package com.WR.StudentMS.dao.mysql; 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.WR.StudentMS.dao.Coursemdaoqsy; import com.WR.StudentMS.model.Coursemqsy; public class Coursemdaoimplqsy implements Coursemdaoqsy { @Override public List findAllqsy() { String sql = "select id,name,jieshao from t_kecheng"; List coursemqsy = new ArrayList(); try ( Connection conn = DBHelper.getConnection(); PreparedStatement pstmt = conn.prepareStatement(sql); ResultSet rs = pstmt.executeQuery()) { while (rs.next()) { Coursemqsy coursem = new Coursemqsy(); coursem.setCourseidqsy(rs.getString("id")); coursem.setCoursenameqsy(rs.getString("name")); coursem.setJieshaoqsy(rs.getString("jieshao")); coursemqsy.add(coursem); } } catch (SQLException e) { e.printStackTrace(); } return coursemqsy; } @Override public Coursemqsy findByIdqsy(String courseid) { String sql = "SELECT id, name, jieshao FROM t_kecheng WHERE id = ?"; try ( Connection conn = DBHelper.getConnection(); PreparedStatement pstmt = conn.prepareStatement(sql); ) { pstmt.setString(1, courseid); ResultSet rs = pstmt.executeQuery(); if (rs.next()) { Coursemqsy coursem = new Coursemqsy(); coursem.setCourseidqsy(rs.getString("id")); coursem.setCoursenameqsy(rs.getString("name")); coursem.setJieshaoqsy(rs.getString("jieshao")); return coursem; } } catch (SQLException e) { e.printStackTrace(); } return null; } @Override public int createqsy(Coursemqsy coursem) { String sql = "insert into t_kecheng (id, name, jieshao) values (?,?,?)"; try ( Connection conn = DBHelper.getConnection(); PreparedStatement pstmt = conn.prepareStatement(sql) ) { pstmt.setString(1, coursem.getCourseidqsy()); pstmt.setString(2, coursem.getCoursenameqsy()); pstmt.setString(3, coursem.getJieshaoqsy()); // 确保这里的占位符数量与SQL语句中的一致 int affectedRows = pstmt.executeUpdate(); System.out.printf("成功插入%d条数据\n", affectedRows); return affectedRows; // 如果插入成功,返回受影响的行数 } catch (SQLException e) { // 打印异常信息,以便于调试 e.printStackTrace(); // 如果发生异常,返回-1表示操作失败 return -1; } } @Override public int removeqsy(Coursemqsy coursem) { String sql = "delete from t_kecheng where id = ?"; // 只使用 id 作为删除条件 try ( Connection conn = DBHelper.getConnection(); PreparedStatement pstmt = conn.prepareStatement(sql) ) { pstmt.setString(1, coursem.getCourseidqsy()); // 设置要删除的课程的 id int affectedRows = pstmt.executeUpdate(); System.out.printf("成功删除%d条数据\n", affectedRows); // 修正控制台输出信息 return affectedRows; // 返回受影响的行数 } catch (SQLException e) { e.printStackTrace(); // 打印异常信息 return -1; // 发生异常时返回-1 } } }