网络软件开发 基于web的高校教学考试成绩管理系统 Java html jsp tomcat service项目 MySQL数据

package com.utils; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class DataBaseBean { String url = "jdbc:mysql://localhost:3306/practiceone"+"?&serverTimezone=GMT%2B8"; String user = "root"; String pwd = "20190225";/* vary with different users */ Connection connection; Statement statement; ResultSet resultSet; static { try { Class.forName("com.mysql.cj.jdbc.Driver"); } catch (ClassNotFoundException e) { e.printStackTrace(); } } public DataBaseBean() { try { connection = DriverManager.getConnection(url, user, pwd); } catch (SQLException e) { e.printStackTrace(); } } public void execute(String sql) throws Exception { statement = connection.createStatement(); statement.execute(sql); } public void executeUpdate(String sql) { try { statement = connection.createStatement(); statement.executeUpdate(sql); } catch (SQLException e) { e.printStackTrace(); } } public ResultSet executeQuery(String sql) { try { statement = connection.createStatement(); resultSet = statement.executeQuery(sql); } catch (SQLException e) { e.printStackTrace(); } return resultSet; } public void close() { if (resultSet != null) { try { resultSet.close(); } catch (SQLException e) { e.printStackTrace(); } } if (statement != null) { try { statement.close(); } catch (SQLException e) { e.printStackTrace(); } } if (connection != null) { try { connection.close(); } catch (SQLException e) { e.printStackTrace(); } } } }