问使用servlet时No suitable driver found for jabc:mysql？

public class jdbctest {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        int i=0;
        try {
//            Class.forName("com.mysql.cj.jdbc.Driver");注释，因为可以自动加载
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/student?" +
                    "user=root&password=richtev&serverTimezone=UTC");

            //不需要Classforname自动加载合适驱动
            stmt = conn.createStatement();
            String sql = "insert into user (name,age)values('kkk',18)";
            i = stmt.executeUpdate(sql);
            if(i>0){
                System.out.println("插入成功");
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            UtilJDBC.close(conn,stmt,rs);

        }
    }

}

public class studentService {
    //student数据访问类
    public int addStudent(Student stu){
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet re = null;
        System.out.println(stu.getName());
        System.out.println(stu.getAge());
        int i=-1;
        //注册，连接，
        try {
            //这行代码就会出错，完全复制过来的
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/student?" +
                    "user=root&password=richtev&serverTimezone=UTC");
            //这行代码就会出错，完全复制过来的
            
            String sql = "insert into user (name,age) values(?,?)";
           ps = conn.prepareStatement(sql);
           ps.setString(1,stu.getName());
           ps.setInt(2,stu.getAge());
           i = ps.executeUpdate();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            UtilJDBC.close(conn,ps,re);
        }
        return i;

    }
}