@FXML
private void savaconfig(ActionEvent event) {
    try {
        Properties prop = new Properties();
        FileWriter fw = new FileWriter("conf" + File.separator + "config.properties");
        BufferedWriter br = new BufferedWriter(fw);

        String sqlmapPath = this.id_textFeild.getText(); 

        prop.setProperty("SqlmapPath", sqlmapPath);

        prop.store(br, "配置文件");

        br.close();
        new Alert(Alert.AlertType.NONE, "已保存到配置文件config.properties", new ButtonType[] { ButtonType.CLOSE }).show();
    }
    catch (Exception e) {
        new Alert(Alert.AlertType.NONE, "未找到配置文件config.properties", new ButtonType[] { ButtonType.CLOSE }).show();
        e.printStackTrace();
    }
}

保存到properties