jsp连接mysql空指针

<%@ page import="java.sql.*" %>
<%
    try {
        // 加载MySQL JDBC驱动程序
        Class.forName("com.mysql.cj.jdbc.Driver");

        // 数据库连接URL
        String url = "jdbc:mysql://localhost:3306/mydatabase?useSSL=false&serverTimezone=UTC";

        // 数据库用户名和密码
        String user = "myuser";
        String password = "mypassword";

        // 建立数据库连接
        Connection conn = DriverManager.getConnection(url, user, password);

        // 执行查询
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery("SELECT * FROM mytable");

        // 处理查询结果
        while (rs.next()) {
            out.println(rs.getString("columnName"));
        }

        // 关闭资源
        rs.close();
        stmt.close();
        conn.close();
    } catch (ClassNotFoundException e) {
        out.println("MySQL JDBC驱动程序未找到");
    } catch (SQLException e) {
        out.println("数据库连接错误: " + e.getMessage());
    }
%>