){ if(flag){ stuList = new ArrayList<Student>(); flag = false; } Student s = new Student(); s.setSno(rs.getInt("sno")); s.setName(rs.getString("name")); s.setMyclass(rs.getString("myclass")); s.setScore(rs.getDouble("score")); stuList.add(s); } } } catch (SQLException e) { e.printStackTrace(); } return stuList; } }