ssg-web workspace 日程管理系统

package com.wwx.schedule.dao; /** * ClassName: BaseDao * Package: com.wwx.schedule.dao * Description: * * @Author 吴伟贤 * @Create 2024/4/19 14:53 * @Version 1.0 */ import com.wwx.schedule.util.JDBCUtil; import java.lang.reflect.Field; import java.sql.*; import java.time.LocalDateTime; import java.util.ArrayList; import java.util.List; public class BaseDao { // 公共的查询方法 返回的是单个对象 public <T> T baseQueryObject(Class<T> clazz, String sql, Object ... args) { T t = null; Connection connection = JDBCUtil.getConnection(); PreparedStatement preparedStatement = null; ResultSet resultSet = null; int rows = 0; try { // 准备语句对象 preparedStatement = connection.prepareStatement(sql); // 设置语句上的参数 for (int i = 0; i < args.length; i++) { preparedStatement.setObject(i + 1, args[i]); } // 执行 查询 resultSet = preparedStatement.executeQuery(); if (resultSet.next()) { t = (T) resultSet.getObject(1); } } catch (Exception e) { e.printStackTrace(); } finally { if (null != resultSet) { try { resultSet.close(); } catch (SQLException e) { e.printStackTrace(); } } if (null != preparedStatement) { try { preparedStatement.close(); } catch (SQLException e) { e.printStackTrace(); } } JDBCUtil.releaseConnection(); } return t; } // 公共的查询方法 返回的是对象的集合 public <T> List<T> baseQuery(Class clazz, String sql, Object ... args){ List<T> list =new ArrayList<>(); Connection connection = JDBCUtil.getConnection(); PreparedStatement preparedStatement=null; ResultSet resultSet =null; int rows = 0; try { // 准备语句对象 preparedStatement = connection.prepareStatement(sql); // 设置语句上的参数 for (int i = 0; i < args.length; i++) { preparedStatement.setObject(i+1,args[i]); } // 执行 查询 resultSet = preparedStatement.executeQuery(); ResultSetMetaData metaData = resultSet.getMetaData(); int columnCount = metaData.getColumnCount(); // 将结果集通过反射封装成实体类对象 while (resultSet.next()) { // 使用反射实例化对象 Object obj =clazz.getDeclaredConstructor().newInstance(); for (int i = 1; i <= columnCount; i++) { String columnName = metaData.getColumnLabel(i); Object value = resultSet.getObject(columnName); // 处理datetime类型字段和java.util.Data转换问题 if(value.getClass().equals(LocalDateTime.class)){ value= Timestamp.valueOf((LocalDateTime) value); } Field field = clazz.getDeclaredField(columnName); field.setAccessible(true); field.set(obj,value); } list.add((T)obj); } } catch (Exception e) { e.printStackTrace(); } finally { if (null !=resultSet) { try { resultSet.close(); } catch (SQLException e) { throw new RuntimeException(e); } } if (null != preparedStatement) { try { preparedStatement.close(); } catch (SQLException e) { throw new RuntimeException(e); } } JDBCUtil.releaseConnection(); } return list; } // 通用的增删改方法 public int baseUpdate(String sql,Object ... args) { // 获取连接 Connection connection = JDBCUtil.getConnection(); PreparedStatement preparedStatement=null; int rows = 0; try { // 准备语句对象 preparedStatement = connection.prepareStatement(sql); // 设置语句上的参数 for (int i = 0; i < args.length; i++) { preparedStatement.setObject(i+1,args[i]); } // 执行 增删改 executeUpdate rows = preparedStatement.executeUpdate(); // 释放资源(可选) } catch (SQLException e) { e.printStackTrace(); } finally { if (null != preparedStatement) { try { preparedStatement.close(); } catch (SQLException e) { throw new RuntimeException(e); } } JDBCUtil.releaseConnection(); } // 返回的是影响数据库记录数 return rows; } }