git-test/JDBCUtils.java

package 学生成绩查询管理系统.JDBC;

import javax.swing.*;
import java.sql.*;

public class JDBCUtils {

    private static Connection conn;
    private static Statement stmt;
    private static final String drivername = "com.mysql.cj.jdbc.Driver";
    private static final String Url = "jdbc:mysql://localhost:3306/studentmanager";
    private static final String username = "root";
    private static final String password = "123456";

    static {
        try {
            Class.forName(drivername);
        } catch (ClassNotFoundException e) {
            JOptionPane.showMessageDialog(null, "加载数据库驱动出错，请查明原因！");
        }
        try {
            conn = DriverManager.getConnection(Url, username, password);
            stmt = conn.createStatement();
        } catch (SQLException e) {
            JOptionPane.showMessageDialog(null, "数据库驱动出错，用户名或密码错误！");
        }
    }

    public boolean admincheckLogin(String useraccount, String userpassword) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;

        try {
            // 创建数据库连接
            connection = DriverManager.getConnection(Url, username, password);

            // 编写SQL查询语句
            String sql = "SELECT * FROM userdatabases WHERE account = ? AND password = ?";

            // 创建预编译的语句对象
            statement = connection.prepareStatement(sql);

            // 设置参数
            statement.setString(1, useraccount);
            statement.setString(2, userpassword);

            // 执行查询并获取结果集
            resultSet = statement.executeQuery();

            // 返回是否存在匹配的记录
            return resultSet.next();

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            // 关闭数据库资源
            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (statement != null) {
                    statement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        return false; // 出现异常或查询失败时返回false
    }

    public boolean teachercheckLogin(String useraccount, String userpassword) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;

        try {
            // 创建数据库连接
            connection = DriverManager.getConnection(Url, username, password);

            // 编写SQL查询语句
            String sql = "SELECT * FROM teacheraccount WHERE account = ? AND password = ?";

            // 创建预编译的语句对象
            statement = connection.prepareStatement(sql);

            // 设置参数
            statement.setString(1, useraccount);
            statement.setString(2, userpassword);

            // 执行查询并获取结果集
            resultSet = statement.executeQuery();

            // 返回是否存在匹配的记录
            return resultSet.next();

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            // 关闭数据库资源
            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (statement != null) {
                    statement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        return false; // 出现异常或查询失败时返回false
    }

    public boolean studentcheckLogin(String useraccount, String userpassword) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;

        try {
            // 创建数据库连接
            connection = DriverManager.getConnection(Url, username, password);

            // 编写SQL查询语句
            String sql = "SELECT * FROM studentaccount WHERE account = ? AND password = ?";

            // 创建预编译的语句对象
            statement = connection.prepareStatement(sql);

            // 设置参数
            statement.setString(1, useraccount);
            statement.setString(2, userpassword);

            // 执行查询并获取结果集
            resultSet = statement.executeQuery();

            // 返回是否存在匹配的记录
            return resultSet.next();

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            // 关闭数据库资源
            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (statement != null) {
                    statement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        return false; // 出现异常或查询失败时返回false
    }
}