Java+JSP+Mysql实现Web学校教材管理系统

package com.sjsq.dao.impl; import com.sjsq.dao.MaterialDao; import com.sjsq.entity.Material; import com.sjsq.utils.DBUtil; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; /** * @author: shuijianshiqing * @date: 2022-03-03 * @description: */ public class MaterialDaoImpl implements MaterialDao { @Override public List<Material> selectAll(String sql, Object[] arr) { Connection con = null; PreparedStatement ps = null; ResultSet rs = null; try { // 1.连接数据库 con = DBUtil.getConnection(); // 2.预编译 ps = con.prepareStatement(sql); if (arr != null) { for (int i = 0; i < arr.length; i++) { // 传入sql的参数,向上转型,某个栏位的查询 ps.setObject(i + 1, arr[i]); } } // 3.执行sql rs = ps.executeQuery(); // 4.保存查询出来的数据到list List<Material> list = new ArrayList<>(); while (rs.next()) { Material material = new Material(); material.setId(rs.getInt("id")); material.setName(rs.getString("name")); material.setAuthor(rs.getString("author")); material.setPublish(rs.getString("publish")); material.setNumberr(rs.getString("number")); list.add(material); } return list; } catch (Exception e) { e.printStackTrace(); } finally { // 关闭链接，避免数据库连接过多 DBUtil.close(con, ps, rs); } return null; } @Override public Material selectMaterial(Integer id) { Connection con = null; PreparedStatement ps = null; ResultSet rs = null; try { // 1.连接数据库 con = DBUtil.getConnection(); // 2.预编译 String sql = "select * from material where id = ?"; ps = con.prepareStatement(sql); ps.setInt(1, id); // 3.执行sql rs = ps.executeQuery(); while (rs.next()) { Material material = new Material(); material.setId(rs.getInt("id")); material.setName(rs.getString("name")); material.setAuthor(rs.getString("author")); material.setPublish(rs.getString("publish")); material.setNumberr(rs.getString("number")); return material; } } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { // 关闭资源，避免出现异常 DBUtil.close(con, ps, rs); } return null; } @Override public boolean addMaterial(Material material) { String sql = "insert into material values (?,?,?,?,?)"; List<Object> list = new ArrayList<Object>(); list.add(material.getId()); list.add(material.getName()); list.add(material.getAuthor()); list.add(material.getPublish()); list.add(material.getNumber()); boolean flag = DBUtil.addUpdateDelete(sql, list.toArray()); if (flag) { return true; } else { return false; } } @Override public boolean updateMaterial(Material material) { String sql = "update material set name=?,author=?,publish=?,number=? where id=?"; List<Object> list = new ArrayList<Object>(); list.add(material.getName()); list.add(material.getAuthor()); list.add(material.getPublish()); list.add(material.getNumber()); // 注意id在最后面 list.add(material.getId()); boolean flag = DBUtil.addUpdateDelete(sql, list.toArray()); if (flag) { return true; } else { return false; } } @Override public boolean deleteMaterial(Integer id) { String sql = "delete from material where id=?"; List<Object> list = new ArrayList<Object>(); list.add(id); boolean flag = DBUtil.addUpdateDelete(sql, list.toArray()); if (flag) { return true; } else { return false; } } }