public boolean select(String email) {

    con = (Connection) DBConnector.getConnection();

    try {
      String sql = "SELECT mail_address FROM user WHERE mail_address = ?";
      ps = (PreparedStatement) con.prepareStatement(sql);
      ps.setString(1, email);
      ResultSet rs = ps.executeQuery();
      if (rs.next()) {
        rs.getString(1);
        result = true;
      }
    } catch (SQLException e) {
      e.printStackTrace();
    } finally {
      if (con != null) {
        try {
          con.close();
        } catch (SQLException e) {
          e.printStackTrace();
        }
      }
    }
    return result;
  }
  /**
   * ユーザー情報をDBから取得する為のメソッド
   *
   * @return boolean 処理の成否
   */
  public boolean selectToUser(int userId, ModifyInformationDTO dto) {

    boolean result = false;

    con = (Connection) DBConnector.getConnection();

    String sql = "SELECT * FROM user WHERE user_id = ? ";

    try {
      PreparedStatement ps = (PreparedStatement) con.prepareStatement(sql);
      ps.setInt(1, userId);
      ResultSet resultSet = ps.executeQuery();

      if (resultSet.next()) {
        dto.setUserName(resultSet.getString("user_name"));
        dto.setNameKana(resultSet.getString("name_kana"));
        dto.setPostNumber(resultSet.getString("post_number"));
        dto.setAddress1(resultSet.getString("street_address1"));
        dto.setAddress2(resultSet.getString("street_address2"));
        dto.setAddress3(resultSet.getString("street_address3"));
        dto.setPhoneNumber(resultSet.getString("phone_number"));
        dto.setEmail(resultSet.getString("mail_address"));
        dto.setPassword(resultSet.getString("password"));
        dto.setCreditNumber(resultSet.getString("credit_number"));
        dto.setToken(resultSet.getString("token"));
        dto.setUserId(resultSet.getInt("user_id"));

        result = true;
      }

    } catch (SQLException e) {
      e.printStackTrace();
    } finally {
      try {
        con.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
    return result;
  }