public void performTask(HttpServletRequest request, HttpServletResponse response) throws IOException, ClassNotFoundException, SQLException {
        response.setContentType("text/html; charset=Cp1251");
        PrintWriter out = response.getWriter();
        Class.forName("org.postgresql.Driver");
        Connection connection = DriverManager.getConnection("jdbc:postgresql://127.0.0.1:5432/my_postgres_db", "postgres_user", "ytn88vfys");

        Statement st = connection.createStatement();
        ResultSet rs = st.executeQuery("SELECT * FROM pacient");
        int columns = rs.getMetaData().getColumnCount();

        while (rs.next()) {
            for (int i = 1; i <= columns; i++) {
                out.print(rs.getString(i) + "\n");
            }
        }

    }